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  • 251. Rudenko, Oleg
    et al.
    Korobov, A
    Izosimova, M
    Nonlinearity of Solids with Micro- and Nanodefects and Characteristic Features of Its Macroscopic Manifestations2010Inngår i: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 56, nr 2, s. 151-157Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The meaning of the experimentally measured nonlinear parameters of a medium is discussed. The difference in meaning between the local nonlinearity, which is measured in the vicinity of a single defect and depends on the size of the region of averaging, and the effective volume nonlinearity of the medium containing numerous defects is emphasized. The local nonlinearity arising at the tip of a crack is calculated; this nonlinearity decreases with an increase in the region of second harmonic generation. The volume nonlinearity is calculated for a solid containing spherical cavities. The volume nonlinearity is also calculated for a medium containing infinitely thin cracks in the form of circular disks, which assume the shape of ellipsoids in the course of the crack opening. The nonlinear acoustic parameter is calculated with the use of the exact classical results of the theory of cracks.

  • 252. Rudenko, Oleg
    et al.
    Sarvazyan, Armen
    Wave Biomechanics of the Skeletal Muscle2006Inngår i: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 52, nr 6, s. 720-732Artikkel i tidsskrift (Fagfellevurdert)
  • 253. Rudenko, Oleg
    et al.
    Schvartburg, A
    Nonlinear and Linear Wave Phenomena in Narrow Pipes2010Inngår i: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 56, nr 4, s. 429-434Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Phenomena arising in the course of wave propagation in narrow pipes are considered. For nonlinear waves described by the generalized Webster equation, a simplified nonlinear equation is obtained that allows for low frequency geometric dispersion causing an asymmetric distortion of the periodic wave profile, which qualitatively resembles the distortion of a nonlinear wave in a diffracted beam. Tunneling of a wave through a pipe constriction is investigated. Possible applications of the phenomenon are discussed, and its relation to the problems of quantum mechanics because of the similarity of the basic equations of the Klein– Gordon and Schrödinger types is pointed out. The importance of studying the tunneling of nonlinear waves and broadband signals is indicated.

  • 254. Rudenko, Oleg
    et al.
    Sobisevich, A.L.
    Sobisevich, L.E.
    Hedberg, Claes
    Enhancements of energy and Q-factor of a nonlinear resonator with increase in its losses2002Inngår i: Doklady Akademii Nauk, ISSN 0869-5652, Vol. 383, nr 1, s. 330-333Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A phenomenon that is paradoxical at first sight is studied: an appropriately-organized energy outflow from a resonator cavity results not in the attenuation of nonlinear vibrations but in their noticeable enhancement. An increase in the resonator Q-factor and in the energy accumulated in it is well pronounced when the frequencies of the higher harmonics generated in a nonlinear medium are close to the natural frequencies of the resonator. An important example of a nonlinear system with the necessary properties is an acoustic resonator with selective losses.

  • 255. Rudenko, Oleg
    et al.
    Sobisevich, L.E.
    Sobisevich, A.L.
    Hedberg, Claes
    Nonlinear response of a layer to pulse action in diagnostics of small inhomogenities2000Inngår i: Doclady, Section Mechanics (Reports of the Russian Academy of Sciences) / Doklady Akademii Nauk, ISSN 0869-5652 , Vol. 374 ; 1-3, s. 194-197Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Giant nonlinear respons are observed at acoustic irradiation of microscopic gas bubbles in liquids, cracks and fluid-filled pores in solids; and compressed contact of rough surfaces, and is used in diagnostics of materials of industrial and geological structures. Reconstruction of characteristics of a scattering inhomogeneity requires an analyses of complicated inverse problems. The problem of plane-wave incidence upon a layer is simple and serves a model for more complicated inhomogeneities; its response enables us to reconstruct the spectral composition and field structure of other nonlinear scatterers.

  • 256. Rudenko, Oleg
    et al.
    Stepanov, P. V. Lebedev
    Gusev, V. A.
    Korobov, A. I.
    Korshak, B. A.
    Odina, N. I.
    Izosimova, M.
    Molchanovb, S. P.
    Alfimov, M. V.
    Control of the Self-Assembly Processes in a Droplet of a Colloidal Solution by an Acoustic Field2010Inngår i: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 56, nr 6, s. 935-941Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The formation of structured films consisting of ensembles of micro- or nanoparticles and possessing preset functional characteristics is studied both experimentally and theoretically. The films are obtained by drying out droplets of colloidal solutions on a solid substrate under the acoustic effect produced by a standing SAW field.

  • 257.
    Sandberg, Magnus
    et al.
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Währborg, Fredrik
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Dynamic Analysis of Handle Attachment for Brush Saws1999Annet (Annet vitenskapelig)
    Abstract [en]

    The user of a brush saw is exposed to vibrations in hands and arms. Theoretical and experimental modal analysis is used to investigate the handle attachment. The theoretical models are simplified to decrease the time for solving them. The methods and models of this work will later be used in the design process to decrease vibrations.

  • 258. Sarvazyan, Armen
    et al.
    Rudenko, Oleg
    Nyborg, Wesley
    Biomedical applications of radiation force of ultrasound: Historical roots and physical basis2010Inngår i: Ultrasound in Medicine and Biology, ISSN 0301- 5629, Vol. 36, nr 9, s. 1379-1394Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Radiation force is a universal phenomenon in any wave motion, electromagnetic or acoustic. Although acoustic and electromagnetic waves are both characterized by time variation of basic quantities, they are also both capable of exerting a steady force called radiation force. In 1902, Lord Rayleigh published his classic work on the radiation force of sound, introducing the concept of acoustic radiation pressure, and some years later, further fundamental contributions to the radiation force phenomenon were made by L. Brillouin and P. Langevin. Many of the studies discussing radiation force published before 1990 were related to techniques for measuring acoustic power of therapeutic devices; also, radiation force was one of the factors considered in the search for noncavitational, nonthermal mechanisms of ultrasonic bioeffects. A major surge in various biomedical applications of acoustic radiation force started in the 1990s and continues today. Numerous new applications emerged including manipulation of cells in suspension, increasing the sensitivity of biosensors and immunochemical tests, assessing viscoelastic properties of fluids and biological tissues, elasticity imaging, monitoring ablation of lesions during ablation therapy, targeted drug and gene delivery, molecular imaging and acoustical tweezers. We briefly present in this review the major milestones in the history of radiation force and its biomedical applications. In discussing the physical basis of radiation force and its applications, we present basic equations describing the relationship of radiation stress with parameters of acoustical fields and with the induced motion in the biological media. Momentum and force associated with a plane-traveling wave, equations for nonlinear and nonsteady-state acoustic streams, radiation stress tensor for solids and biological tissues and radiation force acting on particles and microbubbles are considered.

  • 259. Schenkman, Bo
    et al.
    Brunnström, Kjell
    Camera position and presentation scale for infrared night vision system in cars.2007Inngår i: Human Factors and Ergonomics in Manufacturing, ISSN 1090-8471 , Vol. 17, nr 5, s. 457-473Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Principles of an infrared night vision system in cars were studied in a stationary car simulator. The 20 participants drove for about 45 min on a rural route in night conditions where four objects were placed in or next to the road. When the camera was mounted on the grill of the car and the scale was true size, that is, 1:1, the time to collision was the longest. Changing the scale to a wide-angle view of 1:2 decreased this time. When the camera was mounted on the roof of the car, the scale change produced an increase of the time to collision. Principal omponents analysis indicated that the speed and the lateral position of the car were independent. The results were explained partly in terms of differences between the optic arrays presented to the drivers and to motion adaptation. It is suggested that the camera for a night vision system should be placed at the level of the car grill and the presentation scale should be 1:1.

  • 260. Scheuer, Johan
    et al.
    Håkansson, Lars
    Claesson, Ingvar
    Modal Analysis of a Boring Bar using Different Clamping Conditions2004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The internal turning operation is a common metal working process that is usually associated with vibration problems. Boring bars are often long and slender, making them prone to vibration when they are excited by the cutting forces introduced by the material deformation process in boring. The vibration causes degraded surface finish of the machined work piece, decreased tool life of inserts and boring bars, noise and other unwanted effects. Therefore, time-consuming planning and preparation have to be made in order to minimize vibration, affecting the cost of the machining process in the negative direction. It is possible to stabilize boring bars using active vibration control. To be able to do so, the dynamic properties of the bars have to be known in detail. Furthermore, with this knowledge, the results of using prediction tools for relating cutting parameters to cutting results may be significantly improved thanks to more relevant input data into the prediction tools. The effect of different clamping conditions on the dynamic properties of a boring bar's fundamental bending modes has been studied. Modal analysis was performed on a 40 mm-diameter boring bar with 100 mm clamping length and 200 mm overhang, making the L/D ratio 5. The clamping conditions have been varied by use of two different clamping devices. In each clamping device, several different clamping conditions were achieved by using different torque on the clamping screws. Results show that both the eigenfrequencies and the directions of the fundamental bending modes vary considerably due to the clamping conditions used.

  • 261. Sidenmark, Mikael
    et al.
    Josefsson, Andreas
    Berghuvud, Ansel
    Broman, Göran
    The Ocean Harvester: Modelling, Simulation & Experimental Validation2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Among the significant difficulties of developing commercially viable wave power has been survivability in storm conditions and achieving high capacity factors. The oscillating wave motion, constantly changing wave-size, and extreme energy levels during storm conditions often lead to difficulties in reaching high capacity factors, keeping the system complexity down and avoiding over dimensioning. The Ocean Harvester is based on an innovation addressing these issues. What is unique with this concept is the way a counterweight is used to achieve a limited load on the generator and thereby a levelled power output that can be controlled to match the average level of incoming wave energy. These characteristics enable an exceptionally high capacity factor, excellent survivability and low system complexity, which altogether may lead to low capital- and O&M costs. This paper presents the working principle of the novel concept and introductory coordinated theoretical and experimental investigations of performance characteristics. Theoretical and experimental results agree very well and further simulations with the verified model using real wave data clearly show the advantage of the proposed concept. A high capacity factor is proven and the design obviously only requires existing types of components, making cost-efficient wave energy conversion feasible.

  • 262. Smirnova, Tatiana
    Analysis, Modeling and Simulation of Machine Tool Parts Dynamics for Active Control of Tool Vibration2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Boring bar vibration in machine tools during internal turning operations is a pronounced problem in the manufacturing industry. Due to the often slender geometry of the boring bar, vibration may easily be induced by the material deformation process. One approach to overcome such vibration problems is to use active control of boring bar vibration. The design time of an active boring bar depends to a great extent on the knowledge of its dynamic properties when clamped in a lathe for different actuator positions and sizes, crucial for its performance. This thesis focuses on the development of accurate dynamic models of active boring bars with the purpose of providing qualitative information on suitable actuator position for a certain boring bar. The first part of the thesis considers the problem of building an accurate "3-D" finite element (FE) model of a standard boring bar used in industry. Results from experimental modal analysis of the actual boring bar are the reference. The second and the third parts discuss analytical and experimental methods for modeling the dynamic properties of a boring bar clamped in a machine tool. For this purpose, the Euler-Bernoulli and Timoshenko beam theories are used to produce both distributed-parameter system models and corresponding "1-D" FE models. A more complete "3-D" FE model of the system boring bar - clamping house is also developed. Spatial dynamic properties of these models are discussed and compared with adequate experimental modal analysis results from the actual boring bar clamped in a machine tool. The third part also investigates the sensitivity of the spatial dynamic properties of the derived boring bar models to variation in the structural parameters' values. The fourth part focuses on the development of a "3-D" FE model of the system boring bar - actuator - clamping house. Two models are discussed: a linear model and a model enabling variable contact between the clamping house and the boring bar with and without Coulomb friction in the contact surfaces. Based on these FE models fundamental bending modes and control path frequency response functions are discussed in conjunction with the corresponding quantities estimated for the actual active boring bar. In the fifth part, a method based on FE modeling and artificial neural networks for selecting a suitable actuator position inside an active boring bar is presented. Objective functions for selecting an actuator position are suggested. An active boring bar with an actuator position suggested by the method was manufactured and it displays fairly good correlation with the corresponding FE model. The final part focuses on modeling of an active boring bar vibration control system. A simple "1-D" FE model of a boring bar is utilized to simulate the dynamic response and an adaptive digital feedback controller realized by the feedback filtered-x LMS algorithm is used.

  • 263. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Claesson, Ingvar
    Håkansson, Lars
    Lagö, Thomas L
    Modeling a Clamped Boring Bar using Euler-Bernoulli Beam Models with Various Boundary Conditions2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper addresses modeling of a clamped boring bar using Euler-Bernoulli beam theory. Euler-Bernoulli beams with a number of different boundary conditions were used to model a clamped boring bar. Estimates of the boring bar's natural frequencies and mode shapes were produced with each of the boring bar models. The estimates produced by the distributed-parameter system models are compared with eigenfrequencies and mode shapes estimated based on experimental modal analysis of the actual boring bar clamped in a lathe.

  • 264. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Dynamic Modeling of a Boring Bar Using Theoretical and Experimental Engineering Methods Part 1: Distributed-Parameter System Modeling and Experimental Modal Analysis2009Inngår i: International Journal of Acoustics and Vibration, ISSN 1027-5851, Vol. 14, nr 3, s. 124-133Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Boring bar vibration is a common problem during internal turning operations and is a major problem for the manufacturing industry. High levels of boring bar vibration generally occur at frequencies related to the first two fundamental bending modes of a boring bar. This is the first of two companion papers that summarize the theoretical and experimental work carried out concerning modeling of dynamic properties of boring bars. This paper introduces the Timoshenko beam theory for the modeling of clamped boring bars. Also, the traditional Euler-Bernoulli beam theory is applied. These continuous system methods have been utilized to produce fixed-free beam models of the clamped boring bar. In order to improve accuracy of dynamic models of clamped boring bars, the modeling of the boring bar clamping is addressed by means of multi-span beam models with pinned boundary conditions. The derived boring bar models have also been compared with results obtained by means of experimental modal analysis, conducted on the actual boring bar clamped in a lathe. The multi-span beam boring bar models display higher correlation with experimental modal analysis results as compared to fixed-free beam models. For the fixed-free beams the Timoshenko model results in the highest correlation with the experimental results. On the other hand, the interval in frequency and the orientation of the two fundamental modes demonstrate differences, particularly between the continuous system models and the experimental results.

  • 265. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Dynamic Modeling of a Boring Bar Using Theoretical and Experimental Engineering Methods Part 2: Finite Element Modeling and Sensitivity Analysis2009Inngår i: International Journal of Acoustics and Vibration, ISSN 1027-5851, Vol. 14, nr 3, s. 134-142Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This is the second of two companion papers that summarize the theoretical and experimental work carried out concerning modeling of dynamic properties of boring bars. This paper introduces the finite element method for the modeling of clamped boring bars. The “3-D” FE models of the system boring bar – clamping house as well as the “1-D” FE models of the clamped boring bar were derived. In particular, the modeling of the boring bar clamping is addressed. Dynamic properties predicted based on the developed FE models of the clamped boring bar were compared with the ones estimated by means of experimental modal analysis conducted on the actual boring bar clamped in the lathe. The “3-D” FE models display substantially higher correlation with the experimental modal analysis results compared to the “1-D” FE models. A “3-D” FE model of the boring bar – clamping house manages to model the distance in frequency and the orientation of the two fundamental modes to a large extent. The importance of the modeling of the boring bar boundary conditions for the accuracy of dynamic models of boring bars is demonstrated. The sensitivity of the natural frequency estimates produced by means of the FE and the continuous system (presented in Part 1) boring bar models with respect to variations in material density and Young’s elastic modulus has been addressed.

  • 266. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Modeling of an Active Boring Bar2007Rapport (Annet vitenskapelig)
    Abstract [en]

    Vibration problems occurring during internal turning operations in the manufacturing industry urge for adequate passive and/or active control techniques in order to increase the productivity of machine tools. Usually, passive solutions are based on either boring bars made partly in high Young's modulus non-ductile materials such as intered tungsten carbide or boring bars with tuned vibration absorbers adjusted to increase the dynamic stiffness in the frequency range of a certain resonance frequency of the boring bar. By utilizing an active boring bar with an embedded piezoceramic actuator and a suitable controller, the primary boring bar vibrations originating from the material deformation process may be suppressed with actuator-induced secondary "anti-" vibrations. In order to design an active boring bar, several issues have to be addressed, i.e., selecting the characteristics of the actuator, the actuator size, the position of the actuator in the boring bar, etc. This usually implies the manufacturing and testing of several prototypes of an active boring bar, and this is a time-consuming and costly procedure. Therefore, mathematical models of active boring bars incorporating the piezo-electric effect that enable the accurate prediction of their dynamic properties and responses are of great importance. This report addresses the development of a "3-D" finite element model of the system "boring bar-actuator-clamping house". The spatial dynamic properties of the active boring bar, i.e., its natural frequencies and mode shapes, as well as the transfer function between actuator voltage and boring bar acceleration are calculated based on the "3-D" FE model and compared to the corresponding experimentally obtained estimates. Two types of approximations of the Coulomb friction force, the arctangent and the bilinear models, are evaluated concerning modeling contact between the surface of the boring bar and the clamping house.

  • 267. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Claesson, Ingvar
    Lagö, Thomas L
    Accurate FE-modeling of a Boring Bar Correlated with Experimental Modal Analysis2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In metal cutting the vibration problem of boring bars remains to be one of the most problematic and productivity degrading. A boring bar is very flexible and easily subjected to vibrations due to its large length to diameter ratio, which generally is required to perform internal turning. The boring bar vibrations appear at its first eigenfrequncies, which correspond to the boring bar’s first bending modes that are affected by boring bar’s boundary conditions applied by the clamping and workpiece in the lathe. Therefore the investigation of spatial dynamic properties of boring bars is of great importance for the understanding of the mechanism and nature of boring bars vibrations. This paper addresses the problem of building an accurate 3-D finite element model of a boring bar with ”free-free” boundary conditions. The questions of appropriate meshing and its influence on the boring bar’s spatial dynamic properties estimates as well as modeling the affect of mass loading are discussed. The results from simulations of 3-D finite element model of the boring bar, i.e. its first eigenmodes and eigenfrequencies, are correlated with the results obtained both from experimental modal analysis and analytical calculations using an Euler-Bernoulli model.

  • 268. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Claesson, Ingvar
    Lagö, Thomas L
    Estimation of an active boring bar´s control path FRF:s by means of its 3-D FE-model with Coulomb friction2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In metal cutting boring bar vibrations may be attenuated using an active boring bar with an embedded piezoceramic actuator, attached error sensor and a suitable controller. In the design of active boring bars accurate modelling of control path frequency response functions (FRF), i.e. FRF between the actuator voltage and the boring bars response signal (which is commonly acceleration), are of importance, e.g. for the decision concerning the favorable position of the actuator inside the active boring bar to maximize vibration suppression. This paper addresses the influence of the Coulomb friction force on the transfer function estimates between the actuator voltage and the boring bar acceleration calculated based on the ”3-D” FE model of an active boring bar. Two types of approximations of the Coulomb friction force, the arctangent and the bilinear models, are evaluated concerning modelling the contact between the surface of the boring bar and the clamping house. Results of incorporation of the two different Coulomb friction force models into the active boring bar’s SDOF model as well as ”3-D” FE-model enabling variable contact between the boring bar, the clamping screws and the clamping house are presented in terms of control path FRF:s.

  • 269. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Claesson, Ingvar
    Lagö, Thomas L
    Identification of Spatial Dynamic Properties of the Boring Bar by Means of Finite Element Model: Comparison with Experimental Modal Analysis and Euler-Bernoulli Model2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In metal cutting the boring operation is known to be one of the most troublesome regarding vibration. Boring bars are frequently subjected to vibrations originated from the load applied by the workpiece material deformation process. These vibrations are easily excited due to the boring bars general geometric dimensions, i.e. large length to diameter ratio. Large overhang is usually required to perform internal boring operation and is a consequence the vibration may frequently reach extremely high levels, which result in a poor surface finish, reduced tool life and annoying noise level in the working environment. The vibration problem is directly related to the first bending modes of a boring bar. Therefore investigations of the boring bar’s spatial dynamic properties are of a great importance. The results from experimental modal analysis show that a conventional analytical approach - calculation of boring bar eigenfrequencies using an Euler-Bernoulli model - results in rough estimates. This can be explained by existing nonlinearities introduced e.g. in the areas of contact between the boring bar and the clamping bolts as well as the clamping house, which is not considered in the analytical model where the boring bar instead is assumed to be rigidly clamped. Therefore the estimation of the eigenfrequencies and eigenmodes of a boring bar based on a 3-D finite element model of the clamped boring bar incorporating contact between the bar and the bolts respective the clamping house is a more beneficial strategy. This paper addresses the estimation of the boring bar’s first eigenfrequencies and corresponding eigenmodes based on the 3-D finite element model. The results are compared with results obtained both from experimental modal analysis and an analytical Euler-Bernoulli model.

  • 270. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Claesson, Ingvar
    Lagö, Thomas L
    INITIAL EXPERIMENTS WITH A FINITE ELEMENT MODEL OF AN ACTIVE BORING BAR2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    One of the most troublesome sources of vibration in metal cutting is the vibration caused by internal turning operations. A boring bar is a tool holder which is used to machine deep precise cavities inside a workpiece material. In order to perform this internal turning the boring bar usually has a large length-to-diameter ratio, and thus the boring bar vibrations are easily excited by the material deformation process during metal cutting. The vibrations are related to the lower order fundamental bending modes of the boring bar. To overcome the vibration problem an active control technique can be used. In particular, by utilizing an active boring bar with an embedded piezoceramic actuator and a suitable controller, the primary boring bar vibrations originating from the material deformation process may be suppressed with secondary "anti-" vibrations. In order to produce an active boring bar several decisions should be done, i.e. the characteristics of the actuator, the position of the actuator in the boring bar, etc. This usually implies that several prototypes of an active boring bar should be produced and tested, thus the design of an active boring bar is a tedious and costly procedure. Therefore a mathematical model which would incorporate the piezo-electric effect in order to predict the dynamic properties and the response of the active boring bar are of great importance. This paper addresses the development of a "3-D" finite element model of the system "boring bar-actuator-clamping house". The spatial dynamic properties of the active boring bar, i.e. its natural frequencies and mode shapes, as well as the transfer function between the voltage applied to the actuator and acceleration of boring bar are calculated based on the "3-D" FE model and compared to experimentally obtained estimates.

  • 271. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Claesson, Ingvar
    Lagö, Thomas L
    Investigation Concerning Actuator Position in an Active Boring Bar Regarding it´s Performance by Means of "3-D" Finite Element Models2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Active boring bars may be used for active vibration suppression during internal turning operation in metal cutting. This technique is based on a feedback control scheme of the boring bar vibrations measured by an attached sensor (usually accelerometer) where secondary "anti"- vibrations are applied by means of an embedded piezoelectric actuator. In order to design an active boring bar, several issues have to be addressed, i.e. selecting the characteristics of the actuator, the actuator size, the position of the actuator in the boring bar, etc. A mathematical model of the active boring bar incorporating the piezoelectric effect, e.g. a "3-D" finite element, may simplify designing process. In this paper several "3-D" finite element models of the system "boring bar - actuator - clamping house" are developed for a set of actuator positions. The favorable actuator position is basically selected as the one resulting in the greatest "stiffness" of the active boring bar at the frequency corresponding to the first boring bar fundamental bending mode.

  • 272. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Claesson, Ingvar
    Lagö, Thomas L
    Investigation Concerning Dynamic Properties of an Active Boring Bar Regarding its Perfomance by Means of ”1-D” Finite Element Models2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Active boring bars may be used for active vibration suppression during internal turning operations in metal cutting. This technique is typically based on a feedback control scheme of the boring bar vibrations measured by an attached sensor (usually accelerometer) where secondary ”anti”-vibrations are induced by means of an piezoelectric actuator embedded into a cavity located in the boring bar’s longitudinal direction below its central line. Design procedure of an active boring bar requires the selection of the characteristics of the actuator, the actuator size, the position of the actuator in the boring bar, etc. A ”3-D” finite element model of the active boring bar incorporating the piezoelectric effect was proposed previously to simplify the design process. The set of actuator positions used to decide the favorable actuator position was limited due to time-consuming transient response calculations of the ”3-D” finite element model of an active boring bar. In the present paper a larger set of ”1-D” finite element models of a boring bar (which model the position of the cavity for the actuator but do not incorporate piezoelectric effect) was used to predict dynamic properties of the active boring bar. Based on these results a small set of favorable actuator positions is selected for implementation in ”3-D” finite element models of active boring bars.

  • 273. Smirnova, Tatiana
    et al.
    Åkesson, Henrik
    Håkansson, Lars
    Claesson, Ingvar
    Lagö, Thomas L
    Investigation of Boring Bar Mode Shape Rotation by Experimental Modal Analysis in Correlation with Finite Element Modeling2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Productivity degrading vibration problems are traditional in metal cutting, in particular in internal turning, when the boring bar is long and slender. The high levels of vibrations arise at the boring bar’s natural frequencies corresponding to its fundamental bending modes. The vibrations are dominating at the boring bar’s eigenfrequency in the cutting speed direction, since the cutting force has the largest component in this direction. The negative effects of vibrations, e.g. poor surface finish, reduced tool life, high sound pressure levels in the working environment etc., can be eliminated for instance by using passive tuned damper or active control. The level of success implementing any of these methods is dependent on the knowledge of the dynamic properties of tooling structure - the interface between the cutting tool or insert and the machine tool - involved. Results from experimental modal analysis on the boring bar clamped in a lathe reveal a rotation of the mode shapes with respect to the cutting speed and cutting depth direction. The paper addresses boring bar mode shape rotation phenomenon and discusses its possible sources based on results obtained from experimental modal analysis of two systems: boring bar with original boundary conditions and boring bar with linearized boundary conditions in correlation with results obtained from corresponding 3-D finite element models.

  • 274.
    Song, Baiyi
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Evaluate Operational Modal Analysis and Compare the Result to Visualized Mode Shapes2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The prototypes vibration test carried out for obtaining reliable information concerning machine’s dynamic properties in development process. Analysis results should be able to correlate with FE model to determine if some underlying assumptions (material properties & boundary conditions) were correct. EMA used for extracting structure modal parameter under laboratory condition. However, EMA can generally not provide all required information concerning machine dynamic property. To simulate vibration in operating, it commonly requires the model based on dynamic properties of the machine under operating. Thus, vibration tests need carried out under operational condition. OMA is a useful tool for extracting information concerning dynamic properties of operating machine. This report concerns vibration test of part of mining machine under operating condition. Modal parameters extracted by two kinds of OMA methods. Results from OMA was compared with corresponding EMA results, illustrates reader the advantages of OMA.

  • 275. Sturesson, Per-Olof
    et al.
    Håkansson, Lars
    Claesson, Ingvar
    Identification of the Statistical Properties of the Cutting Tool Vibration in a Continuous Turning Operation: Correlation to Structural Properties1997Inngår i: Mechanical Systems & Signal Processing, ISSN 0888-3270 , Vol. 11, nr 3, s. 459-499Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cutting force dynamics in alloyed steel, stainless steel and cast iron have been investigated, although a direct measurement of the cutting forces could not be carried out. Usually, the response of the tool holder shank is measured by strain gauges and will be dependent on the stochastic character of the applied load and the structural dynamic properties of the tool holder. The characterisation of the dynamic response of the tool holder shank relies here on a stochastic approach while the structural dynamic properties were evaluated by a normal mode analysis. The results from both the analysis and the experiments correlate well.

  • 276. Stålhandske, Christina
    et al.
    Persson, Kent
    Lang, Maria
    Jönsson, Anders
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Fluid jet polishing of planar flat glass surfaces and within holes2014Inngår i: European Journal of Glass Science and Technology. Part A: Glass Technology, ISSN 1753-3546, Vol. 55, nr 2, s. 49-54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Planar ground float glass surfaces and the surfaces within holes are polished using fluid jet polishing (FJP) in order to improve their visual appearance or material strength. The large flexibility of FJP makes it suitable for polishing holes and other complex geometries. The influence of polishing speed, incident angle, distance, pressure, abrasive concentration, and nozzle diameter are investigated. Al2O3 is the abrasive used. The surface quality is evaluated visually and also measured with an optical profiler. The mechanical strength of the polished holes are evaluated with an MTS testing machine. Planar surfaces, and the surfaces of drilled and water cut holes are greatly improved by polishing. For a planar surface the lowest root mean square surface slope, Sdq, value achieved is 0·5 deg using 50% abrasive and 1000 mesh grains. The failure load of the glass with drilled holes increased 20% with FJP

  • 277.
    Thompson, Anthony
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för strategisk hållbar utveckling.
    Integrating a Strategic Sustainable Development Perspective in Product-Service System Innovation2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    There is an intersection of challenges where society’s social and ecological problems coincide with the industrial firm’s challenge to maintain profitability in a globalizing world. Products connect these challenges. The development of these products together with services (product-service systems) therefore provides a critical intervention point to address these challenges. This includes e.g. defining what the products and services are, how they will deliver value to users, and the business models that enable them to be realized, as well as how these can contribute to sustainable development of society. The overarching goal of this research is to contribute to sustainable development of society by better understanding how a strategic sustainable development perspective based on backcasting from basic principles for a sustainable society can be brought into and guide product-service system innovation. Interviews with industry professionals, workshops with both manufacturing companies and within student projects, and industrial cases studies, together with a review of literature and theoretical considerations, provide the methodological basis for this work. This thesis contributes to clarifying theoretical and practical possibilities and limitations for a strategic sustainable development perspective to guide product-service system innovation and provides a basis for the integration of these concepts. The findings indicate that the co-innovation of products and services in product-service systems can contribute to sustainable development of society both by supporting reduced material and energy use and by supporting improved life cycle management of materials. Further, a strategic sustainable development perspective can contribute to the refinement of existing tools and methods in product-service system innovation by providing an operational definition of sustainability articulated in the form of first-order principles that describe the boundary conditions for a sustainable society, and by providing guidelines for how to approach a vision of success inside those boundaries in a strategic way. In order to identify solutions that meet society’s pressing challenges, new solution spaces may need to be identified, and this can be enabled by a shift from product development with service as “add-ons” to their co-innovation in product-service systems. An initial approach for how this could be enabled through bringing together set-based approaches to design product-service systems with a strategic sustainable development perspective is presented.

  • 278.
    Thompson, Anthony
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för strategisk hållbar utveckling.
    Hallstedt, Sophie
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för strategisk hållbar utveckling.
    Isaksson, Ola
    Introductory approach for sustainability integration in conceptual design2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The introduction of sustainability-related requirements into new product development has been a popular topic since the 1990s, and one of the very roots of the topic – scarcity of resources – indicates that market forces will require improved ways of dealing with sustainability for product developing companies. The question remains, however, of the importance of considering sustainability aspects in product design, and if important - how to do it? This paper assumes importance and works to answer the question of how to do it by presenting an approach, currently under development, to include sustainabilty aspects in a generic design process by defining a sustainable design space inpsired by the early steps of a set-based concurrent engineering (SBCE) approach, and then describing how each stage of the generic design process can be aligned in order to arrive at more sustainable products.

  • 279. Thompson, Anthony
    et al.
    Larsson, Tobias
    Broman, Göran
    Towards Sustainability-driven Innovation through Product-Service Systems2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Many current sustainability considerations in industry constrain design space by emphasizing reduced material and energy flows across product life cycles. However, there are also opportunities for sustainability awareness to extend design space and drive innovation. Product-service systems (PSS) in particular can be a vehicle through which sustainability-driven innovation occurs. A framework for strategic sustainable development, including a backcasting approach, provides the basis for understanding sustainability in this work and provides insight into how incremental and radical approaches could be aligned within product innovation. This work explores how sustainability considerations can be better integrated into existing product innovation working environments, with an emphasis on opportunities that occur as sustainability knowledge leads to innovation through a product-service system approach. It is demonstrated and ideas are discussed around how sustainability can be used to drive innovation processes through product-service systems that companies rely upon, while also supporting global society’s movement toward sustainability.

  • 280. Thompson, Anthony
    et al.
    Lindahl, Pia
    Hallstedt, Sophie
    Ny, Henrik
    Broman, Göran
    Decision Support Tools for Sustainability in Product Innovation in a Few Swedish Companies2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Companies are finding that customers increasingly demand “sustainable products” while also noticing economic benefits from eco-efficiency and other sustainability-related design approaches. Employees making product-related decisions need support tools to incorporate sustainability considerations — both at strategic (e.g. regarding product lines to develop) and operational levels (e.g. detailed design). This paper presents the results from a set of interviews that explored where and how sustainability considerations are taken into account in the product innovation processes of six Swedish companies. Results are presented as a map of the overall company operations in relation to a generic product innovation model, followed by a map of the places where sustainability considerations are made in that model. Some of the tools that are used to support those sustainability considerations are also briefly described. The conclusion is that there are some, but not sufficient, tools and methods to support inclusion of sustainability aspects in the product innovation processes of these companies.

  • 281. Thompson, Anthony
    et al.
    Ny, Henrik
    Lindahl, Pia
    Broman, Göran
    Severinsson, Mikael
    Benefits of a Product Service System Approach for Long-life Products: The Case of Light Tubes2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Products designed for long-life often have significant potential for better sustainability performance than standard products due to less material and energy usage for a given service provided, which usually also results in a lower total cost. These benefits are not always obvious or appealing to customers, who often focus on price. Long-life products are therefore at an inherent disadvantage: due to lower volume of sales that results from the products’ longer-life, the margins (price) often need to be higher. In this paper, we demonstrate that when the revenue base is shifted to be the service of light (instead of the sales of light tubes), there is an opportunity for a “win-win-win” for the light user, the long-life light provider and society. Through a product-service system approach, resulting in a well-communicated total offer, the full array of benefits becomes clearer to the customer, including that they avoid the high initial cost.

  • 282. Tretten, Phillip
    et al.
    Gärling, Anita
    Nilsson, Rickard
    Larsson, Tobias
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    An on-road study of head-up display: Preferred location and acceptance levels2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The purpose of this study was to gain a better understanding of driver's perceptions of Head-Up Displays (HUD). Many HUD studies have been conducted but few have allowed drivers to test a HUD in their own vehicle, allowing them to choose the best HUD location for themselves. Forty participants drove their own vehicles using a portable HUD device, testing different HUD locations, and then rated the HUD using the Technology Acceptance Model. The results showed that the HUD was rated as easy to use and the drivers intended to use it in continuation. The drivers wanted the HUD to be located outside of the traffic scene, below their line of sight. These results give support for new HUD locations and for increased HUD implementation.

  • 283. Wall, Johan
    Dynamics Study of an Automobile Exhaust System2003Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Low vibration levels are a critical objective in automobile exhaust system design. It is therefore important for design engineers to be able to predict, describe and assess the dynamics of various system design proposals during product development. The aim of this thesis is to provide a deeper understanding of the dynamics of automobile exhaust systems to form a basis for improved design and the development of a computationally inexpensive theoretical system model. Modelling, simulation and experimental investigation of a typical exhaust system are performed to gain such an understanding and to evaluate modelling ideas. Special attention is given to the influence of the bellows-type flexible joint on the dynamics of the exhaust system. The investigations show that the exhaust system is essentially linear downstream of the flexible joint. Highly simplified finite element models of the major components within this part are suggested. These models incorporate adjustable flexibility in their connection to the exhaust pipes and a procedure is developed for automatic updating of these parameters to obtain better correlation with experimental results. The agreement between the simulation results of the updated models and the experimental results is very good, which confirms the usability of these models. Furthermore, the investigations show the great reduction of vibration transmission to the exhaust system that the bellows-type joint, either with or without an inside liner, gives in comparison with a stiff joint. For the combined bellows and liner joint, vibration transmission is, however, higher than for the bellows alone. Inclusion of the liner also makes the exhaust system behaviour significantly non-linear and complex, whereas the system behaviour proves to be essentially linear when the joint has no liner. This shows the importance of including a model of the liner in the theoretical system model when the liner is present in the real system. The choice of whether or not to include a liner in the real system is obviously a complex issue. The advantages of reduced bellows temperature and improved flow conditions should be weighed against the disadvantages found in this work. By combining the above findings it is concluded that in coming studies of how engine vibrations affect the exhaust system, the latter may be considered as a linear system if the flexible joint consists of a bellows. If the joint also includes a liner, the system may be considered as a linear subsystem that is excited via a non-linear joint.

  • 284. Wall, Johan
    Simulation-Driven Design of Complex Mechanical and Mechatronic Systems2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Effective and efficient product development is critical to business success on the increasingly competitive global market, and simulation has proven to support this in many sectors. The aim of this thesis is to study how properties of complex mechanical and mechatronic systems can be more efficiently and systematically predicted, described, assessed and improved in product development. The purpose is to elaborate an approach that can, rather than only verifying solutions that are already decided upon, support dialogues with customers, stimulate creation of new concepts and provide guidance towards more optimised designs, especially in early development stages. This is here termed simulation-driven design. To be useful for this, product models and simulation and optimisation procedures must be efficient, that is, they must accurately answer posed questions and point towards better solutions while consuming an acceptable amount of time and other resources. In this thesis a coordinated approach to create such efficient decision support is elaborated. This is done by action research through two industrial case studies; an automobile exhaust system representing a complex mechanical system and a water jet cutting machine representing a mechatronic system. The general knowledge gained from these case studies should be a good base for coming implementation of this approach as an inherent working routine in companies developing complex mechanical and mechatronic products. A specific result is a validated virtual model of the exhaust system, which facilitates fast structural dynamics simulation of customer proposed design layouts. It is also shown that the non-linear flexible joint between the manifold and the rest of the exhaust system makes the system behaviour complex. This has resulted in an additional general research question, namely how systems that are linear, except for small but significant non-linear parts, can be simulated in an efficient way. Another specific result is a validated real-time virtual machine concept for simulation of the water jet cutting machine, which facilitates early-stage design optimisation. As the mechanics and the control system are considered simultaneously, interaction effects can be utilised. An introductory optimisation study shows a significant potential for improved manufacturing accuracy and a more light-weight design. This potential would not likely have been found through a conventional sequential design approach. The results of this thesis indicate that there is a great potential for improved product development performance in small and medium-sized companies. By incorporating modern simulation support these companies can improve their competitiveness as well as contribute to improved resource efficiency of society at large. In doing so, it is important to find a good balance between model fidelity, validity and cost for achieving a relevant decision support. The coordinated approach to simulation-driven design elaborated in this thesis is a promising and systematic way of finding this balance.

  • 285. Wall, Johan
    et al.
    Englund, Thomas
    Ahlin, Kjell
    Broman, Göran
    Influence of a bellows-type flexible joint on exhaust system dynamics2004Inngår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering, ISSN 0954-4070, E-ISSN 2041-2991, Vol. 218, nr 12, s. 1473-1478Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Most modern cars have a bellows-type flexible joint between the manifold and the catalytic converter to allow for thermal expansion and to decouple large engine movements and vibrations from the rest of the exhaust system. To obtain better understanding of the influence of this joint, the dynamic response of a typical exhaust system is studied when excited via different joint configurations. Measurements show the great order of reduction of vibration transmission to the exhaust system that a bellows joint, with and without an inside liner, gives in comparison with a stiff joint. For the combined bellows and liner joint vibration transmission is however higher than for the bellows alone. Together with some other aspects this makes the choice of including a liner in the exhaust system application complex. For a system in general the possibility of tuning the friction limit of the liner, to minimise overall vibrations through friction based damping, depends on how close to ideal the excitation source is and its location. Anyhow, the combined bellows and liner joint makes the exhaust system behaviour significantly non-linear, whereas the system behaviour proves to be essentially linear when the bellows has no liner, which imply that the liner needs to be included in theoretical models when present in the real system.

  • 286. Wall, Johan
    et al.
    Englund, Thomas
    Ahlin, Kjell
    Broman, Göran
    Modelling of multi-ply bellows flexible joints of variable mean radius2003Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Bellows flexible joints are included in automobile exhaust systems to allow for engine movements and thermal expansion and to reduce vibration transmission. Generally the joint consists of a flexible bellows, an inside liner and an outside braid. In this work the bellows is considered. A straightforward way to model the bellows is to use shell finite elements. Due to the convoluted geometry of the bellows that procedure requires however a high number of elements, meaning that the bellows model would constitute a large part of the model of the exhaust system. For more effective dynamics simulations a beam finite element representation of the bellows has been presented in a prior work. This modelling procedure was implemented in the commercial software I-DEAS and was verified against experimental results available in the literature for single-ply bellows of constant mean radius. This paper suggests adjustments by which this procedure can be extended to model also multi-ply bellows of variable mean radius. Experimental investigations of a double-ply bellows having decreasing mean radius towards its ends are included for verification. The agreement between theoretical and experimental results is very good, implying that the suggested extension of the modelling procedure is valid. It is also shown that the procedure can easily be implemented into other commercial software (in this case ABAQUS). The experimental investigation reveals an intriguing resonance frequency shift at small excitation force levels. Although considered to be of minor significance for the present application of the bellows, a hypothetic qualitative explanation to the observed phenomenon is given.

  • 287. Wall, Johan
    et al.
    Englund, Thomas
    Berghuvud, Ansel
    Identification and Modelling of Structural Dynamics Characteristics of a Water Jet Cutting Machine2004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Dynamic characteristics of a water jet cutting machine, to be used in a virtual machine implemented in an analysis tool for engineering design, are derived. Machine users need for more cost effective production put demands on faster cutting. Faster cutting results in higher dynamic loads. As a consequence, problems with unwanted vibrations that decrease cutting precision may occur. Prediction of such potential problems is facilitated by an analysis tool for evaluation of suggested design solutions early in the product development process. The present work contributes to ongoing development of such an analysis tool for design engineers. An iterative approach including both theoretical and experimental analysis is applied in order to derive a structural dynamics model of the studied machine. A complex dynamic behaviour of the machine is found. High correlation between results obtained from theoretical and experimental modal analysis implies that the developed model can be used with confidence in future studies of the machine’s total system behaviour.

  • 288. Wallin, Johanna
    et al.
    Chirumalla, Koteshwar
    Thompson, Anthony
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Developing PSS Concepts from Traditional Product Sales Situation: The Use of Business Model Canvas2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In recent years there has been growing interest in utilizing a product-service system (PSS) approach when developing products and services in order to arrive at a business model focused on selling function or availability instead of physi-cal products. However, the complex nature of PSS development has left many manufacturers still struggling to arrive at PSS concepts out of their traditional product sales situation in early design phases. The purpose of this paper is to propose an approach using the Business Model Canvas which could help manufacturers in the transition towards PSS development by articulating key business elements in developing and analyzing PSS concepts evolving from their traditional product sales situation. The paper presents preliminary findings from the aerospace industry and discusses the evolution of key business elements for PSS concepts from traditional product sales situation using the Business Model Canvas. Finally, the potential benefits of using the Business Model Canvas in a PSS context are discussed.

  • 289.
    Weiber, Ingrid
    et al.
    Blekinge Tekniska Högskola, Fakulteten för hälsovetenskaper, Institutionen för hälsa.
    Tengland, Per-Anders
    Berglund, Johan
    Blekinge Tekniska Högskola, Fakulteten för hälsovetenskaper, Institutionen för hälsa.
    Eklund, Mona
    Social and Healthcare Professionals' Experiences of Giving Support to Families Where the Mother Has an Intellectual Disability: Focus on Children2014Inngår i: Journal of Policy and Practice in Intellectual Disabilities, ISSN 1741-1122 , Vol. 11, nr 4, s. 293-301Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Families where the mother has an intellectual disability need support to counteract possible detrimental life circumstances for the children involved. The aim of this study was to describe social and healthcare professionals' experiences of providing support for families with maternal intellectual disability and specifically focused on if and how they believed the support practices benefited the children. Seven focus group interviews were performed with 29 professional informants. The transcripts were analyzed with qualitative content analysis. Three themes were identified: support practices, pedagogical strategies when supporting families with maternal intellectual disability, and maintaining the child perspective. The support practices mainly dealt with parenting skills, which were addressed by a variety of teaching methods and practices, while the children were at risk of not being seen or heard.

  • 290. Winberg, Mathias
    Speech Enhancement and Noise Combat1999Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 291. Winberg, Mathias
    et al.
    Hansen, Colin
    Claesson, Ingvar
    Li, Xun
    Active Control of Engine Vibrations in a Collins Class Submarine2003Rapport (Annet vitenskapelig)
    Abstract [en]

    Submarine manufacturers invest considerable effort and money in improving the attenuation of noise radiated by submarines into the water. A number of different noise sources contribute to the total acoustic signature on an advanced submarine, such as the Collins Class. This report focuses on the problem associated with low order harmonics generated by the main diesel engines, transmitted through the engine mounts into the hull, and subsequently radiating into the water. The diesel engine mount consists of a two stage isolation system with a large intermediate mass, weighing approximately $500$ kg. Each engine is attached to the hull by eight mounts. The main intention of the work described here is to experimentally investigate the use of active vibration control to minimize the vibratory energy of the intermediate mass in all six degrees of freedom, thereby also minimizing the vibratory energy transmitted to the hull. This approach involves the use of seven inertial actuators, mounted on the intermediate mass, to produce the cancelling vibration field. A test rig, similar to one of the diesel engine mounts on the actual submarine, was constructed in the laboratory at The University of Adelaide and used for the real-time active control experiments described here. Several different set-ups were evaluated using primary vibrations with the same absolute levels and frequency content as measured on board a Collins class submarine. The controller used in the real-time experiments is based on the filtered X-LMS algorithm, which is a feed-forward algorithm working in the time domain.It is demonstrated here that active vibration control of the intermediate mass of the existing diesel engine mounts is a practical way of reducing the 1.0, 1.5 and 2.0 engine order components in the noise spectrum radiated as a result of vibration transmission through the engine mounts.

  • 292. Winberg, Mathias
    et al.
    Johansson, Sven
    Claesson, Ingvar
    Inertial Mass Actuators, Understanding and Tuning1994Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The actuators, the error sensors and the control system are central components in active noise and vibration control systems. The actuators produce the secondary forces acting on the structure while the error sensors measure the quantity to be minimized. Inertial mass actuators are used frequently in a variety of applications, e.g. boat engine mounts and airplane fuselages. To tune the inertial mass actuator to fit a certain application or just to understand the manufactures specification it is important to have an understanding of the construction of the actuator and the equations describing it. This paper presents a mathematical model of the mechanical and electrical system for the inertial mass actuator. A mobility analogy is introduced in order to determine how the inertial mass and the spring constant of the suspension effect the resonance frequency of the actuator as well as the output force. Does the mobility of the structure, the actuator is mounted on, effect the produced output force inrelationship to the rated force of the actuator? Practical measurement results are presented in order to determine the resonance frequency and output forceof an inertial mass actuator manufactured by Metravib in France.

  • 293. Winberg, Mathias
    et al.
    Lagö, Thomas L
    Inertial Mass Active Mounts Used in a Marine Application1999Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Different actuators have been developed for active noise cancellation. For volumetric applications, a loudspeaker is usually used. When the noise is induced by engines it may be more efficient to work on the noise source itself, the engine vibration. In this case it is important to have an actuator that can counteract the vibration, not the sound field. In the research project AVIIS (Active Vibration Isolation In Ships), such an actuator has been developed. The actuator is an electrodynamic, inertial mass type shaker, designed and tuned for this project. The boat used in these experiments is a Storebro Royal Cruiser 33, powered by two Volvo Penta TAMD engines. Each engine is mounted to the hull in four points. Prior research, \cite{thomas1} shows that the main transmission paths for the vibrations from the engine and the propeller to the hull, are through these mounting points. Once the hull is excited, a lot of sound and annoying noise is produced in the cabin. The main idea is to isolate these vibrations from the hull by adding a combined active and passive engine mount that will control the vibrations by minimizing the sound field in the cabin using microphones as error sensors, a so called ASAC (Active Structural Acoustic Control) approach.

  • 294. Yang, Geng
    et al.
    Li, Xie
    Mäntysalo, Matti
    Zhou, Xiaolin
    Pang, Zhibo
    Xu, Li Da
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Chen, Qiang
    Zheng, Lirong
    A Health-IoT Platform Based on the Integration of Intelligent Packaging, Unobtrusive Bio-Sensor and Intelligent Medicine Box2014Inngår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 10, nr 4, s. 2180-2191Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In-home healthcare services based on the Internet-of-Things (IoT) have great business potential; however, a comprehensive platform is still missing. In this paper, an intelligent home-based platform, the iHome Health-IoT, is proposed and implemented. In particular, the platform involves 1) an open-platform-based intelligent medicine box (iMedBox) with enhanced connectivity and interchangeability for the integration of devices and services, 2) intelligent pharmaceutical packaging (iMedPack) with communication capability enabled by passive radio-frequency identification (RFID) and actuation capability enabled by functional materials, and 3) flexible and wearable bio-medical sensor device (Bio-Patch) enabled by the state-of-the-art inkjet printing technology and system-on-chip. The proposed platform seamlessly fuses IoT devices (e.g., wearable sensors, intelligent medicine packages, etc.) with in-home healthcare services (e.g., telemedicine) for an improved user experience and service efficiency. The feasibility of the implemented iHome Health-IoT platform has been proven in field trials.

  • 295. Yang, Kai
    et al.
    Mfoumou, Etienne
    Kao-Walter, Sharon
    Chi, Yilin
    Experimental Study of Packaging Materials Based on Acoustic Measurements Combined with Tensile Tests2009Rapport (Annet vitenskapelig)
    Abstract [en]

    In this report, we investigated the variation between tension and fundamental frequency with respect to time, and at a constant strain rate. This was done for rectangular thin sheets under uniaxial tensile test and transverse vibration. Thin Paper (PPR), Low Density Polyethylene (LDPE) and laminate (PPR/LDPE/Al-foil) sheets were analyzed both within the elastic and plastic (which was investigated in this work) regions. The emphasis is on the linear relationship between the resonance frequency (in square) and the load.

  • 296.
    Yang, Peng
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Investigating aluminum plate with different geometrical shape by using DIC tension test2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This subject mainly uses Aluminum sheet metal material as the research object which is used in Volvo XC90 door, the elastic plasticity deformation within the different material angles and notch shape investigated with MTS tensile test equipment under uniaxial tension. The local strain curve studied by using DIC method to obtain the conventional physical quantity. Combining ABAQUS to analyze the distribution of stress in elastic and plastic regions, also use MATLAB to combine various parameters, and finally analyze the desired experimental results to find a relatively stable notch shape based on the yield curve and stress concentration factor.

  • 297.
    Zachén, Esbjörn
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Extraction of tool reaction forces using LS-DYNA and its use in Autoform sheet metal forming simulation2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In product development there is still potential to decrease lead times with faster and more accurate simulations. The objective of this thesis was to study whether Finite Element (FE) simulations using explicit LS-DYNA to extract reaction forces from sheet metal forming tools during forming, could be used to improve existing FE models in sheet metal forming software AutoForm.To begin with, the solid CAD-model of the stamping dies were meshed with tetrahedral elements in CATIA and imported into LS-DYNA. In combination with sheet mesh and milling surface meshes from AutoForm, an explicit model was realized. Contacts between sheet mesh and milling surface meshes used the so-called sheet forming contact. The resulting reaction forces were extracted and used in a simulation using the AutoForm software. Resulting simulation was compared to a scan of the physical sheet metal after forming.The direct transfer of reaction forces from LS-DYNA to AutoForm did however not result in the same pressure distribution in AutoForm. The AutoForm simulations using results from LS-DYNA were slightly worse than standard AutoForm simulations.Further work is needed to try and perhaps implement an implicit solution after an initial explicit solution.

  • 298.
    Zhang, Defeng
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Development of Numerical  Research Tool  to Explore the Mechanism of Necking and Delamination in Packaging Materials2015Annet (Annet vitenskapelig)
    Abstract [en]

    Necking and delamination, appear due to loading in packaging materials, consisting of LDPE, Al-foil, adhesive layer, etc. These have significant negative influence on properties of packaging materials. However, how the mechanism influences is still unclear enough and there is no appropriate research tool available to study it.

    We are intend to develop an FEM model about it. It will work as a robust numerical analysis tool for further research.

  • 299.
    Zhang, Defeng
    et al.
    College of Mech. Eng., Quzhou University, 324000 Quzhou, China.
    Mao, Kunming
    Dassault Systemes SIMULIA Corp, West Lafayette, Indiana, USA.
    Islam, Md. Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Andreasson, Eskil
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik. Tetra Pak Packaging Solutions AB.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik. Fac. of Mech. & El. Eng., Shanghai Second Polytechnic Univ., 201209 Shanghai, China.
    Powerful Modelling Techniques in ABAQUS to Simulate Failure of Laminated composites2016Rapport (Fagfellevurdert)
    Abstract [en]

    In this study, laminated composites consisting of LDPE (Low Density Polyethylene), Al-foil (Aluminum foil)and an adhesive interface layer is focused. The defects like necking in LDPE, Al-foil layer and interfacial delaminationcan significantly impact the loading capacity of the laminated material. However, the influence mechanisms of thedefects are still unclear, and no appropriate research tool is available. Therefore, the FEM model based on alreadyavailable techniques in ABAQUS is developed in this work. The aim with the model is to create a robust numericalanalysis tool for further research work.In the modelling process, possibility of necking in substrates and interfacial delamination between material layers isconsidered. A coupled elasto-plasticity damage constitutive model, based on Hooke’s Law, the J2 yield criterion,isotropic hardening, associated flow-rule and ductile damage model, is formulated to demonstrate necking behaviorof substrates. In ABAQUS, three modelling techniques, namely VCCT, Cohesive Element, and XFEM, have been usedto simulate interfacial delamination. The simulation results are compared with the theoretical results.A uniaxial tension test consisting of a two material laminate is simulated by using these three modelling techniques.The special modelling skills for respective modelling techniques, element type, meshing technique of each model, arealso introduced. The comparison with the theoretical results shows necking in substrates and interfacial delaminationare also achieved in all three models as expected. Deformation results of the simulation are very close to that of thetheoretical analysis. Technique features of VCCT, Cohesive Element and XFEM in modelling of interfacialdelamination are analyzed and concluded. These three FEM models can all be utilized according to the requirementsof subsequent research.

  • 300.
    Zhang, Defeng
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Mao, Kunming
    Dassault Systemes SIMULIA Corp.
    Islam, Md. Shafiqul
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Andreasson, Eskil
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Mehmood, Nasir
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Powerful Modelling Techniques in Abaqus to Simulate Necking and Delamination of Laminated Composites2015Annet (Annet vitenskapelig)
    Abstract [en]

    In this study, laminated composites consisting of LDPE (Low Density Polyethylene), Al-foil (Aluminum foil) and an adhesive interface layer is focused. The defects like necking in LDPE, Al-foil layer and interfacial delamination can significantly impact the loading capacity of the laminated material. However, the influence mechanisms of the defects are still unclear, and no appropriate research tool is available. Therefore, the FEM model based on already available techniques in ABAQUS is developed in this work. The aim with the model is to create a robust numerical analysis tool for further research work.

    In the modeling process, possibility of necking in substrates and interfacial delamination between material layers is considered. The constitutive material behaviour is elastic-plastic complemented with progressive damage, based on Hooke’s Law, the J2 yield criterion, isotropic hardening, associated flow-rule and ductile damage model are formulated to demonstrate necking behavior of substrates. In ABAQUS, three modeling techniques, namely VCCT, Cohesive Element, and XFEM, have been used to simulate interfacial delamination. The simulation results are compared with the theoretical results.

    A uniaxial tension test consisting of a two material laminate is simulated by using these three modeling techniques. The special modelling skills for respective modeling techniques, element type, meshing technique of each model, are also introduced. The comparison with the theoretical results shows necking in substrates and interfacial delamination are also achieved in all three models as expected. Deformation results of the simulation are very close to that of the theoretical analysis. Technique features of VCCT, Cohesive Element and XFEM in modelling of interfacial delamination are analyzed and concluded. These three FEM models can all be utilized according to the requirements of subsequent research.

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