Change search
Refine search result
1234567 51 - 100 of 318
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 51.
    Byggeth, Sophie
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Ny, Henrik
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Wall, Johan
    Broman, Göran
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Robèrt, Karl-Henrik
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Introductory Procedure for Sustainability-Driven Design Optimization2007Conference paper (Refereed)
    Abstract [en]

    In response to the increasingly competitive global market, there is a growing interest in design optimization. Being able to include aspects of socio-ecological sustainability in product design should aid companies to both improve current competitiveness and to identify viable long-term investment paths and new business opportunities in the evolving sustainability-driven market. A case study of a water jet cutting machine is used to illustrate a new iterative optimization procedure that combines a technical assessment with a sustainability assessment. Sustainability assessment methods/tools are first used to identify prominent sustainability problems from present-day flows and practices (“societal indicators”) and to generate ideas of long-term solutions and visions. Based on this, preliminary ideas about likely desirable changes in machine properties are obtained. Technical investigations are then performed to assess if/how these particularly desirable changes in machine properties could in principle be realized through changes in design variables. After that, obtainable changes are fed back to a new and more refined sustainability assessment to find out the societal implications of these changes. This may in turn result in other desirable design changes, which may call for a new and more refined technical assessment, etcetera. The experience from the case study indicates that the suggested integrated and iterative working procedure should be able to add information about socio-ecological impacts of product properties and influence design criteria used in prioritisation situations during product development.

  • 52. Chen, S.H.
    et al.
    Wang, Tzuchiang
    Kao-Walter, Sharon
    A crack perpendicular to a bimaterial interface an interface in finite solid2003In: International Journal of Solids and Structures, ISSN 0020-7683 , Vol. 40, no 11, p. 2731-55Article in journal (Refereed)
    Abstract [en]

    The dislocation simulation method is used in this paper to derive the basic equations for a crack perpendicular to the bimaterial interface in a finite solid. The complete solutions to the problem, including the T stress and the stress intensity factors are obtained. The stress field characteristics are investigated in detail. It is found that when the crack is within a weaker material, the stress intensity factor is smaller than that in a homogeneous material and it decreases when the distance between the crack tip and interface decreases. When the crack is within a stiffer material, the stress intensity factor is larger than that in a homogeneous material and it increases when the distance between the crack tip and interface decreases. In both cases, the stress intensity factor will increase when the ratio of the size of a sample to the crack length decreases. A comparison of stress intensity factors between a finite problem and an infinite problem has been given also. The stress distribution ahead of the crack tip, which is near the interface, is shown in details and the T stress effect is considered.

  • 53. Chen, S.H.
    et al.
    Wang, Tzuchiang
    Kao-Walter, Sharon
    Finite boundary effects in problem of a crack perpendicular to and terminating at a bimaterial interface2005In: Acta Mechanica Sinica, ISSN 0567-7718 (p)1614-3116(online), Vol. 21, no 1, p. 56-64Article in journal (Refereed)
    Abstract [en]

    The problem of a crack perpendicular to and terminating at an interface in bimaterial structure with finite boundaries is investigated. The dislocation simulation method and boundary collocation approach are used to derive and solve the basic equations.Two kinds of loading form are considered when the crack lies in a softer or a stiffer material, one is an ideal loading and the other one fits to the practical experiment loading. Complete solutions of the stress field including the T stress are obtained as well as the stress intensity factors. Influences of T stress on the stress field ahead of the crack tip are studied. Finite boundary effects on the stress intensity factors are emphasized. Comparisons with the probled presented by Chen et al. (int. J. Solids and Structure, 2003,40, 2731-2755) are discussed also.

  • 54. Chirumalla, Koteshwar
    et al.
    Bertoni, Alessandro
    Aditya, Aditya
    Johansson, Christian
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Bertoni, Marco
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Performance measurement framework for product-service systems development: a balanced scorecard approach2013In: International Journal of Technology Intelligence and Planning (IJTIP), ISSN 1740-2832, E-ISSN 1740-2840, Vol. 9, no 2, p. 146-164Article in journal (Refereed)
    Abstract [en]

    The paper proposes a framework for analysing the performances of product-service systems (PSSs) development processes using a balanced scorecard (BSC) as an instrument to guide the implementation and the evaluation of new methods and tools. Emerging from a case study in the aerospace industry, the paper discusses the main challenges in PSS development and proposes a performance measurement framework for PSS development based on multi-criteria indicators. Finally, the benefits of a framework for PSS development performance measurement are discussed.

  • 55. Chirumalla, Koteshwar
    et al.
    Bertoni, Alessandro
    Parida, Aditya
    Johansson, Christian
    Bertoni, Marco
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Performance Measurement Framework for Product-Service System Development: A Balanced Scorecard Approach2013In: International Journal of Technology Intelligence and Planning (IJTIP), ISSN 1740-2832, E-ISSN 1740-2840, Vol. 9, no 2, p. 146-164Article in journal (Refereed)
    Abstract [en]

    The Product-Service System (PSS) paradigm is recognized as a means for companies to increase the value perceived by the customers, thus gaining competitive advantage beyond traditional ‘pure product’ offerings. Researches have shown the necessity to rethink design processes in a PSS context, in order to drive the successful integration of product and service features in early design phases. In the last few years, several new approaches have been proposed, however little attention has been paid on how to translate these approaches into action and on how to evaluate their performances and effectiveness. This paper proposes a framework for analysing the performances in PSS development process using a Balanced Scorecard approach, as a tool to guide the implementation and the evaluation of new methods and tools in the early design phases. The paper starts with discussing the main challenges encountered when designing PSS, and then, adopting an aerospace industry as an example, to propose an application of the Balance Scorecard for the implementation and measurement of PSS development. Finally, the main pros and cons are discussed in relation to strengths and weaknesses of using balanced scorecard in PSS development. The framework developed in this paper can provide a useful guidance for the managers in measuring the performances of the PSS development process.

  • 56. Demin, I.Yu.
    et al.
    Pronchatov-Rubtsov, N.V.
    Rudenko, Oleg
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Gurbatov, S.N.
    Krainov, A.
    The numerical simulation of propagation of intensive acoustic noise2013Conference paper (Refereed)
    Abstract [en]

    The propagation of intensive acoustic noise is of fundamental interest in nonlinear acoustics. Some of the simplest models describing such phenomena are generalized Burgers’ equations for finite amplitude sound waves. An important problem in this field is to find the wave’s behavior far from the emitting source for stochastic initial waveforms. The method of numerical solution of generalized Burgers equation proposed is step-by-step calculation supported on using Fast Fourier Transform of the considered signal. The general idea is to keep only Fourier image of concerned signal and update it recursively (in space). For simulating the wave evolution we used 4096 (212) point realizations and took averaging over 1000 realizations. Also the object of the present study is a numerical analysis of the spectral and bispectral functions of the intense random signals propagating in nondispersive nonlinear media. The possibility of recovering the input spectrum from the measured spectrum and bispectrum at the output of the nonlinear medium is discusses. The analytical estimations are supported by numerical simulation. For two different types of primary spectrum evolution of jet noise were numerically simulates at a short distance and assayed bispectrum and a spectrum analysis of the signals.

  • 57. Dziak, D. M.
    et al.
    Jachimczyk, B. S.
    Kulesza, Wlodek
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    An Analysis of Uncertainty and Robustness of Waterjet Machine Positioning Vision System2013In: Elektronika Ir elektrotechnika, ISSN 1392-1215, Vol. 19, no 9, p. 89-92Article in journal (Refereed)
    Abstract [en]

    The paper presents a new Automatic Waterjet Positioning Vision System (AWPVS) and investigates components of workpiece positioning accuracy. The main purpose of AWPVS is to precisely identify the position and rotation of a workpiece placed on a waterjet machine table. Two webcams form a basis for the system, and constitute its characteristics. The proposed algorithm comprises various image processing techniques to assure a required identification precision. To validate the PVS identification quality, synthetic images were applied under various conditions. The analysis ascertains dependence of an object detection rate and accuracy on a size of cropping frame. Experimental results of the proposed PVS prototype prove that a combination of the vision algorithm and webcams is an alternative to dedicated expensive industrial vision systems. The two main components of AWPVS uncertainty, a machine component and PSV component are discerned and estimated.

  • 58. Emam, Seyed Mohammad
    et al.
    Khatibi, Siamak
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Khalili, Khalil
    Improving the Accuracy of Laser Scanning for 3D Model Reconstruction Using Dithering Technique2014In: Procedia Technology / [ed] Moldovan, L, Elsevier , 2014, Vol. 12Conference paper (Refereed)
    Abstract [en]

    Triangulation technique is one of the most commonly techniques used in three dimensional measurements. Depth reconstruction accuracy is a direct impact of the quantization process and this is related to the number of pixels of the sensor. Dithering technique (DT) benefits from relative fine movement between object and sensor to reduce the quantization error. This paper describes the theory of the DT and establishes a mathematical model. To evaluate if DT technique can improve the accuracy in real world, a control rig was designed and built, following which experiments were performed. The results showed that considerable improvement can be achieved in measurement accuracy.

  • 59. Enflo, Bengt
    et al.
    Hedberg, Claes
    A Standing Acoustic Wave with Shocks in a Cubically Nonlinear Medium2008Conference paper (Refereed)
    Abstract [en]

    It is well known that transversal elastic waves in homogeneous solids satisfy a wave equation with a cubic nonlinearity. This equation with resonator boundary conditions can be transformed into a functional equation, which can be reduced to a second order partial differential equation with a cubic nonlinearity. From this equation, by specializing to steady state and integrating one step, we obtain a first order ordinary differential equation with three terms in addition to the derivative: a cubic and a linear term in the dependent variable and a known term (sinus). The coefficient of the derivative is proportional to the dissipation and assumed to be small. Among several cases the most complicated case, the coefficient of the linear term lying between zero and (0.5)(2/3)=0.63, is treated in this paper. In each period the solution has two shocks. At one side of each shock it is necessary to introduce an intermediate boundary layer between the outer region and the inner region next to the shock. The intermediate solution is matched both outwards and inwards. The actual first order ordinary differential equation is also solved numerically both in the outer region and in the neighborhood of the shocks. © 2008 American Institute of Physics.

  • 60. Enflo, Bengt
    et al.
    Hedberg, Claes
    Fourier decomposition of a plane nonlinear sound wave and transition from Fubini´s to Fay´s solution of Burger´s equation1999Conference paper (Refereed)
    Abstract [en]

    Burgers' equation describes plane sound wave propagation through a thermoviscous fluid. If the boundary condition at the sound source is given as a pure sine wave, the exact solution is given by the Cole-Hopf transformation as a quotient between two Fourier series. Two approximate Fourier series representations of this solution are known: Fubini's (1935) solution, neglecting dissipation and valid at short distance from the sound source, and Fay's (1931) solution, valid far from the source. In the present investigation a linear system of equations is found, from which the coefficients in a series expansion of each Fourier coefficient can be derived one by one. Curves which join smoothly to Fubini's solution (valid up to slightly before shock formation) and to Fay's solution (valid for approximately three shock formation distances). Maxima for the Fourier coefficients of the higher harmonics are given. These maxima are situated in a region where neither Fubini's nor Fay's solution is valid.

  • 61. Enflo, Bengt
    et al.
    Hedberg, Claes
    Fourier decomposition of a plane nonlinear sound wave developing from a sinusoidal source2001In: Acustica, ISSN 0001-7884, Vol. 87, no 2, p. 163-169Article in journal (Refereed)
    Abstract [en]

    Burgers' equation describes plane sound wave propagation through a thermoviscous fluid. If the boundary condition at the sound source is given as a pure sine wave, the exact solution given by the Cole-Hopftransformation is a quotient between two Fourier series. Two approximate Fourier series representations of this solution are known: Fubini's (1935) solution, neglecting dissipation and valid at short distance from the sound source, and Fay's solution, valid far from the source. In the present investigation a linear system of equations is found, from which the coefficients in a series expansion of each Fourier coefficient can be derived one by one. Curves which join smoothly to Fubini's solution (valid up to slightly before shock formation) and to Fay's solution (valid for approximately three shock formation distances). Maxima for the Fourier coefficients of the higher harmonics are given. These maxima are situated in a region where neither Fubini's nor Fay's solution is valid.

  • 62. Enflo, Bengt
    et al.
    Hedberg, Claes
    Theory of Nonlinear Acoustics in Fluids2002Book (Other academic)
    Abstract [en]

    This book presents theoretical nonlinear acoustics in fluids with equal stress on physical foundations and mathematical methods. From first principles in fluid mechanics and thermodynamics a universal mathematical model (Kuznetsov's equation) of nonlinear acoustics is developed. This model is applied to problems such as nonlinear generation of higher harmonics and combination frequencies, the shockwave from a supersonic projectile, propagation of shocks in acoustic beams and nonlinear standing waves in resonators. Special for the book is the coherent account of nonlinear acoustic theory from a unified point of view and the detailed presentations of the mathematical techniques for solving the nonlinear acoustic model equations. The book differs from mathematical books on nonlinear wave equations by its stress on their origin in physical principles and their use for physical applications. It differs from books on applications of nonlinear acoustics by its ambition to explain all steps in mathematical derivations of physical results. It is useful for practicians and researchers in acoustics feeling the need for more theoretical understanding. It can be used as a textbook for graduate or advanced undergraduate students with an adequate background in physics and mathematical analysis, specializing in acoustics, mechanics or applied mathematics. See also http://www.wkap.nl/prod/b/1-4020-0572-5.

  • 63. Enflo, Bengt
    et al.
    Hedberg, Claes
    Rudenko, Oleg
    Nonlinear standing waves in a closed tub2002Conference paper (Refereed)
    Abstract [en]

    Simplified nonlinear evolution equations describing nonsteady-state forced vibrations in an acoustic resonator having one closed end and the other end periodically oscillating are derived. An approach is used based on a nonlinear functional equation. This approach is shown to be equivalent to the version of the successive approximation method developed in 1964 by Chester. It is explained how the acoustic field in the cavity is described as a sum of counterpropagating waves with no cross-interaction. The nonlinear Q-factor and the nonlinear frequency response of the resonator are calculated for steady-state oscillations of both inviscid and dissipative media. The general expression for the mean intensity of the acoustic wave in terms of the characteristic value of a Mathieu function is derived. Some results from a perturbation calculation of the wave profile are given.

  • 64. Enflo, Bengt
    et al.
    Hedberg, Claes
    Rudenko, Oleg
    Resonant properties of a nonlinear dissipative layer excited by a vibrating boundary: Q-factor and frequency response2005In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 117, no 2, p. 601-612Article in journal (Refereed)
    Abstract [en]

    Simplified nonlinear evolution equations describing non-steady-state forced vibrations in an acoustic resonator having one closed end and the other end periodically oscillating are derived. An approach based on a nonlinear functional equation is used. The nonlinear Q-factor and the nonlinear frequency response of the resonator are calculated for steady-state oscillations of both inviscid and dissipative media. The general expression for the mean intensity of the acoustic wave in terms of the characteristic value of a Mathieu function is derived. The process of development of a standing wave is described analytically on the base of exact nonlinear solutions for different laws of periodic motion of the wall. For harmonic excitation the wave profiles are described by Mathieu functions, and their mean energy characteristics by the corresponding eigenvalues. The sawtooth-shaped motion of the boundary leads to a similar process of evolution of the profile, but the solution has a very simple form. Some possibilities to enhance the Q-factor of a nonlinear system by suppression of nonlinear energy losses are discussed. (C) 2005 Acoustical Society of America.

  • 65. Enflo, Bengt
    et al.
    Hedberg, Claes
    Rudenko, Oleg
    Standing and propagating waves in cubically nonlinear media2006In: Proceedings of the International Conference Mathematical Modelling / [ed] Nilsson, Börje, American Institute of Physics , 2006, p. 187-195Chapter in book (Other academic)
    Abstract [en]

    The paper has three parts. In the first part a cubically nonlinear equation is derived for a transverse finite-amplitude wave in an isotropic solid. The cubic nonlinearity is expressed in terms of elastic constants. In the second part a simplified approach for a resonator filled by a cubically nonlinear medium results in functional equations. The frequency response shows the dependence of the amplitude of the resonance on the difference between one of the resonator's eigenfrequencies and the driving frequency. The frequency response curves are plotted for different values of the dissipation and differ very much for quadratic and cubic nonlinearities. In the third part a propagating N-wave is studied, which fulfils a modified Burgers' equation with a cubic nonlinearity. Approximate solutions to this equation are found for new parts of the wave profile.

  • 66. Enflo, Bengt
    et al.
    Rudenko, Oleg
    Hedberg, Claes
    Nonlinear Standing Waves in a Layer Excited by the Periodic Motion of its Boundary2002Conference paper (Refereed)
    Abstract [en]

    Simplified nonlinear evolution equations describing nonsteady-state forced vibrations in an acoustic resonator having one closed end and the other end periodically oscillating are derived. An approach is used based on a nonlinear functional equation. This approach is shown to be equivalent to the version of the successive approximation method developed in 1964 by Chester. It is explained how the acoustic field in the cavity is described as a sum of counterpropagating waves with no cross-interaction. The nonlinear Q-factor and the nonlinear frequency response of the resonator are calculated for steady-state oscillations of both inviscid and dissipative media. The general expression for the mean intensity of the acoustic wave in terms of the characteristic value of a Mathieu function is derived. The process of development of a standing wave is described analytically for three different types of periodic motion of the wall: harmonic excitation, sawtooth-shaped motion and "inverse saw motion".

  • 67. Englund, Thomas
    Dynamic characteristics of automobile exhaust system components2003Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Demands on emission control, and low vibration and noise levels have made the design of automobile exhaust systems a much more complex task over the last few decades. This, combined with increasing competition in the automobile industry, has rendered physical prototype testing impractical as the main support for design decisions. The aim of this thesis is to provide a deeper understanding of the dynamic characteristics of automobile exhaust system components to form a basis for improved design and the development of computationally inexpensive theoretical component models. Modelling, simulation and experimental investigation of a typical exhaust system are performed to gain such an understanding and evaluate ideas of component modelling. Modern cars often have a gas-tight bellows-type flexible joint between the manifold and the catalytic converter. This joint is given special attention since it is the most complex component from a dynamics point of view and because it is important for reducing transmission of engine movements to the exhaust system. The joint is non-linear if the bellows consists of multiple plies or if it includes an inside liner. The first non-linearity is shown to be weak and may therefore be neglected. The non-linearity due to friction in the liner is, however, highly significant and gives the joint complex dynamic characteristics. This is important to know of and consider in exhaust system design and proves the necessity of including a model of the liner in the theoretical joint model when this type of liner is present in the real joint to be simulated. It is known from practice and introductory investigations that also the whole system sometimes shows complex dynamic behaviour. This can be understood from the non-linear characteristics of the flexible joint shown in this work. An approach to the modelling of the combined bellows and liner joint is suggested and experimentally verified. It is shown that the exhaust system is essentially linear downstream of this joint. Highly simplified finite element models of the 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 5 and the experimental results is very good, which verifies the usability of these component models. A major conclusion is that in coming studies of how engine vibrations affect the exhaust system it 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 sub-system that is excited via a non-linear joint.

  • 68. Englund, Thomas
    et al.
    Wall, Johan
    Ahlin, Kjell
    Broman, Göran
    Automated updating of simplified component models for exhaust system dynamics simulations2002Conference paper (Refereed)
    Abstract [en]

    To facilitate overall lay-out optimisation simplified component models for dynamics simulations of automobile exhaust systems are desired. Such optimisation could otherwise be computationally expensive, especially when non-linear analyses are necessary. Suggestions of simplified models of the mufflers and the catalyst are given. To account for the flexibility at the connections between those components and the pipes short beam elements with individual properties are introduced at these locations. An automated updating procedure is developed to determine the properties of these beam elements. Results from an experimental modal analysis are used as the reference. The theoretical model of the exhaust system is built in the finite element software ABAQUS. The updating procedure uses the sequential quadratic programming algorithm included in the Optimization Toolbox of the software MATLAB to minimise the sum of the differences between experimentally and theoretically obtained natural frequencies. Constraints are used on the correlation between the experimentally and theoretically obtained mode shapes by considering the MAC-matrix. Communication between the two software packages is established by an in-house MATLAB script. The correlation between results from the updated theoretical model and the experimental results is very good, which indicates that the updating procedure works well.

  • 69. Englund, Thomas
    et al.
    Wall, Johan
    Ahlin, Kjell
    Broman, Göran
    Dynamic characteristics of a combined bellows and liner flexible joint2004In: Journal of Automobile Engineering, ISSN 0954-4070 , Vol. 218, no 5, p. 485-493Article in journal (Refereed)
    Abstract [en]

    A bellows combined with an inside liner and an outside braid is commonly used as a flexible joint in automobile exhaust systems to reduce transmission of engine movements to the exhaust system. It greatly influences the dynamics of the complete system. Understanding of its dynamic characteristics and a modelling method that facilitates systems simulation are therefore desired. This has been obtained in earlier works for the bellows itself. In this work an approach to the modelling of the combined bellows and liner joint is suggested and experimentally verified. Simulations and measurements show that the liner adds significant non-linearity and makes the characteristics of the joint complex. Results are presented for the axial and the bending load cases. In torsion, influence of the liner is negligible. Peak responses are significantly reduced when the excitation level approximately corresponds to the friction limit of the liner. The complexity of the combined bellows and liner joint is important to know of and consider in exhaust system design and proves the necessity of including a model of the liner in the theoretical joint model when this type of liner is present in the real joint to be simulated.

  • 70. Englund, Thomas
    et al.
    Wall, Johan
    Ahlin, Kjell
    Broman, Göran
    Significance of non-linearity and component-internal vibrations in an exhaust system2002Conference paper (Refereed)
    Abstract [en]

    To facilitate overall lay-out optimisation inexpensive dynamics simulation of automobile exhaust systems is desired. Identification of possible non-linearity as well as finding simplified component models is then important. A flexible joint is used between the manifold and the catalyst to allow for the motion of the engine and to reduce the transmission of vibrations to the rest of the exhaust system. This joint is significantly non-linear due to internal friction, which makes some kind of non-linear analysis necessary for the complete exhaust system. To investigate the significance of non-linearity and internal vibrations of other components a theoretical and experimental modal analysis of the part of a typical exhaust system that is downstream the flexible joint is performed. It is shown that non-linearity in this part is negligible. It is also shown that shell vibrations of the catalyst and mufflers as well as ovalling of the pipes are negligible in the frequency interval of interest. The results implies, for further dynamics studies, that the complete system could be idealised into a linear sub-system that is excited via the non-linear flexible joint, that the pipes could be modelled with beam elements and that the other components within the linear sub-system could also be modelled in a simplified way. Such simplified component models are suggested. The agreement between theoretical and experimental results is very good, which indicates the validity of the simplified modelling.

  • 71.
    Enwall, Anders
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Sjögren, Robert
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Simulation of Vehicle Response to Throttle Tip-in and Tip-out1999Other (Other academic)
    Abstract [en]

    A theoretical model for optimization of the dynamical behavior of a vehicle drive train was suggested and equations of motions derived. A Simulink model was developed to solve the resulting system of equations. Experimental verification showed good agreement with theory.

  • 72. Eres, Murat Hakki
    et al.
    Bertoni, Marco
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Kossman, Mario
    Scanlan, James
    Mapping customer needs to engineering characteristics: an aerospace perspective for conceptual design2014In: Journal of engineering design (Print), ISSN 0954-4828, E-ISSN 1466-1837, Vol. 25, no 1-3, p. 64-87Article in journal (Refereed)
    Abstract [en]

    Designing complex engineering systems, such as an aircraft or an aero-engine, is immensely challenging. Formal systems engineering practices are widely used in the aerospace industry throughout the overall design process to minimise the overall design effort, corrective re-work, and ultimately overall development and manufacturing costs. Incorporating the needs and requirements from customers and other stakeholders into the conceptual and early design process is vital for the success and viability of any development programme. This paper presents a formal methodology, the value-driven design (VDD) methodology that has been developed for collaborative and iterative use in the extended enterprise (EE) within the aerospace industry, and that has been applied using the concept design analysis (CODA) method to map captured customer needs into engineering characteristics and to model an overall ‘design merit’ metric to be used in design assessments, sensitivity analyses, and engineering design optimisation studies. Two different case studies with increasing complexity are presented to elucidate the application areas of the CODA method in the context of the VDD methodology for the EE within the aerospace sector.

  • 73. Ericson, Åsa
    et al.
    Johansson, Christian
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Nergård, Henrik
    Manufacturing knowledge: Going from production of things to designing value in use2015In: International Journal of Intelligent Decision Technologies, ISSN 1872-4981, E-ISSN 1875-8843, Vol. 9, no 1, p. 79-89Article in journal (Refereed)
    Abstract [en]

    A new vision in manufacturing is to develop product-service integrated value solutions. Today, few firms have fully realized this vision because they are not able to support the reasoning in the early stages of design. The purpose of this paper is to discuss engineers' cognitive challenge when replacing the core product rationale with value logic. The paper problematizes engineering design by dividing knowledge into the categories technically constructed (explicit) and socially constructed (tacit). In doing so, this study contributes the assumed effects of a perspective shift that could guide the development of computational tools.

  • 74.
    Fransson, Pär
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Pettersson, Gert
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Fatigue Life Prediction using Forces in Welded Plates of Moderate Thickness2000Other (Other academic)
    Abstract [en]

    A new finite element based method for fatigue life prediction has been examined. The method uses nodal forces and moments along the weld toe to define a structural stress perpendicular to the weld. The method was found to be less mesh-sensitive than ordinarie post-processing.

  • 75. Fredin, Johan
    Modelling, Simulation and Optimisation of a Machine Tool2009Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    To be competitive in today’s global market it is of great importance that product development is done in an effective and efficient way. To enhance functionality, modern products are often so-called mechatronic systems. This puts even higher demands on the product development work due to the complexity of such products. Simulation and optimisation have been proven to be efficient tools to support the product development process. The aim of this thesis is to study how the properties of mechatronic products can be efficiently and systemically predicted, described, assessed and improved in product development. An industrial case study of a water jet cutting machine investigates how simulation models and optimisation strategies can be efficiently developed and used to enhance functionality, flexibility and performance of mechatronic products. The knowledge gained from the case study is shown to be useful for companies developing machine tools. Most likely it is also useful for developers of other mechatronic products. The thesis shows that with the presented optimisation strategies, comprising a mix of different computerised optimisation algorithms and more classical engineering work, design problems with a large amount of design variables can be solved efficiently. A specific result is a validated simulation model for simulation and optimisation of a water jet cutting machine. As all mechatronic disciplines of the machine tool are considered simultaneously, synergetic effects can be utilised. Optimisation studies show a significant potential for improving manufacturing accuracy, for manufacturing speed and for a more light-weight design. Carrying out simulation and optimisation has also provided a great amount of information about the studied system, potentially useful in coming product development work. By reducing the number of physical prototypes through simulation and optimisation, the resource consumption during product development is reduced. Also, with more optimised products the resource consumption can be significantly reduced throughout the whole use phase. These benefits support the competitiveness of the product developing company as well as a sustainable development of society as a whole.

  • 76.
    Fredin, Johan
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Jönsson, Anders
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Broman, Göran
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Holistic methodology using computer simulation for optimisation of machine tools2012In: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 63, no 1, p. 294-301Article in journal (Refereed)
    Abstract [en]

    Virtual machine concepts supporting optimisation of machine tools have been developed in earlier work. The virtual machine concept is a tool that can describe the behaviour of a machine tool while considering the interaction between mechanics of the machines and the control system. Considerable amount of work has been done proving the concept and showing the potential of such a design tool in different contexts. Several studies have shown the potential of using the virtual machine concept, although, no work has been found that is exploring the potential of a full optimisation study. The aim of this work is to show the potential of the virtual machine concept in an optimisation study of the complete machine tool, including the mechanical system, parameters in the control system, the NC-code as well as choice of servo and drive systems. An efficient optimisation strategy is presented, making it possible to solve the complex optimisation problem within a reasonable amount of time. A combination of optimisation algorithms is used to achieve a fast and accurate way of solving the complex task to optimise the complete machine tool. Genetic algorithms, gradient based algorithms and more traditional hands on engineering are used for solving the optimisation problem. Post processing and data mining is suggested as a way of extracting as much information as possible from optimisation results with the aim to increase the knowledge about the studied system. An important conclusion is that the virtual machine should support the decision making in product development, not replace the product developers as regards decision making.

  • 77. Gazizov, Rafail
    et al.
    Ibragimov, Nail
    Blekinge Institute of Technology, School of Engineering, Department of Mathematics and Natural Sciences.
    Rudenko, Oleg
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Effect of resonant absorption in viscous and dry vibrating contact: Mathematical models and theory connected with slow dynamics and friction welding2014In: Communications in nonlinear science & numerical simulation, ISSN 1007-5704, E-ISSN 1878-7274, Vol. 19, no 2, p. 337-344Article in journal (Refereed)
    Abstract [en]

    Process of heating of thin layer located between two vibrating surfaces is studied. Energy loss goes on due to viscous or dry friction. Optimal quantities of shear viscosity and friction corresponding to maximum energy loss are determined. Resonant behavior of loss must be taken into account in the description of "slow dynamics" of rocks and materials exposed to high-intensity seismic or acoustic irradiation as well as in various technologies. Bonding of materials by linear friction welding, widely used in propulsion engineering, can exemplify such a technology.

  • 78. Gusev, V.A.
    et al.
    Rudenko, Oleg
    The Field of Radiative Forces and the Acoustic Streaming in a Liquid Layer on a Solid Half-Space2010In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 56, no 6, p. 861-870Article in journal (Refereed)
    Abstract [en]

    The acoustic field and the field of radiative forces that are formed in a liquid layer on a solid substrate are calculated for the case of wave propagation along the interface. The calculations take into account the effects produced by surface tension, viscous stresses at the boundary, and attenuation in the liquid volume on the field characteristics. The dispersion equations and the velocities of wave propagation are determined. The radiative forces acting on a liquid volume element in a standing wave are calculated. The structure of streaming is studied. The effect of streaming on small size particles is considered, and the possibilities of ordered structure formation from them are discussed.

  • 79. Gustavsson, Ingvar
    A Remote Access Laboratory for Electrical Circuit Experiments2003In: International journal of engineering education, ISSN 0949-149X, Vol. 19, no 3, p. 409-419Article in journal (Refereed)
    Abstract [en]

    Many laboratory experiments in electrical engineering courses can be performed remotely using real equipment in a laboratory. Traditional circuit theory experiments have been conducted over the Internet at Blekinge Institute of Technology (BTH) in Sweden using the same experimental set-up from different locations simultaneously. The circuits are formed using remotely controlled switch matrices. The instruments and switch matrices used are computer-based PXI (PCI Extensions for instrumentation) devices which have virtual front panels that can be displayed on a remote PC. This approach is neither a simulation nor a SCADA (Supervisory Control and Data Acquisition) application. The students control the instruments in the same way as they would in a local laboratory. The only difference is that they do not form the circuits and connect the test probes manually. These laboratory experiments have been used successfully in undergraduate engineering education at BTH and at Luleå University of Technology, Sweden using a lab server at BTH. Two transducer laboratory exercises are also available for more experienced students, who mostly welcome the chance of doing the experiments from home at any convenient time. These exercises contain comparatively slow mechanical movements allowing only one user to be logged on and controlling the experiments at once. Video transmission is provided so other users can follow what is happening and also perform parts of the experiments.

  • 80. Haller, Kristian
    Acoustical Measurements of Material Nonlinearity and Nonequilibrium Recovery2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A damaged material or a material with non perfect atomic geometry, dislocations or cracks, exhibits two types of characteristic responses to acoustic excitations. First is the fast nonlinear dynamics response that is present as long as the material is excited. As soon as the excitation stops the response disappear. Second is the Slow Dynamics, which detects alterations of the material properties. The properties are affected by, for example, a mechanical pulse, changes in temperature, pressure or humidity. When the cause of alteration stops the material is recovering towards its equilibrium state. This recovering can exist over a long period of time, much longer than the vibration from a mechanical pulse. The techniques used here, both the fast and Slow Dynamics, have been used for NonDestructive Testing to detect damage in objects. All of them are suitable for this purpose, but for different material and geometry different techniques can be advantageous. They offer the possibility to use relatively low frequencies which is advantageous because attenuation and diffraction effects are smaller for low frequencies. Therefore large and multi-layered complete objects can be investigated. Sometimes the position of the damage is required, but it is in general difficult to limit the geometrical extent of low-frequency acoustic waves. A technique is presented that constrains the wave field to a localized trapped mode so that damage can be located. The existence of trapped modes is shown using an open resonator concept and the localization is shown to be successful. The problem with intermittent and changing amplitudes, even when very small, is that the material is really never at equilibrium, or even at steady state. The measurement signal influences the outcome. The material is affected by its strain history and its constantly changing state, the fast and Slow Dynamics are hard to separate. A measurement technique keeping the internal strain constant has been used to minimize the influence of Slow Dynamics allowing observations of only nonlinearity. The influence of temperature is also studied with this technique.

  • 81. Haller, Kristian
    Nonlinear Acoustics Applied to NonDestructive Testing2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Sensitive nonlinear acoustic methods are suitable for material characterization. This thesis describes three nonlinear acoustic methods that are proven useful for detection of defects like cracks and delaminations in solids. They offer the possibility to use relatively low frequencies which is advantageous because attenuation and diffraction effects are smaller for low frequencies. Therefore large and multi-layered complete objects can be investigated in about one second. Sometimes the position of the damage is required. But it is in general difficult to limit the geometrical extent of low-frequency acoustic waves. A technique is presented that constrains the wave field to a localized trapped mode so that damage can be located.

  • 82. Haller, Kristian
    et al.
    Hedberg, Claes
    Advantages of Nonlinear Wave Modulation Spectroscopy (NWMS) compared to some linear acoustic techniques2003Conference paper (Refereed)
    Abstract [en]

    This paper describes test results of a nonlinear wave modulation spectroscopy (NWMS) technique. These techniques are based on the strong connection between nonlinearity and presence of micro or macro-cracks. NWMS includes existence of higher harmonics, the presence of sidebands and ratio between excitation frequency and sideband components. Tests of different nonlinear techniques have been performed and compared to linear techniques. Tensile beams have been used as specimens. Piezoceramics were applied and a high frequency signal transmitted into the specimen simultaneously as a low frequency. Sideband around the high frequency and higher harmonics were then studied to detect nonlinearities. If there are cracks present, the NWMS show nonlinearities by combining the different frequencies shown as sidebands from the high frequency component, and the higher harmonics' amplitudes will increase. NWMS techniques are more sensitive than linear as they can detect smaller cracks. NWMS is faster to evaluate than a linear scanning method, as it can interrogate a complete object in just one measurement, and NWMS is not as limited by complicated geometry of the specimen.

  • 83. Haller, Kristian
    et al.
    Hedberg, Claes
    Constant Strain Frequency Sweep Measurements on Granite Rock2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 100, no 6Article in journal (Refereed)
    Abstract [en]

    Like many materials, granite exhibits both nonlinear acoustic distortion and slow nonequilibrium dynamics. Measurements to date have shown a response from both phenomena simultaneously, thus crosscontaminating the results. In this Letter, constant strain frequency sweep measurements eliminate the slow dynamics and, for the first time, permit evaluation of nonlinearity by itself characterized by lower resonance frequencies and a steeper slope. Measurements such as these are necessary for the fundamental understanding of material dynamics, and for the creation and validation of descriptive models.

  • 84. Haller, Kristian
    et al.
    Hedberg, Claes
    Frequency sweep rate and amplitude influence on nonlinear acoustic measurements2006Conference paper (Refereed)
    Abstract [en]

    When subjecting a solid material to acoustic excitation with varying amplitude and sweep rate, the frequency shift response is not always behaving linear with amplitude. This phenomenon is connected to intricate nonlinear mechanics appearing in naturally imperfect materials and in damaged non-atomic solids. It is being investigated for different excitation amplitudes and for varying frequency sweep rates. This onset distribution can be mapped as an activation density.

  • 85. Haller, Kristian
    et al.
    Hedberg, Claes
    Nonlinear Ultrasonic Damage Response to Excitation Strength and Position2006Conference paper (Other academic)
    Abstract [en]

    A laminated carbon-fibre reinforced divinylcell plate is tested by a nonlinear ultrasonic technique for damage positioning. A high-frequency air-coupled transducer plate is placed above the plate surface, and a low-frequency contact source is fixed at one end. The high-frequency wave field fulfills the open resonator criteria making it localized inside the plate. The nonlinear damage response position is obtained by moving the high-frequency source on either side, having fixed sensors on both plate sides. Further, the nonlinear damage response is measured to change approximately linear with increase in high-frequency, or low-frequency, amplitude.

  • 86. Haller, Kristian
    et al.
    Hedberg, Claes
    Sound Velocity Dependence on Strain for Damaged Steel2008Conference paper (Refereed)
    Abstract [en]

    When making acoustic measurements on materials with cracks, there exist two types of behavior that influence the sound velocity monitored through the resonance frequency of the object. One is the material's nonlinearity, and the other is a slow recovery process of the material parameters towards equilibrium called Slow Dynamics. The former is a wave distortion taking place in the presence of the wave while the latter is a slow recovery process that makes the time history of the material state count. For the understanding of the dynamics of these solids it is necessary to be able to separate the effects of nonlinearity and slow dynamics. In this work, this has been accomplished by making measurements on steel at steady-state through keeping the strain constant. Normal frequency sweeps at different strains are compared to constant strain sweeps. As every material state parameter can induce a slow dynamic response it is important to keep control of humidity and temperature. Measurements performed at different temperatures give different results. An example of this is the presented resonance frequency plots for the temperatures 20, 25 and 30 degrees Celcius. © 2008 American Institute of Physics.

  • 87. Haller, Kristian
    et al.
    Hedberg, Claes
    Three Nonlinear NDE Techniques On Three Diverse Objects2005Conference paper (Refereed)
    Abstract [en]

    Non-Destructive Evaluation has been carried out on three different test objects, with three different methods based on exhibits of slow dynamics and nonlinear effects. The three diverse objects were cast iron, ceramic semi-conductors on circuit boards, and rubber. The three approaches were Higher Harmonics detection (HH), Nonlinear Wave Modulation Spectroscopy (NWMS), and Slow Dynamics (SD). For all of the objects the three approaches were tried. The results showed that for each of the objects, a different method worked the best. The cast iron worked best with nonlinear wave modulation, the ceramic semi-conductors worked well with the higher harmonics detection, while the rubber showed best results with slow dynamics.

  • 88. Haller, Kristian
    et al.
    Hedberg, Claes
    Rudenko, Oleg
    Slow variations of mechanical and electrical properties of dielectrics and nonlinear phenomena at ultrasonic irradiation2010In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 56, no 5, p. 660-664Article in journal (Refereed)
    Abstract [en]

    The interconnection between variations of elasticity and dielectric permittivity of mesoscopic solid systems under exposure to ultrasound is experimentally observed. A phenomenological theory generalizing Debye’s approach for polar fluids is developed to explain the measured data. The substitution of acoustic measurements by dielectric ones not only simplifies the procedure, but offers new possibilities to remotely evaluate the mechanical properties of materials and natural media.

  • 89.
    Haller, Kristian
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Olsson, Ulrika
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Method for Dynamic Automated Laser Measurement applied on Lightweight Test Panels1999Other (Other academic)
    Abstract [en]

    This thesis describes an automated approach to modal testing utilizing a robot control to position a laser vibrometer beam. The method developed reduces the time-consuming data acquisition considerable. A double curved aluminium panel was chosen as test specimen. The selected specimen is suitable because it is hard to measure the dynamic properties of these kind of lightweight structures with accelerometers. Results from the experimental modal analysis were compared to the results given from the FEM calculations. An excellent agreement between the two models was found.

  • 90. Haller, Kristian
    et al.
    Olsson, Ulrika
    Östholm, Stefan
    Method for Dynamic Automated Laser Measurement Applied on Lightweight Test Panels1999Conference paper (Refereed)
    Abstract [en]

    This paper describes an automated approach to modal testing utilizing a robot control to position a Laser Doppler Vibrometer (LVD) [1]. A programmed robotic system was used for the laser positioning. This kept the measurement set correctly identified with respect to the specimen geometry. The communication between the measurement program and the robot, the identification of the candidate robot system, and the mechanical design of the robot-vibrometer interface is described. For verification a sample measurement was performed and results are briefly presented.

  • 91.
    Hallstedt, Sophie
    Blekinge Institute of Technology, School of Engineering, Department of Strategic Sustainable Development.
    A Foundation for Sustainable Product Development2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Product development is a particularly critical intervention point for the transformation of society towards sustainability. Current socio-ecological impacts over product life-cycles are evidence that current practices are insufficient. The aim of this thesis is to form a foundation for sustainable product development through the integration of a sustainability perspective into product development procedures and processes. Literature reviews and theoretical considerations as well as interviews, questionnaires, observations, testing and action research through case studies in various companies have indicated gaps in current methodology and have guided the development of a new general Method for Sustainable Product Development (MSPD). This method combines a framework for strategic sustainable development based on backcasting from basic sustainability principles with a standard concurrent engineering development model. A modular system of guiding questions, derived by considering the sustainability principles and the product life-cycle, is the key feature. Initial testing indicates that this MSPD works well for identification of sustainability problems as well as for generation of possible solutions. However, these tests also indicate that there is sometimes a desire for a quick overview of the sustainability performance of a specific product category. This is to guide early strategic decisions before the more comprehensive and detailed work with the MSPD is undertaken, or, alternatively, when an overview is sufficient to make decisions. In response, a Template for Sustainable Product Development (TSPD) approach is presented as a supplement to the MSPD. To generate products that support sustainable development of society it is necessary to combine sustainability assessments with improvements of technical product properties. An introductory procedure for such sustainability-driven design optimization is suggested based on a case study. For maximum efficiency of a company in finding viable pathways towards sustainability, it is also necessary to coordinate different methods and tools that are useful for sustainable product development and integrate them into the overall decision-making processes at different levels in companies. To find gaps in the sustainability integration in a company’s decision system, an assessment approach is suggested based on case studies. A general conclusion from this research is that the support needed for making sustainability-related decisions are not systematically integrated in companies today. However, this thesis also indicates that it is possible to create generic methods and tools that aid the integration of sustainability aspects in companies’ strategic decision-making and product development. These methods and tools can be used to guide the prioritization of investments and technical optimization on the increasingly sustainability-driven market, thus providing a foundation for competitive sustainable product development.

  • 92.
    Hallstedt, Sophie
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Strategic Sustainable Development.
    Isaksson, Ola
    Clarification of sustainability consequences of manufacturing processes in conceptual design2013Conference paper (Refereed)
    Abstract [en]

    In the conceptual design of aircraft jet engine components, not only the product architecture and dimensions are set but the associate manufacturing processes are also defined. From a design decision point of view it is critical to identify and characterize the consequences of alternative solutions. This paper reports on a case, where a milling process needed to be selected in an early design phase of a jet engine component. An Electro-Chemical Milling process was considered but its impact on sustainability needed clarification. An approach that combined a simplified Environmental Impact Assessment with a Strategic Sustainability Assessment was used. The main finding and contribution from the work is a method that helps to clarify consequences of sustainability-related issues by combining the two analysis tools with a risk analysis implementation. The results reveal that once the consequences can be clarified, increased attention and understanding are gained.

  • 93. Hallstedt, Sophie
    et al.
    Ny, Henrik
    Robèrt, Karl-Henrik
    Broman, Göran
    An approach to assessing sustainability integration in strategic decision systems for product development2010In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 18, no 8, p. 703-712Article in journal (Refereed)
    Abstract [en]

    This article aims to explore a new approach to assess company decision systems regarding sustainability-related communication and decision support between senior management and product development levels. The assessment approach was developed in theory and its applicability was directly tested in action research in two small and medium-sized companies and two large companies. The results were validated against experiences made by two management consultancies. Our study indicates that successful companies should: (i) integrate sustainability into business goals and plans, backed up by suitable (ii) internal incentives and disincentives and (iii) decision support tools. Our study also indicates that the new assessment approach can be used as a template to assess the current state of sustainability integration in company decision systems.

  • 94. Hallstedt, Sophie
    et al.
    Thompson, Anthony
    Integrating Sustainability and Innovation Through a Master's Program in Product-Service Systems2010Conference paper (Refereed)
    Abstract [en]

    The results of unsustainable product innovation are evident worldwide. Products and their usage contribute to global sustainability problems. Companies building competence in innovation for sustainability will therefore gain competitive advantages in the evolving sustainability-driven market at the same time as sustainability is a driving force for innovation. Blekinge Institute of Technology (BTH) has a research group that brings together competences with the unifying purpose of supporting industrial capacity for sustainable product-service system innovation. From this research, it is evident that there is a need for systems innovators who can help create leap frog solutions as well as make sure that incremental improvements fit into a viable strategy towards a sustainable society. Industry needs people who can manage the whole innovation process for sustainability, including need-finding, design, implementation through to remanufacturing. BTH is therefore offering a comprehensive master’s program to prepare people to be systems' innovators for sustainability. This programme is focused where sustainability, innovation and product-service systems (PSS) meet. Supporting areas such as leadership, management and entrepreneurship are also included. The two-year program will allow students to engage in front-edge research results and will be continuously developed in close collaboration with industry to develop a relevant profile for graduates. Students will be engaged in ongoing research projects and have industrial projects. Upon completion, students will have practical experience in using methods and tools that support sustainable product innovation, as well as have a thorough theoretical understanding as a basis for development of new supplementary methods and tools as necessary.

  • 95. Hallstedt, Sophie
    et al.
    Thompson, Anthony
    Sustainability driven product development -some challenges and opportunities for aero industry2011Conference paper (Refereed)
    Abstract [en]

    Products contribute to global sustainability problems throughout their entire life cycles. The majority of opportunities to influence the sustainability performance of products come when the product is designed – far before it is created or put into use. Within the aeronautics industry, there are specific targets set out by the Advisory Council for Aeronautics Research in Europe (ACARE) with one of the high-level targets being an “ultra green air transport system.” At Volvo Aero, a leading manufacturer of aero engine components, this has turned into concrete design targets like light weight, noise/emission reduction and high reliability. Volvo Aero has been used as a case in this research survey to identify some challenges and opportunities of implementing a sustainability perspective in the product innovation process in the aero industry. The overall purpose of this paper is, then, to discuss these challenges and the associated opportunities to include such a sustainability perspective to reach a sustainability-driven product innovation process.

  • 96.
    Hallstedt, Sophie
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Strategic Sustainable Development.
    Thompson, Anthony
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Isaksson, Ola
    Larsson, Tobias
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Ny, Henrik
    Blekinge Institute of Technology, School of Engineering, Department of Strategic Sustainable Development.
    A Decision Support Approach for Modeling Sustainability Consequences in an Aerospace Value Chain2014In: PROCEEDINGS OF THE ASME INTERNATIONAL DESIGN ENGINEERING TECHNICAL CONFERENCES AND COMPUTERS AND INFORMATION IN ENGINEERING CONFERENCE, 2013, VOL 4, ASME Press, 2014, Vol. 3Conference paper (Refereed)
    Abstract [en]

    Next generation jet engine technologies are typically driven by performance, value and environmental challenges, and appropriate technologies are developed in international research programs. One on-going engine component technology project at an aerospace component manufacturer aims to develop an engine with less fuel consumption. A likely consequence is higher pressure in the core engine, which leads to higher temperature. One way to handle the higher temperature is using a more advanced Ti-alloy for the product component, which will render a different sustainability profile. One weakness in current decision situations is the inability to clarify and understand the “value” and “sustainability” implications compared to e.g. performance features of concepts. Both “value” and “sustainability” include a rich set of features important for successful introduction of new products and product-service solutions to the market. The purpose with this research is to provide decision support for companies in early development phases for assessment of value and sustainability consequences over product-service system lifecycles. A workshop was held with the aerospace component manufacturer and a value chain partner focusing on material handling, to: i) get a better understanding of activities, flows and ownership related to the studied materials at the two companies, ii) to understand the companies’ perspective at new suggested scenarios with regard to these materials, and iii) define relevant scenarios to look into more in depth from asustainability and value perspective. Three different scenarios were developed with differences in ownership, responsibilities and value streams. It is therefore essential to be able to quickly assess and optimize consequences of such alternative scenarios. Based on the workshop experiences and scenarios, a modeling and simulation approach to assess sustainability and value consequences for the scenarios is proposed. The sustainability consequences are based on a sustainability life cycle assessment and a risk assessment. Key features of the proposed tool include: consideration of the time dimension, societal sustainability consequences, risk assessment, company value assessment, and cost/revenue perspectives.

  • 97.
    Hallstedt, Sophie
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Strategic Sustainable Development.
    Thompson, Anthony
    Blekinge Institute of Technology, School of Engineering, Department of Strategic Sustainable Development.
    Lindahl, Pia
    Blekinge Institute of Technology, School of Engineering, Department of Strategic Sustainable Development.
    Key elements for implementing a strategic sustainability perspective in the product innovation process2013In: Journal of Cleaner Production, ISSN 0959-6526, Vol. 51, p. 277-288Article in journal (Refereed)
    Abstract [en]

    This article aims to present identified key elements for successful implementation of a strategic sus- tainability perspective in the early phases of the product innovation process. In-depth interview studies were conducted in six companies within the same corporate group. These, together with a review of literature, previous research and company documents, were a foundation for evaluating if and how a strategic sustainability perspective has been successfully implemented on a day-to-day basis in the product innovation processes of the studied companies. The results are divided into strengths and challenges of the companies with regard to implementing a strategic sustainability perspective in the product innovation process. From this research, eight key elements for successful implementation of a strategic sustainability perspective have been identified. These elements are divided into four categories: organization, internal processes, roles, and tools. It is posited that incorporating these key elements into product innovation processes will encourage a company to have a strategic sustainability perspective, which will support the company’s long-term success.

  • 98. Hedberg, Claes
    A multi-frequency solution for the Burgers equation1999Conference paper (Refereed)
    Abstract [en]

    A generalization of the single frequency Cole-Mendousse solution for the Burgers equation is shown. The solution is in the same form - a ratio between two Fourier series containing Bessel functions. The input is given as an arbitrary number of frequency components which can have any amplitude, frequency and phase. The solution is valid for any distance.

  • 99. Hedberg, Claes
    Basics of Nonlinear Time Reversal Acoustics2009Conference paper (Refereed)
    Abstract [en]

    An investigation of time reversal of nonlinear and non-dissipative or dissipative plane sound waves was made. Propagation and back propagation is time reversal invariant only when the dissipation is zero and the wave has not been shocked. A wave that has shocked has irretrievably lost part of its content. Still, if the wave and its derivatives are considered continuous there remain in theory forever information about the original signal. Factors like numerical accuracy and noise naturally set limits in practical situations.

  • 100. Hedberg, Claes
    Dynamic modelling of some nonlinear materials2002Conference paper (Refereed)
    Abstract [en]

    A nonlinear layer can be a model for a cloud of gas bubbles in a liquid, a crack or split plane in a solid, or contact between two tighted surfaces. Solutions were derived for media under strong load. Numerical calculations based on Preisach-Mayergoyz space description (nonlinear stress-strain relationships typical for solids containing mesoscopic inhomogeneities or defects) have given results like those obtained from LISA (see results by Delsanto). IMVITED. Non-uniform massdistribution of grains immersed into a vibrating fluid create internal forces which is responsible for generation of higher harmonics. Tests on slow dynamics were performed.

1234567 51 - 100 of 318
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf