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  • 1. Adolfsson, Vilhelm
    et al.
    Goldberg, Max
    Jawerth, Björna
    Lennerstad, Håkan
    Localized Galerkin Estimates for Boundary Integral Equations on Lipschitz Domanis1992In: SIAM Journal on Mathematical Analysis, Vol. 5, no 23, p. 751-764Article in journal (Refereed)
    Abstract [en]

    The Galerkin method is studied for solving the boundary integral equations associated with the Laplace operator on nonsmooth domains. Convergence is established with a condition on the meshsize, which involves the local curvature on certain approximating domains. Error estimates are also proved, and the results are generalized to systems of equations.

  • 2. Ahlin, Kjell
    Comparison of Test Specifications and Measured Field Data2006In: Sound and Vibration, ISSN 0022-460X , Vol. 40, no 9, p. 22-25Article in journal (Refereed)
    Abstract [en]

    It is not always obvious how to compare a given test specification with measured field data. This article presents a systematic method based on the shock response spectrum and the fatigue damage spectrum. A random-on-random test specification for tracked vehicles, AECTP 400, is used as an example.

  • 3. Ahlin, Kjell
    et al.
    Granlund, Johan
    Lindström, Fredric
    Comparing Road Profiles with Vehicle Perceived Roughness2004In: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 36, no 2-3, p. 270-286Article in journal (Refereed)
    Abstract [en]

    Accurate road profiles are useful in vehicle design, such as for simulation of durability and ride quality. Laser/inertial profilometers typically record I mm wide profiles. The question is how well such a profile matches perceived vehicle wheel roughness. The objective here was to create a more representative wheel track longitudinal profile. Simulated and measured wheel vibration was compared on a 6km long road. Simulations were made for several definitions of the profile. Results for single laser sensor profiles showed reasonable likeness to truck perceived roughness. By far the best likeness (14.5% better) was achieved when the profile was based on triangular 25%-50%-25% weighted data from three sensors in the wheel track. Clearly, vehicle engineers can benefit from using multiple laser profile sensors, instead of a single sensor. This will improve test accuracy, thus reducing vehicle design project lead times and costs.

  • 4. Ahlin, Kjell
    et al.
    Magnevall, Martin
    Josefsson, Andreas
    Simulation of forced response in linear and nonlinear mechanical systems using digital filters2006Conference paper (Refereed)
    Abstract [en]

    There exist many methods to calculate forced response in mechanical systems. Some methods are slow and the errors introduced are unknown. The paper presents a method that uses digital filters and modal superposition. It is shown how aliasing can be avoided as well as phase errors. The parameters describing the mechanical system are residues and poles, taken from FEA models, from lumped MCK systems, from analytic solutions or from experimental modal analysis. Modal damping may be used. The error in the calculation is derived and is shown to be only a function of the sampling frequency used. When the method is applied to linear mechanical systems in MATLAB it is very fast. The method is extended to incorporate nonlinear components. The nonlinear components could be simple, like hardening or stiffening springs, but may also contain memory, like dampers with hysteresis. The simulations are used to generate test data for development and evaluation of methods for identification of non-linear systems.

  • 5.
    Aisvaran, Chandramohan
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Study of non-linear strain path in sheet metal forming2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At present, Sheet Metal Forming (SMF) is not just limited to increasing demand from automobile industries but also to various other manufacturing industries that utilize sheet metal forming processes. The surplus demands for optimised manufacturing products warrant the need for an extended decisive study on SMF. 

    One such area of study in SMF is formability. Traditionally, formability is predicted using the conventional Forming Limit Curve (FLC). But when it comes to complex SMF processes, FLC failure model can sometimes overestimate (for low uniaxial straining) or underestimate (for bi-axial straining) failure. This thesis focuses on suitable test procedures to generate non-linear strain paths and prediction of formability using the concept of Generalized Forming Limit Curve (GFLC). Initially, through systematic literature review, two-step process is chosen as the test procedure in this thesis. The test procedure was simulated in LS-Dyna to obtain results which are then used by GFLC concept to predict formability for a bi-linear deformation history. The predicted formability using the concept of GFLC is then compared with the predicted formability using FE-simulation and using experimentation.  The found percent error for GFLC prediction compared to that of FE-simulation prediction is 11% and the percent error for GFLC prediction and experimentation prediction is 14%. However, these two predictions can not be used to validate the GFLC prediction. This is because in this thesis GFLC procedure uses data obtained from FE-simulation with GISSMO failure model. Through literature, it is identified that the GFLC concept can be applied for multi-linear deformation histories to predict formability and the method to do so is explained in detail in this thesis. Finally, it is concluded that the use of the GFLC concept in conjunction with the two-step drawing process to predict formability for bi-linear deformation history is acceptable.

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  • 6.
    Andersson, Carry
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Kisswani, Lennart
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Dynamic Characteristics of a Tool Holder Shank in Lathe2000Other (Other academic)
    Abstract [en]

    Dynamic characteristics of a Tool Holder Shank were determined by using the Finite Element Method and Experimental Modal Analysis. Good agreement between FE-model and the experimental model was obtained for the Tool Holder Shank itself. With the Tool Holder Shank in Lathe the agreement was less good. Reasons for this are discussed. Suggestions for further work on including actuators to reduce vibrations are given.

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  • 7.
    Andraéy, Erik
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Development of verified FE simulation method on crimp joint with gasket: A combined experimental and numerical study2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When developing drivetrain cooling modules for commercial vehicles, the top priority is the strength of the products. The reason lays within the structural change that companies are undergoing where the warehouses are minimized and the companies are relying on the transportation of commercial vehicles. If a drivetrain cooling module would fail to maintain a targeted temperature range of the drivetrain, there is not long until the vehicle is forced to a stop. At worst, the downtime of commercial vehicles can cause companies to come to a halt as well. Therefore, developing verified FE simulation methods together with strength verification tests, are some of the core activities to ensure the strength of the cooling modules before implementation in vehicles.

    One of the methods that have not been sufficiently verified regards how to perform structural FEA on a crimp joint with a gasket. A crimp joint is established through a hemming process, where the aluminium header tabs are crimped over the polyamide tank, creating a watertight seal together with a gasket. The objective of this master’s thesis is to verify the existing simulation methods of the crimp joint and determine the margin of error with respect to strains. The objective of this thesis is also to develop a verified FE simulation method with a lower margin of error compared to the existing methods. The verification of the methods has been conducted through a comparison between numerical results and an experimental stress analysis, where the strain located on the header is measured with strain gauges in a pressure pulsation rig.

    The average margin of error found on the three existing methods of simulating the crimp joint was 39,7%, 13,4%, and 11,5% located on the outer bottom dimensioning radius of the crimp joint at a pressure of 100 kPa. However, the method used to determine the margin of error was found to be invalid, but the margin of error is only slightly affected by the verification method where the existing methods still are insufficiently representing the crimp joint. The method of determining the margin of error was then corrected for the development of the new method to represent the crimp joint in the FE model. The developed method in this thesis has an average margin of error of 6,9% at 100, 160, 220, and 260 kPa.

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  • 8.
    Andreasson, Eskil
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Realistic Package Opening Simulations: An Experimental Mechanics and Physics Based Approach2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    A finite element modeling strategy targeting package opening simulations is the final goal with this work. The developed simulation model will be used to proactively predict the opening compatibility early in the development process of a new opening device and/or a new packaging material. To be able to create such a model, the focus is to develop a combined and integrated physical/virtual test procedure for mechanical characterization and calibration of thin packaging materials. Furthermore, the governing mechanical properties of the materials involved in the opening performance needs to be identified and quantified with experiments. Different experimental techniques complemented with video recording equipment were refined and utilized during the course of work. An automatic or semi-automatic material model parameter identification process involving video capturing of the deformation process and inverse modeling is proposed for the different packaging material layers. Both an accurate continuum model and a damage material model, used in the simulation model, were translated and extracted from the experimental test results. The results presented show that it is possible to select constitutive material models in conjunction with continuum material damage models, adequately predicting the mechanical behavior of intended failure in thin laminated packaging materials. A thorough material mechanics understanding of individual material layers evolution of microstructure and the micro mechanisms involved in the deformation process is essential for appropriate selection of numerical material models. Finally, with a slight modification of already available techniques and functionalities in the commercial finite element software AbaqusTM it was possible to build the suitable simulation model. To build a realistic simulation model an accurate description of the geometrical features is important. Therefore, advancements within the experimental visualization techniques utilizing a combination of video recording, photoelasticity and Scanning Electron Microscopy (SEM) of the micro structure have enabled extraction of geometries and additional information from ordinary standard experimental tests. Finally, a comparison of the experimental opening and the virtual opening, showed a good correlation with the developed finite element modeling technique. The advantage with the developed modeling approach is that it is possible to modify the material composition of the laminate. Individual material layers can be altered and the mechanical properties, thickness or geometrical shape can be changed. Furthermore, the model is flexible and a new opening device i.e. geometry and load case can easily be adopted in the simulation model. Therefore, this type of simulation model is a useful tool and can be used for decision support early in the concept selection of development projects.

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  • 9.
    Andreasson, Eskil
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Håkansson, Paul
    Sandgren, Martin
    Jönsson, Joel
    Deformation and Damage Mechanisms in Thin Ductile Polymer Films2013Conference paper (Refereed)
    Abstract [en]

    The mechanical material behavior of highly extensible or ductile polymer films used in the packaging industry has been studied in this work. The polymer material, consisting of different variants of polyethylene grades, is used as several components in the packaging material structure at Tetra Pak®. Experimental tensile tests were used to quantify the mechanical behavior and to be able to calibrate numerical constitutive material models. The studied polymer materials were able to withstand large deformations before breaking, involving both necking in the width and thickness direction of the specimen. During deformation re-orientation of polymer chains and substantial strain-hardening were also occurring. The latter effect was accounted for in the presented material modeling approach. The numerical simulations were solved in the general finite element software Abaqus version 6.13. In this work a continuum damage modeling (CDM) approach was used. CDM which are attractive in macro scale applications, thus solving our engineering problems, was chosen in this study due to the computational efficiency. A damage model consisting of two functionalities; initiation of damage and evolution of damage was suitable for modeling the ductile fracture behavior. During the numerical analysis it has been assumed that the polymer materials are isotropic, homogenous through the thickness, independent of strain rate and independent of temperature to ease the material parameters identification.

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  • 10. Andreasson, Eskil
    et al.
    Jemal, Abdulfeta
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Katangoori, Rahul Reddy
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Is it possible to open beverage packages virtually? Physical tests in combination with virtual tests in Abaqus.2012Conference paper (Refereed)
    Abstract [en]

    The opening mechanism in a beverage package, where a mixed mode failure occurs, is a rather complex phenomenon. A better knowledge in respect of fracture mechanics is needed for the proactive prediction of the overall opening performance. Reliable material data used for virtual simulation of the opening mechanism is extracted by characterization and calibration of the packaging materials. Knowledge of how to choose appropriate constitutive models for the continuum material and how the damage initiates and propagates to various loading conditions is of great interest. The virtual tests, replicating the physical tests, are performed with the aid of the finite element method. Non-linear material response, anisotropic material behaviour, large deformation and fracture mechanics are identified effects that are all included in the virtual model. The results presented in this paper show possible selections of material models in conjunction with material damage models, adequately describing thin polymer films behaviour. Comparison between the physical test and the virtual test, exerted to fracture Mode I – Centre Cracked Tension, showed a good correlation for the chosen modeling technique.

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  • 11.
    Andreasson, Eskil
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Jönsson, Joel
    Tetra Pak, SWE.
    Advancements in package opening simulations2014In: Procedia Materials Science / [ed] Zhang, Z; Skallerud, B; Thaulow, C; Ostby, E; He, J, Elsevier, 2014, Vol. 3, p. 1441-1446Conference paper (Refereed)
    Abstract [en]

    The fracture mechanical phenomenon occurring during the opening of a beverage package is rather complex to simulate. Reliable and calibrated numerical material models describing thin layers of packaging materials are needed. Selection of appropriate constitutive models for the continuum material models and how to address the progressive damage modeling in various loading scenarios is also of great importance. The inverse modeling technique combined with video recording of the involved deformation mechanisms is utilized for identification of the material parameters. Large deformation, anisotropic non-linear material behavior, adhesion and fracture mechanics are all identified effects that are needed to be included in the virtual opening model. The results presented in this paper shows that it is possible to select material models in conjunction with continuum material damage models, adequately predicting the mechanical behavior of failure in thin laminated packaging materials. Already available techniques and functionalities in the commercial finite element software Abaqus are used. Furthermore, accurate descriptions of the included geometrical features are important. Advancements have therefore also been made within the experimental techniques utilizing a combination of microCT-scan, SEM and photoelasticity enabling extraction of geometries and additional information from ordinary experimental tests and broken specimens. Finally, comparison of the experimental opening and the virtual opening, showed a good correlation with the developed finite element modeling technique.

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  • 12.
    Andreasson, Eskil
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Kao-Walter, Sharon
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Ståhle, Per
    Micro-mechanisms of a laminated packaging material during fracture2014In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 127Article in journal (Refereed)
    Abstract [en]

    The micro-mechanisms of fracture in a laminate composed of an aluminium foil and a polymer film are considered in this study. The laminates as well as the individual layers, with and without premade centre-cracks, were tensile tested. Visual inspection of the broken cross-sections shows that failure occurs through localised plasticity. This leads to a decreasing and eventually vanishing cross-section ahead of the crack tip for both the laminate and their single constituent layers. Experimental results are examined and analysed using a slip-line theory to derive the work of failure. An accurate prediction was made for the aluminium foil and for the laminate but not for the freestanding polymer film. The reason seems to be that the polymer material switches to non-localised plastic deformation with significant strain-hardening.

  • 13.
    Andreasson, Eskil
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Mehmood, Nasir
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Kao-Walter, Sharon
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Trouser tear tests of two thin polymer films2013Conference paper (Refereed)
    Abstract [en]

    Trouser tear testing has been concerned in this research work. A polypropylene film and a low density polyethylene film used in the packaging industry are considered. The experimental trouser tear tests showed different results for both materials when they were subjected to load in different material directions. Therefore the hypothesis was verified, that the in-plane material orientation/alignment induced during manufacturing, hence creating anisotropic in-plane mechanical properties, also affects the tearing behavior. A brittle-like failure was shown in the polypropylene film while the low density polyethylene presented a highly ductile behavior. The two polymer films can be classified as one low-extensible and one high-extensible material according to the test method utilized. Material parameters in the principal material directions i.e. manufacturing direction and cross direction were extracted from the experimental tests for further numerical studies. Scanning electron microscope was used for micromechanical and fractographical analysis of the crack tip and crack surfaces created during the tests. The methods discussed will help classify different groups of materials and can be used as a predictive tool for the crack initiation and crack propagation path in packaging material, especially thin polymer films.

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  • 14.
    Andreasson, Eskil
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Mehmood, Nasir
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Mao, Tan
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    An Experimental, Numerical and SEM Study of Fracture in a Thin Polymer Film2014In: MATERIALS STRUCTURE & MICROMECHANICS OF FRACTURE VII, Trans Tech Publications Inc., 2014, Vol. 592-593, p. 225-+-Conference paper (Refereed)
    Abstract [en]

    Observations and analysis of samples from scanning electron microscopic (SEM) micrographs has been concerned in this work. The samples originate from fractured mechanical mode I tensile testing of a thin polymer film made of polypropylene used in the packaging industry. Three different shapes of the crack; elliptical, circular and flat, were used to investigate the decrease in load carrying capacity. The fracture surfaces looked similar in all studied cases. Brittle-like material fracture process was observed both by SEM micrographs and the experimental mechanical results. A finite element model was created in Abaqus as a complementary tool to increase the understanding of the mechanical behaviour of the material. The numerical material models were calibrated and the results from the simulations were comparable to the experimental results.

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  • 15.
    Andreasson, Eskil
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Mehmood, Nasir
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Mao, Tan
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Kao-Walter, Sharon
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Experimental and Numerical fracture of cracks emanating from different types of flaws in thin polymer films2013Conference paper (Refereed)
    Abstract [en]

    Fracture mechanical Mode I tensile testing has been performed on an oriented polyproplyne film used in packaging industry. Physical Tensile testing for the continuum material has been performed to observe the material strength and to extract continuum material properties for numerical analysis. Fracture mechanical testing of different shaped notches is performed to observe the failure initiation in the material. A brittle-like failure was shown in the polypropylene film while the low density polyethylene presented a highly ductile behavior. A finite element method (FEM) strategy has been successfully developed to perform numerical analysis of polymer films. The developed FEM model gives an accurate and approximate method to compare and analyze the experimental and numerical results. The obtained results have shown a very fine similarity under theoretical, experimental and numerical analysis. Depending on crack geometry different shape crack effects showed the transferability of localized stresses at different points around the crack. Fracture surface and fracture process is analyzed using scanning electron microscope (SEM). Brittle failure with small deformation and presence of small voids and their coalescence has also been shown in SEM micrographs for LDPE material. The methods discussed will help classify different groups of materials and can be used as a predictive tool for the crack initiation and crack propagation path in packaging material, especially thin polymer films.

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  • 16.
    Andreasson, Eskil
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Persson, Leo
    Jacobsson, Henrik
    Nordgren, Johan
    Integrating Moldflow and Abaqus in the Package Simulation Workflow2013Conference paper (Refereed)
    Abstract [en]

    Tetra Pak has used numerical simulation tools for plastic injection molding (Moldflow) and structural analysis (Abaqus/Implicit and Abaqus/Explicit) for many years. Today these two simulation tools are used independently of each other without any coupling. How these two disciplines can be combined to better predict the mechanical response of a polymer component is presented in this work. The manufacturing process, in this case injection molding, creates the mechanical properties of the produced polymer part. Process settings, material selection and molding tool geometry affect the polymer flow, material orientation and rate of crystallinity. A method to build a layered finite element model in Abaqus using results from Moldflow simulations regarding crystallinity growth and molecular orientation is proposed. Relatively simple material models were utilized and assigned for each individual material layer through the thickness in the polymer part. These constitutive models were derived phenomenologically from experimental test results and could adequately capture both the microscopic and the macroscopic behavior in a more realistic way. The numerical results showed a good agreement with the experimental results, both regarding visual appearance and force/displacement response.

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  • 17.
    Bandari, Shiva Ram
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Investigation on Flow Control Valve by CFD Simulation2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In a water distribution system, Flow Control Valve is used to control the flow rate in the pipeline connections. In this thesis, a fixed flow control valve is investigated to reduce the flow rate and set to deliver the pre-set flow of 5-6 LPM (litre per minute). Which helps to distribute the water for a maximum period and maintains the usage only for the drinking purpose. A geometry of FCV with a ball check valve is implemented, where the ball check helps to stop the back flow of the fluid from the valve. Detailed inspection of dynamic changes in pressure and flow velocity in the valve are conducted through simulation. The study of fluid properties describes the expected design and specifies the flow structure in the valve. The results of this project demonstrate a good performance of the design-build and influence the requirements. The obtained values in the simulation, analytical and experimental results are compatible, which concludes the survey of FCV is equipped to custom.

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  • 18.
    Barlo, Alexander
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Failure Prediction of Complex Load Cases in Sheet Metal Forming: Emphasis on Non-Linear Strain Paths, Stretch-Bending and Edge Effects2023Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    With the increased focus on reducing carbon emissions in today’s society, several industries have to overcome new challenges, where especially the automotive industry is under a lot of scrutiny to deliver improved and more environmentally friendly products. To meet the demands from customers and optimize vehicles aerodynamically, new cars often contain complex body geometries, together with advanced materials that are introduced to reduce the total vehicle weight. With the introduction of the complex body components and advanced materials,one area in the automotive industry that has to overcome these challenges is manufacturing engineering, and in particular the departments working with the sheet metal forming process. In this process complex body component geometries can lead to non-linear strain paths and stretch bending load cases, and newly introduced advanced materials can be prone to exhibit behaviour of edge cracks not observed in conventional sheet metals. This thesis takes it onset in the challenges seen in industry today with predicting failure of the three complex load cases: Non-Linear Strain Paths, Stretch-Bending,and Edge Cracks. Through Finite Element simulation attempts are made to accurately predict failure caused by aforementioned load cases in industrial components or experimental setups in an effort to develop post-processing methods that are applicable to all cases.

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  • 19.
    Barlo, Alexander
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Sigvant, Mats
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Kesti, V.
    SSAB Europe Oy, Finland..
    Islam, Md. Shafiqul
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Tuan Pham, Quoc
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Pilthammar, Johan
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Determination of Edge Fracture Limit Strain for AHSS in the ISO-16630 Hole Expansion Test2023In: 42ND CONFERENCE OF THE INTERNATIONAL DEEP DRAWING RESEARCH GROUP / [ed] Asnafi, N Lindgren, LE, IOP PUBLISHING LTD , 2023, Vol. 1284, article id 012027Conference paper (Refereed)
    Abstract [en]

    With the increased demand for application of sustainable materials and lightweight structures, the sheet metal forming industry is forced to push existing materials to the limits. One area where this is particular difficult is when it comes to assessing the formability limit for sheet edges. For decades, the ISO-16630 Hole Expansion Test (HET) has been the industry standard for expressing the edge formability of sheet metals through the Hole Expansion Ratio (HER). However, in recent years, this test has been criticized for its high scatter in results for repeated experiments. This scatter has been suspected to be caused by the operator-reliant post-processing of the test, or variations in the cutting conditions for the different test specimens. This study investigates the impact of shifting the evaluation point of the test from the through-thickness crack to the onset of surface failure on the reported scatter, as well as performs inverse modeling of the Hole Expansion Test to obtain an edge limit strain value.

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  • 20.
    Barlo, Alexander
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Sigvant, Mats
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Manopulo, Niko
    AutoForm Development GmbH, CHE.
    Islam, Md. Shafiqul
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Pilthammar, Johan
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Failure Prediction of Automotive Components Utilizing a Path Independent Forming Limit Criterion2022In: Key Engineering Materials / [ed] Vincze G., Barlat F., Trans Tech Publications Inc., 2022, p. 906-916Conference paper (Refereed)
    Abstract [en]

    An area in the automotive industry that receives a lot of attention today is the introduction of lighter and more advanced material grades in order to reduce carbon emissions, both during production and through reduced fuel consumption. As the complexity of the introduced materials and component geometries increases, so does the need for more complex failure prediction approaches. A proposed path-independent failure criterion, based on a transformation of the limit curve into an alternative evaluation space, is investigated. Initially, the yield criterion used for this transformation of the limit curve was investigated. Here it was determined that the criterion for the transformation could not be decoupled from the material model used for the simulation. Subsequently, the approach using the transformed limit curve was tested on an industrial case from Volvo Cars, but a successful failure prediction was not obtained. © 2022 The Author(s). Published by Trans Tech Publications Ltd, Switzerland.

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  • 21. Bathelt, Jens
    et al.
    Jönsson, Anders
    How to Implement the Virtual Machine Concept Using xPC Target2003Conference paper (Refereed)
    Abstract [en]

    This paper presents an overview of the historical background of the virtual machine, containing a real control, a machine simulation and a 3D machine visualisation. This setup enables realistic system simulations, since the simulation input comes from a real control. The first known implementation of the virtual machine using xPC Target is described with an existing water jet cutting machine as an example. MathWorks products offer all necessary software for the presented setup, except the interface for the actual speed value from the simulated incremental encoder to the control. The unique xPC driver implementation, as a noninlined C-MEX S-Function, is presented at the end of this paper. The successful implementation of the virtual machine demonstrates the feasibility of the presented approach.

  • 22. Bathelt, Jens
    et al.
    Jönsson, Anders
    Bacs, Christian
    Kunz, Andreas
    Meier, Markus
    Conceptual Design Approach For Mechatronic Systems Controlled by a Programmable Logic Controller (PLC)2003Conference paper (Refereed)
    Abstract [en]

    Traditionally, the development of mechatronic systems starts with the mechanical design. Later electronic components and program logic for the product are added. This work proposes an improved interdisciplinary concurrent product development process with an enhanced function structure for the conceptual design phase. The new methodology is based on the German guideline VDI 2221 [1]. Transition conditions, time aspects and logic flow are added to the normal function structure. An example shows how to use the improved function structure. The enhanced function structure is used to derive the initial logic for the development of the PLC program controlling the machine later on. Since the extended function structure also covers the traditional information, it can still be used when building the assembly tree. By adding more information in the neutral function structure, the same information can be used for the mechanical design as well as for the electronic and logical design. The interdisciplinary communication and documentation among the engineers will be improved and errors in the concept will be detected earlier.

  • 23. Bathelt, Jens
    et al.
    Jönsson, Anders
    Bacs, Christian
    Meier, Markus
    Modularisierung SPS-gesteuerter mechatronischer Systeme2003Conference paper (Refereed)
    Abstract [en]

    Rein mechanische Lösungen werden zunehmend von mechatronischen Systemen abgelöst. Der X-by-wire Ansatz zeigt auch, dass der Anteil an mechanischen Teillösungen eines mechatronischen Systems immer weiter zurückgeht. Der vorliegende Beitrag skizziert einen Entwicklungsprozess für SPS-gesteuerte mechatronische Systeme, der dem immer wichtiger werdenden Steuerungsanteil Rechnung trägt. Dabei steht das parallele Arbeiten der Steuerungstechnik und der Konstruktion im Vordergrund, um die Entwicklungszeiten zu verkürzen und Fehler früher zu erkennen. Realisiert wird dies durch eine fachspezifische Modularisierung, deren erste Modulhierarchie als Ausgangslage der jeweiligen Disziplinen fungiert und somit einen parallelen Start ermöglicht. In dieser Arbeit werden Regeln vorgestellt, um die fachspezifischen Module von einer Funktionsstruktur abzuleiten. Abschliessend wird das Vorgehen anhand eines Industriebeispieles erläutert.

  • 24.
    Bayat, Hamidreza
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Abbasi, Mohammad
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Investigation of the basic mechanics of edge cracking in sheet aluminum forming2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As technology is developing in all automotive companies, car body designers have also investigated new materials such as composite and aluminum alloys. Designing modern car structures has also created various challenges in the production process, including formability limitations. The main purpose of this research work was to develop a test setup for an open-hole uniaxial tensile test and investigate the effect of the cutting tool on the shearing edge quality of the series 6000 aluminum alloy and materials formability as a result. To approach this significant issue, detecting the onset of necking and forming limit curves FLC using 3D digital image correlations (DIC) capabilities were studied. Two methods based on strain rate for evaluating the instability through 3D DIC and Matlab were applied. Eighteen specimens in rolling, transverse, and diagonal directions were investigated. Although the results of the tensile test machine are close for all tests, due to 3D DIC limitations, detecting the onset of necking was hard to obtain. 

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    Investigation of the basic mechanics of edge cracking in sheet Aluminum forming
  • 25.
    Berglund, Pierre
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Pettersson, Johan
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Dynamic Characteristics of Exhaust System Hangers1999Other (Other academic)
    Abstract [en]

    Comfort in automobiles is greatly affected by vibrations and noise transmitted to the chassis from the engine. This is a study of the dynamic characteristics of exhaust system hangers, which is an important transfer path for vibrations. Theoretical and experimental modal analysis is used to suggest design parameters that increase the natural frequencies to above 450 Hz for two hanger types.

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    Dynamic Characteristics of Exhaust System Hangers
  • 26. Bertoni, Alessandro
    et al.
    Bertoni, Marco
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Isaksson, Ola
    Value visualization in Product Service Systems preliminary design2013In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 53, p. 103-117Article in journal (Refereed)
    Abstract [en]

    Emerging from a study in the European aerospace industry, this paper identifies a gap in the way value-related information is communicated to designers of hardware in the preliminary stages of Product Service System (PSS) design. To fit this gap a Lifecycle Value Representation Approach, named LiVReA, that uses color-coded 3D CAD models to enable value information to be translated into visual features, is presented. Such approach aims at enhancing designers' awareness of the value contribution of an early design concept on the overall PSS offer by complementing requirements-based information with criteria reflecting the fulfillment of customers and system value. The paper details the development of the approach, its underlying rationale, the results of preliminary validation activities and the potential for industrial application in the light of the currently available PSS representation tools

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  • 27.
    Bertoni, Alessandro
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Bertoni, Marco
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Johansson, Christian
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Analysing the effects of value drivers and knowledge maturity in preliminary design decision-making.2015In: ICED 15, VOL 10: DESIGN INFORMATION AND KNOWLEDGE MANAGEMENT, Design Society , 2015Conference paper (Refereed)
    Abstract [en]

    The paper presents the results of a three-days experiment to test the use of informationfrom a value assessment model and from a knowledge maturity scale in decisionmakingin preliminary design. A visual analogue scale was used to collect individualinformation from designers through questionnaires. Bivariate statistical analysis wasapplied to study the correlations between both the use of value drivers and knowledgematurity and the designers' awareness of the design problem to be addressed. Resultsshow that value drivers and knowledge maturity information increase the decisionmakers’ awareness of (1) the different perceptions of design team members about theneeds to be satisfied and (2) the technical solution to be developed in the productconcept under consideration.

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  • 28.
    Bertoni, Marco
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Bertoni, Alessandro
    Broeze, Henk
    Dubourg, Gilles
    Sundhurst, Clive
    Using 3D CAD models for value visualization: an approach with SIEMENS NX HD3D Visual Reporting2014In: Computer-Aided Design and Applications, ISSN 1686-4360, Vol. 11, no 3, p. 284-294Article in journal (Refereed)
    Abstract [en]

    Recent literature in Systems Engineering has suggested the use of “value” to drive decision-making activities during preliminary design, in particular when choosing technologies and components for a complex system. However, to correctly evaluate design trade-offs, a visual link has to be established between the results of the value model and a product shape/geometry. This paper proposes the use of color-coded 3D CAD models to support the visualization of value analysis results in a Stage-Gate® process. The approach has been developed and exemplified within a case study related to the design of an aero-engine component, and has been demonstrated using SIEMENS NX HD3D Visual Reporting. The results of verification activities conducted in a laboratory setting show that the use of color-coded 3D CAD models increases the decision makers’ awareness of value-related information in a Stage-Gate process.

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  • 29.
    Bertoni, Marco
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Bertoni, Alessandro
    Isaksson, Ola
    Amnell, Henrik
    Johansson, Christian
    Value-oriented concept selection in aero-engine sub-systems design: the EVOKE approach2013Conference paper (Refereed)
    Abstract [en]

    Value Driven Design methodologies extend the Requirements Management and Systems Engineering processes to reduce time and costs needed to identify the right solution direction to be pursued in detailed design. Emerging from the findings of an EU FP7 research project, the paper describes an approach, named EVOKE, that uses value as a basis for preliminary concept selection in the design of system components. EVOKE takes as input a list of value dimensions and drivers communicated by the system integrators, together with information about the high-level engineering characteristics of a candidate design, to enable early stage value analysis to be executed the by sub-system manufacturers. The approach and its technological enablers are described in detail through the use of a case study related to the design of new intermediate compressor case for turbofan engines.

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  • 30.
    Bertoni, Marco
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Bertoni, Alessandro
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Johansson, Christian
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Knowledge Enabled Engineering2015In: International Workshop of Advanced Manufacturing and Automation, Trans Tech Publications Inc., 2015Conference paper (Refereed)
    Abstract [en]

    The development of complex product-service combinations challenges the existing practices for engineering knowledge management. The objective of the paper is to highlight how such practices need to change to meet the engineers’ demand for knowledge when developing “functions” instead of merely hardware. It further proposes Knowledge Enabled Engineering (KEE) as an umbrella term that collects engineering knowledge management methods and tools inspired by the second wave of knowledge management, and that are aimed to meet needs of today’s modern knowledge workers in engineering organizations. The current state of readiness of these approaches is eventually described together with results from verification and validation activities.

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  • 31.
    Bertoni, Marco
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Eres, Hakki
    Scanlan, Jim
    Co-creation in complex supply chains: the benefits of a Value driven Design approach2014In: Product Development in the Socio-sphere: Game Changing Paradigms for 21st Century Breakthrough Product Development and Innovation / [ed] Schaefer, Dirk, Switzerland: Springer International Publishing , 2014Chapter in book (Refereed)
    Abstract [en]

    In the last decade, as the manufacturing companies have reconsidered the overall concept of goods production, their focus shifted from developing ‘products’ to ‘solutions’. In complex supply chains, the combination of products and services that maximize customers’ and stakeholders’ value can be identified only if manufacturers improve their ability to co-create, establishing more interactive relationships with end users, clients and sub-contractors. Methodologies for Value Driven Design (VDD) are emerging as enablers for cross-functional and cross-organizational knowledge sharing, reinforcing early stages design iterations to emphasize the maturation of the requirements across supply chain levels. This chapter highlights the uptake of VDD in a traditionally protective domain, such as the aerospace sector. It describes methods and tools for value assessment, and points toward the most relevant initiatives in this domain. Eventually, it discusses areas of further research to promote the effective use of the VDD methodology while designing complex engineering systems.

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  • 32.
    Bertoni, Marco
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Hallstedt, Sophie
    Blekinge Institute of Technology, School of Engineering, Department of Strategic Sustainable Development.
    Isaksson, Ola
    Value assessment of sustainability hotspots in conceptual design: an aerospace study.2014Conference paper (Refereed)
    Abstract [en]

    Nowadays, when designing structural aero-engine components, the engineering team does not only deal with aerodynamics and structural mechanics criteria. Rather, it needs to make more informed decisions based on the value and sustainability contribution of a design concept. This paper proposes a novel approach that combines qualitative sustainability assessment techniques, which are Environmental Impact Assessment (EIA) and Strategic Sustainability Assessment (SSA), with Net Present Value (NPV) analysis to facilitate early stage decision-making in design. A case study, related to the development of a new high-temperature aero-engine component, illustrates how EIA and SSA identify sustainability hotspots for a new product technology, and how NPV is used to assess alternative solution strategies within the hotspot. Within the studied case, the milling process was identified as a sustainability hotspot, therefore two process options - Electro-Chemical Milling (ECM) and Mechanical Milling (MM) - where benchmarked by calculating their NPV in alternative future scenarios, featuring different market and regulatory assumptions. The approach and its constituting models have been preliminarily verified with designers and process owners in co-located industrial workshops.

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  • 33. Bertoni, Marco
    et al.
    Johansson, Christian
    Larsson, Tobias
    Methods and Tools for Knowledge Sharing in Product Development2011In: Innovation in Product Design: From CAD to Virtual Prototyping / [ed] Bordegoni, Monica; Rizzi, Caterina, New York: Springer , 2011, p. 37-53Chapter in book (Refereed)
    Abstract [en]

    The emerging industrial business partnerships, which feature cross-functional and cross-company development efforts, raise the barrier for the establishment of effective knowledge sharing practices in the larger organization. This chapter aims to highlight the role of knowledge as a key enabler for effective engineering activities in the light of such emerging enterprise collaboration models. Knowledge Enabled Engineering (KEE) is presented as an approach to enhance the extended organization’s capability to establish effective collaboration among its parts, in spite of different organizational structures, technologies or processes. KEE is analysed in its constituent parts, highlighting areas, methods and tools that are particularly interesting for leveraging companies’ knowledge sharing capabilities.

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  • 34. Bertoni, Marco
    et al.
    Larsson, Andreas
    Ericson, Åsa
    Chirumalla, Koteshwar
    Larsson, Tobias
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Isaksson, Ola
    Randall, Dave
    The rise of social product development2012In: International Journal of Networking and Virtual Organisations, ISSN 1470-9503, Vol. 11, no 2, p. 188-207Article in journal (Refereed)
    Abstract [en]

    The aim of the paper is to discuss the rising potential of social software to increase the knowledge management capabilities of virtual product development teams. It presents six fundamental transitions, elaborated from the empirical findings, which justify the rise of a more bottom-up, social creation and sharing of engineering knowledge in the virtual organisation. The study suggests that traditional engineering knowledge management approaches alone are not sufficient to support development activities in the virtual organisation, and that such teams display an increasing demand for social, comparatively lightweight and remixable platforms for bottom-up, social creation and sharing of knowledge.

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  • 35. Bjerkén, Christina
    et al.
    Kao-Walter, Sharon
    Ståhle, Per
    Fracture Mechanisms of a Thin Elastic Plastic Laminate2006Conference paper (Refereed)
    Abstract [en]

    The fracture toughness of a polymer-metal laminate composite is obtained by mechanical testing of a specimen containing a pre-crack. The laminate is a material used for packaging. It consists of a thin aluminium foil and a polymer coating. A centre cracked panel test geometry is used. Each of the layers forming the laminate is also tested separately. The result is compared with the measured fracture strength of the individual layers. It is observed that the load carrying capacity increases dramatically for the laminate. At the strain when peak load is reached for the laminate only aluminium is expected to carry any substantial load because of the low stiffness of the LDPE. However, the strength of the laminate is almost twice the strength of the aluminium foil. The reason seems to be that the aluminium forces the polymer to absorb large quantities of energy at small nominal strain. The toughness compares well with the accumulated toughness of all involved layers. Possible fracture of the interface between the layers is discussed.

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  • 36. Brandt, Anders
    A Digital Filter Method for Forced Response Computation2003Conference paper (Refereed)
    Abstract [en]

    Transient forced response of mechanical structures is usually computed using time domain integration. This is often computationally costly, and the numerical precision and stability are concerns. In the present paper, a novel method based on modal superposition, using a new digital filter implementation, is presented. Poles and residues of the model are used as input data, which allows for using data from a finite element model, a lumped parameter model, or from experimental modal analysis. Modal damping can be used if the damping matrix is unknown. With the proposed method, the frequency dependant error can easily be computed, and can be chosen arbitrarily small by selecting proper sampling frequency (time increment). The method is applicable to all linear structures and can be used for stationary or transient input data. Simulation results show that the new method is superior to the alternative methods, at less computational cost.

  • 37. Brandt, Anders
    et al.
    Ahlin, Kjell
    Sampling and Time-Domain Analysis2010In: Sound and Vibration, ISSN 0022-460X , Vol. 44, no 5, p. 13-17Article in journal (Refereed)
    Abstract [en]

    Most noise and vibration measurement and analysis systems are able to record time history signals for subsequent processing. This article deals with some important aspects of recording and processing these data streams in order to maintain analysis integrity.

  • 38. Brandt, Anders
    et al.
    Ahlin, Kjell
    Lagö, Thomas L
    Noise and vibration measurement system basics2006In: SOUND AND VIBRATION, ISSN 0022-460X , Vol. 40, no 4, p. 9-11Article in journal (Refereed)
  • 39. Brandt, Anders
    et al.
    Lagö, Thomas L
    Ahlin, Kjell
    Tuma, Jiri
    Main principles and limitations of current order tracking methods2005In: SOUND AND VIBRATION, ISSN 0022-460X , p. 19-22Article in journal (Refereed)
    Abstract [en]

    Order tracking is a widely used tool for analysis of vibrations generated in vehicle drivetrain components, since many vibrations are related to engine RPMs. In recent years, offline order tracking has become suitable due to enhanced computer speeds. Many methods, some patented, for both online and offline order tracking have been presented over the years. This article reviews some basic ideas behind current methods and compares their main advantages and limitations. Some basic time-frequency concepts and time window effects are reviewed. Questions on suitable tachometers and their number of pulses per revolution are also addressed. The possibility of processing RPM dependent data without tachometers is also discussed.

  • 40. Broman, Göran
    Computational Engineering2003Book (Other academic)
    Abstract [en]

    This book is the main course literature in the course Computational Engineering, which comprises 22,5 ECTS (European Credit Transfer System), within the programme of Master of Science in Mechanical Engineering with emphasis on Structural Mechanics at Blekinge Institute of Technology. The book starts with rather simple numerical methods for ordinary differential equations and ends with advanced topics such as finite element procedures for systems of transient, non-linear and coupled partial differential equations. Several topics from physics and engineering are included to support the study of the numerical methods.

  • 41. Broman, Göran
    Implications of cavitation in individual grooves of spiral groove bearings2001In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 215, no J5, p. 417-424Article in journal (Refereed)
    Abstract [en]

    The pressure distribution in a flat spiral groove thrust bearing obtained from a straightforward solution of the Reynolds equation includes subatmospheric pressure in part of the grooved area, This is masked in the common theory based on the assumption of an infinite number of grooves. Furthermore, the negative contribution to the load capacity from this area is usually small, which may explain why the presence of subatmospheric pressure has not been given much attention in connection with these bearings. Subatmospheric pressure is, however, necessary for liquid-lubricated flat spiral groove thrust bearings of conventional design to work at all at low numbers of grooves, which in turn requires a non-zero cavitation pressure. Cavitation within individual grooves implies non-linearity in, for example, the relation between load capacity and rotational speed of the bearing and limits the obtainable load capacity. This is more pronounced and important to consider at low numbers of grooves (wide grooves) than at high numbers of grooves (narrow grooves), and it is difficult to determine for what number of grooves that reliable prediction of bearing performance can be expected. It depends on the actual value of the cavitation pressure and other parameters that are usually unknown or difficult to account for. To avoid this disadvantage a modified design of liquid-lubricated flat spiral groove thrust bearings is suggested.

  • 42.
    Broman, Göran
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Miljöinslag i grundutbildningen vid Högskolan i Karlskrona/Ronneby1997Other (Other academic)
    Abstract [sv]

    Högskolan i Karlskrona/Ronneby grundades 1989, och är därmed en av Sveriges yngsta högskolor. Grundutbildning bedrivs inom ämnesområdena teknik, datavetenskap, arbetsvetenskap, ekonomi, språk och kultur. Antalet anställda är ca 220 och antalet studenter ca 2500. Utvecklingstakten är hög och fortfarande kännetecknas ledning och personal av pionjäranda och öppenhet för initiativ, vilket varit till glädje också för detta projekt. Tillämpad informationsteknologi ges hög prioritet och finns som ett naturligt inslag i hela högskolans verksamhet. En målsättning är att också integrera miljöaspekter. Genom anslag från Högskolans Grundutbildningsråd till detta projekt påbörjades 1994 miljöintegrering inom 120p-programmet i maskinteknik med inriktning mot utvecklingsteknik, vid Institutionen för Maskinteknik (IMA), och 180p-programmet i fysisk planering, vid Institutionen för Fysisk Planering och Byggteknik (IFB). Biblioteket deltog också från början för att ge stöd åt projektledning och lärare vid deras integreringsarb ete, samt för att miljöintegrera sin egen verksamhet som stöd för personal och studenter även fortsättningsvis. Ett delmål med projektet var att ge deltagande lärare och övrig personal sådana kunskaper om bärkraftig utveckling - och nödvändigheten därav - att de skulle känna engagemang och själva se möjligheterna till miljöinslag i sina respektive ämnen och övriga yrkesuppgifter. Stor vikt lades därför på personalutbildning, som genomfördes i form av en seminarieserie samt genom handledda fortsatta självstudier och deltagande i externa kurser, konferenser och studiebesök. Resultatet blev gott. Nästan alla lärare vid IMA och IFB fick ett ökat engagemang och deltog aktivt i miljöintegreringsarbetet. Engagemanget har också borgat för fortsatt lärande och automatiska kursförbättringar efter projektets slut, vilket var tanken. Synliga resultat är en vidareutvecklad miljögrundkurs, Miljögrunder 5p, obligatorisk i programmet maskinteknik med inriktning mot utvecklingsteknik och tillgänglig även för andra studenter s om fristående kurs, samt nya kursplaner i de ämnen miljöintegrering bedömts mest relevant i de båda programmen. Även i examination, projektrapporter och examensarbeten syns naturligtvis resultat av miljöintegreringen. Totalt har ca hälften av kurserna inom respektive utbildningsprogram direkt berörts av projektet. Genom följdeffekter har i någon mån även övriga delar av programmen påverkats. Studenterna framför vid kurs-utvärderingar och andra diskussioner att de upplever miljöintegreringen som mycket positiv för deras utbildning och ser den som en värdefull merit då de söker jobb. Miljöinslag har kunnat införas utan att de reguljära ämnena tagit skada - alltså i motsägelse till diskussionen om att värdefulla befintliga kunskaper måste trängas undan när någon "nymodighet" ska föras in i en utbildning. Miljöintegreringen har snarare gjort att studenternas motivation för de reguljära ämnena ökat. Denna tulipanaros har kunnat åstadkommas huvudsakligen genom att: - använda grundläggande kunskaper som reguljärt ingår i utbildningsprogrammen, t ex viss naturvetenskap, för att bygga upp en systemsyn genom vilken miljö- och resursproblemens orsaker och lösningar på principiell nivå blir tydliga. - använda denna systemsyn som ett ramverk i vilket detaljkunskaper som reguljärt ingår i utbildningsprogrammen kan inordnas och ges en övergripande mening, varigenom också sambanden mellan olika ämnen blir tydligare. - exemplifiera de reguljära ämneskunskaperna på ett delvis nytt sätt och visa på alternativa tillämpningar för att stimulera studenternas kreativitet beträffande hur deras yrkeskunskaper konkret kan användas för att lösa miljö- och resursproblemen. Den bärande idén med miljöintegreringen har just varit att med ovanstående som förutsättning, så är det främst genom att bli duktiga i klassiska ämnen för ingenjörer och fysiska planerare som ingenjörer och fysiska planerare kan göra den största insatsen för en bärkraftig utveckling. Att göra om dem till "miljöexperter" i traditionell mening vore inte fruktbart. Det Naturliga Stegets definition av bärkraftighet och modell för planering av bärkraftig utveckling, som visat sig så framgångsrik inom näringslivet, har visat sig lämplig även inom den högre utbildningen. Den har utgjort grunden för den systemsyn som använts i detta projekt enligt ovan. Projektet har troligen även bidragit som inspirationskälla, åtminstone som en av flera faktorer, till verksamheter utanför dess ram. Exakt hur mycket är naturligtvis svårt att bedöma. Ökade kunskaper och det allmänt ökade intresset för miljöfrågor har i varje fall lett till allt ifrån konkreta saker som införskaffande av institutionscykel för kortare ärenden och vindkraftverk och solpaneler som komplement till energiundervisningen, till deltagande i internationella miljöutbildningsprojekt, doktorandverksamhet i miljöanpassad produktutveckling, inrättandet av professurer med miljöprofil, och ansvar för högskolans miljöpolicy och miljöplan. Detta utgör naturligtvis omvänt också ett starkt stöd för underhåll och utveckling av miljöintegreringen. Den bedöms därför ha utmärkta förutsättningar att bli bestående vid IMA och IFB och förhoppningsvis sprida sig till övriga institutioner och utbildningsprogram.

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  • 43. Broman, Göran
    et al.
    Hermann, Madeleine
    Jönsson, Anders
    Modelling Bellows Expansion Joints by Standard Beam Finite Elements2000Conference paper (Refereed)
    Abstract [en]

    A procedure for modelling bellows expansion joints by the standard beam finite elements of I-DEAS Master Series 6 is presented. It is shown that the bellows dynamic behaviour can be modelled by beam elements by manipulating certain element parameters. The method will work in any software in which these parameters can be set by the user. Compared to a shell elements model the model size is reduced by at least a factor of 100. This is especially advantageous when the bellows is only a part of a system to be optimised with respect to overall design parameters. In comparison to existing "semi-analytical" methods the beam finite elements have the advantages of considering axial, bending and torsion degrees of freedom simultaneously and that the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements, is easily facilitated. The procedure is verified by experimental results from other investigators.

  • 44.
    Broman, Göran
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Hermann, Madeleine
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Jönsson, Anders
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Modelling Flexible Bellows by Standard Beam Finite Elements1999Report (Other academic)
    Abstract [en]

    A procedure for modelling flexible metal bellows by the standard beam finite elements in I-DEAS Master Series 6 is presented. In spite of the geometry of the bellows being far from a beam, it is shown that the bellows dynamic behaviour can be modelled by beam elements with the suggested procedure. The model size is reduced by a factor of 100-1000 compared to a shell elements model. This is especially advantageous when the bellows is only a part of for example an exhaust system to be optimised with respect to overall design parameters. In comparison to existing "semi-analytical" methods the standard beam finite elements have the advantages that axial, bending and torsion degrees of freedom are included simultaneously and that the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements, is easily facilitated. The procedure is verified by experimental results from other investigators.

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  • 45. Broman, Göran
    et al.
    Holmberg, John
    Robèrt, Karl-Henrik
    Simplicity Without Reduction: Thinking Upstream Towards the Sustainable Society2000In: Interfaces, ISSN 0092-2102, E-ISSN 1526-551X, Vol. 30, no 3, p. 13-25Article in journal (Refereed)
    Abstract [en]

    The natural-step framework is used by over 100 organizations, including many global corporations in Europe and the United States, to provide strategic direction for their sustainability initiatives. The framework is built on the concept of simplicity without reduction. Out of respect for complexity we designed it to provide a compass, a guide for strategic direction. The framework consists of a backcasting planning process for sustainable development based on four principles (system conditions) for sustainability. The framework does not prescribe detailed actions. Once an organization understands the framework it identifies and specifies the detailed means by which to achieve the strategy, because it knows its business best. The steps in the planning process are understanding and discussing the system conditions for sustainability, describing and discussing how the company relates to the system conditions in today's situation, creating a vision of how the company will fulfill its customers' needs in the futur e while complying with the system conditions, and specifying a program of actions that will take the company from today's situation to the future vision.

  • 46. Broman, Göran
    et al.
    Jönsson, Anders
    The Nonlinear Behavior of a Rammer Soil Compactor Machine2000Conference paper (Refereed)
    Abstract [en]

    A theoretical model of a rammer compactor machine is described and its dynamic behaviour is analysed. The differential equations of the model are solved numerically by using standard software. Simulation results are presented as time series, phase plane diagrams, mappings and bifurcation diagrams. The results show that the system is highly nonlinear and indicates that harmonic, subharmonic and chaotic behaviour is present for the parameter variations used. This parameter sensitivity emphasizes the need for this kind of simulations in the product development process.

  • 47. Broman, Göran
    et al.
    Jönsson, Anders
    Hermann, Madeleine
    Determining Dynamic Characteristics of Bellows by Manipulated Beam Finite Elements of Commercial Software2000In: International Journal of Pressure Vessels and Piping, ISSN 0308-0161, E-ISSN 1879-3541, Vol. 77, no 8, p. 445-453Article in journal (Refereed)
    Abstract [en]

    A procedure for determining dynamic characteristics of bellows by manipulating certain parameters of the beam finite elements of I-DEAS Master Series 6 is presented. The method will work in any software in which these parameters can be set by the user. Compared to a shell elements model the model size is reduced by at least a factor of 100. This is especially advantageous when the bellows is only a part of a system to be optimised with respect to overall design parameters. Stress in the bellows cannot be predicted by this method, but when the dynamic behaviour is known it can be used as input for stress calculations, if desired. In contrast to existing "semi-analytical" methods this method has the potential of considering axial, bending and torsion degrees of freedom simultaneously, and it facilitates the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements. The procedure is verified by experimental results from other investigators.

  • 48. Broman, Göran
    et al.
    Jönsson, Anders
    Wall, Johan
    Englund, Thomas
    Introductory Optimisation Study of a Rammer Soil Compactor Machine2001Conference paper (Refereed)
    Abstract [en]

    Rammer compactor machines perform dynamic soil compaction. The complexity of this machine type makes design optimisation through traditional prototype testing impractical. This has pointed to the need for a theoretical model and simulation procedure for prediction of the dynamic behaviour of the machine and a procedure for optimisation as design parameters are changed during product development. In this paper a theoretical model of the rammer machine in combination with a soil model is described. This multi-body dynamics system is solved numerically. The system is non-linear and chaotic behaviour is possible. This parameter sensitivity emphasises the need for this kind of simulations in the product development process. A fairly regular behaviour is necessary for a predictable and safe operation. Parameter combinations giving too irregular behaviour are non-feasible. The energy transfer rate from the rammer machine into the soil is used as the objective function for optimisation. Multi-start Sequential Quadratic Programming for optimum search is used. To cover the design space well a Uniform Experimental Design is used for selection of starting points. This procedure proves to work well for the problem of this introductory study. The study shows a significant potential for improved compaction capacity although considering only the three design parameters that are most easily changed in practice. Approximately the same optimum is obtained both for operation on soft soil and hard soil, so a good all-round design seems possible. Including this theoretical support in the product development process should make it much more effective in finding optimum designs, also for other machines of similar type.

  • 49. Broman, Göran
    et al.
    Rudenko, Oleg
    Submerged Landau jet: exact solutions, their meaning and application2010In: Physics Uspekhi, ISSN 1063-7869, E-ISSN 1468-4780, Vol. 53, no 1, p. 91-98Article, review/survey (Refereed)
    Abstract [en]

    Exact hydrodynamic solutions generalizing the Landau submerged jet solution are reviewed. It is shown how exact inviscid solutions can be obtained and how boundary layer viscosity can be included by introducing parabolic coordinates. The use of exact solutions in applied hydrodynamics and acoustics is discussed. A historical perspective on the discovery of a class of exact solutions and on the analysis of their physical meaning is presented.

  • 50. Broman, Göran
    et al.
    Östholm, Stefan
    Mathcad in Teaching Rotor and Structural Dynamics1997In: International journal of engineering education, ISSN 0949-149X, Vol. 13, no 6, p. 426-432Article in journal (Refereed)
    Abstract [en]

    This paper describes how Mathcad is used to deepen understanding of fundamental aspects in the field of rotor and structural dynamics in two of the undergraduate courses in the education programme of Bachelor of Science in Mechanical Engineering with emphasis on Product Development at the University of Karlskrona/Ronneby, Karlskrona, Sweden. Integrating this mathematical software has clearly given an improved interest for mathematics as well as mechanics among the students.

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