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  • 1.
    Carlson, Tony
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Ordéus, D.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    CFRP structural capacitor materials for automotive applications2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, an approach towards realising novel multifunctional polymer composites is presented. A series of structural capacitor materials made from carbon fibre reinforced polymers have been developed, manufactured and tested. The structural capacitor materials were made from carbon fibre epoxy prepreg woven lamina separated by a polymer film dielectric separator. The structural capacitor multifunctional performance was characterised measuring capacitance, dielectric strength and tearing force. The developed structural carbon fibre reinforced polymer (CFRP) capacitor designs employing polymer film dielectrics (PA, PC and PET) offer remarkable multifunctional potential. © Institute of Materials, Minerals and Mining 2011.

  • 2.
    Carlson, Tony
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Ordéus, Daniel
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Structural capacitor materials made from carbon fibre epoxy composites2010Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 70, nr 7, s. 1135-1140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, an approach towards realising novel multifunctional polymer composites is presented. A series of structural capacitor materials made from carbon fibre reinforced polymers have been developed, manufactured and tested. The structural capacitor materials were made from carbon fibre epoxy pre-preg woven laminae separated by a paper or polymer film dielectric separator. The structural capacitor multifunctional performance was characterised measuring capacitance, dielectric strength and interlaminar shear strength. The developed structural CFRP capacitor designs employing polymer film dielectrics (PA, PC and PET) offer remarkable multifunctional potential. © 2010 Elsevier Ltd.

  • 3.
    Ekstedt, Sofia
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Structural batteries made from fibre reinforced composites2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    Structural, fibre reinforced, battery prototypes with two types of electrolyte matrix material, a gel and a solid polymer, have been manufactured. This was to confirm the concept of using carbon fibres as current collector in the anode as well as providing a mechanical load-carrying functionality. As a result, functioning batteries with gel electrolyte have been produced and their properties have been characterised.

  • 4.
    Ekstedt, Sofia
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Structural batteries made from fibre reinforced composites2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Structural, fibre reinforced, battery prototypes with two types of electrolyte matrix material (a gel and a solid polymer) have been manufactured. This was to confirm the concept of using carbon fibres as current collector in the anode as well as providing a mechanical load-carrying functionality. As a result, functioning batteries with gel electrolyte have been produced and their properties have been characterised. © 2010 Maney Publishing.

  • 5.
    Farajzadeh Khosroshahi, S.
    et al.
    University of Padova, Italy.
    Olsson, Robin
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Zaccariotto, M.
    University of Padova, Italy.
    Galvanetto, U.
    University of Padova, Italy.
    Response of a helmet liner under biaxial loading2018Ingår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 72, s. 110-114Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Helmets are the most effective protective item for motorcyclists. The liner of the helmet is the part of the helmet which dissipates most of the impact energy and mitigates the risk of head injuries. It has been proposed that the helmet test standards should include assessment of the helmets for oblique impacts that is not currently addressed in the standards. A conventional uniaxial compression test method is still used for characterization of the helmet liner material. However, compressive tests of EPS foams provide reliable results for normal loading on EPS, but do not provide a realistic result for oblique impacts. Therefore, we carried out experimental tests to measure the response of EPS foams, which are commonly used for helmet liners, under biaxial loading. The result of our experiments show that the shear response of EPS foams is a function of axial compression, and increasing the axial strain leads to increased shear stiffness, and thus higher levels of shear stress. We also showed that including shear-stiffening of EPS in the FE assessment of helmets may change the headform rotational acceleration by 25%. Therefore, such behavior of EPS foams should be included in FE analysis of helmets in the case of oblique impacts for a more realistic assessment of their performance.

  • 6.
    Larijani, Nasim
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Marklund, Erik
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Metal onto polymer composite casting: Degradation behaviour and mechanical performance2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    A general three dimensional finite element model for modelling thermal degradation of polymer composites due to thermal loading is presented. In particular, the model is intended for modelling the thermal degradation of polymer composites due to "metal onto composites casting" with lightweight alloys. The model is implemented as a user defined subroutine into the general purpose FEpackage ABAQUS©. The applicability of the code was demonstrated by analysing the casting process of an aluminium alloy onto composite rods, resulting in a shrinkage fit. To succeed in manufacturing of this type of joint, a delicate balance between thermal loadings, metal shrinkage, composite degradation and the overall cooling must be met. The proposed subroutine together with finite element models provides the spatial distribution of these field variables, allowing for subsequent optimization of the assembly. In order to asses the quality of the composite/metal joints pull-out tests of cylindrical composite rods were performed and compared to numerical simulation predictions.

  • 7.
    Larsson, R.
    et al.
    Chalmers University of Technology.
    Rouhi, Mohammad
    Chalmers University of Technology.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Free surface flow and preform deformation in composites manufacturing based on porous media theory2012Ingår i: European journal of mechanics. A, Solids, ISSN 0997-7538, E-ISSN 1873-7285, Vol. 31, nr 1, s. 12-janArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present contribution an infusion simulation tool is developed, applicable to a quite wide range of composites manufacturing technologies. The paper focusses on isothermal, infusion like manufacturing processes involving highly deformable preforms and a free surface resin flow. There are two major issues addressed at the modelling of the infusion processes: The first one is the highly deformable preform and its shape due to the interaction between external pressure loading and the intrinsic fluid pressure. The second issue concerns the migrating free surface due to resin infiltration into the fibrous preform. To resolve these both issues simultaneously, a compressible two-phase porous media formulation is put forward involving an additional liquid mass balance relationship as compared to the standard compressible porous media formulation. As a result a governing equation for saturation degree evolution is established, which is used to monitor the free surface problem directly in terms of the compressible continuum formulation traversing into incompressibility with increasing partial saturation degree. A staggered finite element based solution procedure is advocated for the total solution advancement, involving, on the one hand, the saturation dependent porous media formulation, and, on the other hand, the computation of the saturation degree. The proposed formulation has been implemented and numerical results are provided, showing the convergence of the staggered approach, and the assessment of the proposed approach against a 1D analytical model. In addition, the infusion of a "hat" beam is considered. © 2011 Elsevier Masson SAS. All rights reserved.

  • 8. Larsson, Ragnar
    et al.
    Rouhi, Mohammad
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Infusion modelling using two-phase porous media theory2010Konferensbidrag (Övrigt vetenskapligt)
  • 9. Larsson, Ragnar
    et al.
    Rouhi, Mohammad
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Modeling resin flow and preform deformation in composite manufacturing based on partially saturated porous media theory2010Konferensbidrag (Övrigt vetenskapligt)
  • 10. Larsson, Ragnar
    et al.
    Rouhi, Mohammad
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Resin Flow and Preform Deformation in Composites Manufacturing Based on a Partially Saturated Porous Medium2011Konferensbidrag (Övrigt vetenskapligt)
  • 11.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Costa, Sergio
    RISE., Swerea.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Gutkin, Renaud
    Chalmers University of Technology, Sweden.
    Coupling process and structural simulations in crash application2016Ingår i: 31st ASC Technical Conference and ASTM D30 Meeting, 2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The energy absorbed during crushing of composite structures is strongly dependent on the layup, fiber architecture and type of resin used. Modeling of the crash behavior of composites is therefore highly influenced by the composite material system chosen, and current constitutive models must be improved to include/account for the inherent properties from the manufacturing step. The ultimate goal of this contribution is to optimize the material system and manufacturing method for the required crushing performance in terms of energy absorption and cost. A first outcome of the study will be to provide information regarding the properties of the final manufactured composite material such as residual stresses and effects of defects. These properties are then used in the development of crash models. A robust link between manufacturing, experiments and crushing simulations is vital where there should be a generic routine towards the data transfer and constitutive models. The study of effects of defects will affect the input data into the material and constitutive models in form of change in strength and stiffness properties of the material. In this contribution, an experimental study on the material response under quasistatic crushing is performed where the manufacturing effects on the material properties are considered based on estimated data provided from vacuum infusion simulation. The crushing simulations are performed with ABAQUS where the material model developed in-house, which is a physically based damage model based on the LaRC05 failure criterion and progressive damage, is chosen to model the constitutive behavior. The parameters that are transferred to the system from manufacturing simulation are fiber content and voids. Consideration of these parameters into the constitutive behavior of the structure will directly influence the structural response. A parametric study is completed and results are discussed.

  • 12.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Juntikka, Magdalena
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Landberg, Johan
    RISE - Research Institutes of Sweden, Material och produktion, IVF.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Assessing models for the prediction of mechanical properties for the recycled short fibre composites2019Ingår i: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 38, nr 10, s. 454-466Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Processing of polymer fibre composites has a remarkable influence on their mechanical performance. These mechanical properties are even more influenced when using recycled reinforcement. Therefore, we place particular attention on the evaluation of micromechanical models to estimate the mechanical properties and compare them against the experimental results of the manufactured composites from recycled carbon fibre material. For the manufacturing process, an epoxy matrix and carbon fibre production cut-offs as reinforcing material are incorporated using a vacuum infusion process. In addition, continuous textile reinforcement in combination with the epoxy matrix is used as reference material to evaluate the degradation of mechanical performance of the recycled composite. The experimental results show higher degradation of the composite strength compared to the stiffness properties. Observations from the modelling also show the same trend as the deviation between the theoretical and experimental results is lower for stiffness comparisons than the strength calculations. Yet still, good mechanical performance for specific applications can be expected from these materials.

  • 13.
    Rouhi, Mohammad S.
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP. Chalmers University of Technology, Sweden.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP. Chalmers University of Technology, Sweden.
    Larsson, Ragnar
    Chalmers University of Technology, Sweden.
    Experimental assessment of dual-scale resin flow-deformation in composites processing2015Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 76, s. 215-223Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we are concerned with the assessment of sub-models within a two-phase continuum mechanical FE framework for process modeling of composites manufacturing. In particular, the framework considers the inclusion of two deformation dependent models describing resin flow related to: (1) meso-scale wetting and compaction of individual plies and (2) overall preform deformation and macroscopic Darcian flow. Using micro-mechanical modeling, we model the physics of these sub-processes in relation to the recently developed Out-Of-Autoclave (OOA) prepergs. The models are placed in context with a compression–relaxation experiment, employed to study the preform deformations considered separated from other sub-processes. Finally, calibrations and model validations are carried out against the relaxation experiment to relate the FE framework to the mechanical response of the preform. Therefore, using the above experiment, parameter values out of the literature and those estimated from micrographs gave a fair agreement between the simulation and experiments.

  • 14.
    Rouhi, Mohammad S.
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP. Chalmers University of Technology, Sweden.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP. Chalmers University of Technology, Sweden.
    Larsson, Ragnar
    Chalmers University of Technology, Sweden.
    Holistic modeling of composites manufacturing using poromechanics2016Ingår i: Advanced Manufacturing: Polymer & Composites Science, ISSN 2055-0340, Vol. 2, nr 1, s. 14-26Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    AbstractIn the present paper, we present a novel finite-element method capable of handling most of the physics arising in the resin wet-out step for any composite system and processing case. The method is based on a compressible two-phase continuum formulation where a key feature is to model the involved physics via innovative use of the compressibility of the phases. On the one hand, the fluid-phase compressibility is used to capture the physics of the advancing resin front as well as the physics behind the flow front. On the other hand, solid-phase compressibility is used to model micro-infiltration of the resin and the corresponding preform compaction, essentially considered as a fluid sink problem. Finally, the generic porous media model is formulated in the finite strain regime. The model is implemented and demonstrated for different manufacturing methods and the results with respect to each example are presented. The degree of saturation, pressure distribution, preform deformation, and reaction forces are some of the post-processed results for different manufacturing methods. The ultimate goal of this contribution is to establish a unified generic and general simulation tool for structural (long fiber) composite processing where, to this date, there is no single FE-based tool available commercially for this purpose.

  • 15.
    Rouhi, Mohammad S.
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Larsson, Ragnar
    Modeling of coupled dual-scale flow–deformation processes in composites manufacturing2013Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 46, s. 108-116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present contribution is a part of the work towards a framework for holistic modeling of composites manufacturing. Here we focus our attention onto the particular problem of coupled dual-scale deformation–flow process such as the one arising in RTM, Vacuum Assisted Resin Infusion (VARI) and Vacuum Bag Only (VBO) prepregs. The formulation considers coupling effects between macro-scale preform processes and meso-scale ply processes as well as coupling effects between the solid and fluid phases. The framework comprises a nonlinear compressible fiber network saturated with incompressible fluid phase. Internal variables are introduced in terms of solid compressibility to describe the irreversible mesoscopic infiltration and reversible preform compaction processes. As a main result a coupled displacement–pressure, geometrically nonlinear, finite element simulation tool is developed. The paper is concluded with a numerical example, where a relaxation–compression test of a planar fluid filled VBO preform at globally un-drained and partly drained conditions is considered.

  • 16.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    SIMULATION OF 3D PREPREG CONSOLIDATIONPROCESS USING SOLID SHELL ELEMENTS2018Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In process simulation of composite materials, 3D simulation of manufacturing processes is desirableconsidering the manufacturing trend where parts became more complex leading to complex3D stress-strain states. Moreover, coupling of sub-processes that are happening simultaneouslysuch as macro-scale preform processes, micro-infiltration and solid and fluid interactionrequires full 3D description of the problem.The development is exemplified considering compression moulding process of prepregs wherethe main focus of the modeling will be on the compression and compaction of directionalprepreg laminate and flow consolidation. To this end, the theory of two phase porous mediais used along with assuming hyper-elastic material response for the laminate to formulatethe problem. A finite element formulation and implementation of the two-phase problem is developedfor incompressible constituents and is implemented in a user defined element (UEL)to be used with Abaqus.

  • 17.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Larsson, R.
    Chalmers University of Technology.
    Modeling of coupled dual-scale flow-deformation processes in composites manufacturing2013Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 46, nr 1, s. 108-116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present contribution is a part of the work towards a framework for holistic modeling of composites manufacturing. Here we focus our attention onto the particular problem of coupled dual-scale deformation-flow process such as the one arising in RTM, Vacuum Assisted Resin Infusion (VARI) and Vacuum Bag Only (VBO) prepregs. The formulation considers coupling effects between macro-scale preform processes and meso-scale ply processes as well as coupling effects between the solid and fluid phases. The framework comprises a nonlinear compressible fiber network saturated with incompressible fluid phase. Internal variables are introduced in terms of solid compressibility to describe the irreversible mesoscopic infiltration and reversible preform compaction processes. As a main result a coupled displacement-pressure, geometrically nonlinear, finite element simulation tool is developed. The paper is concluded with a numerical example, where a relaxation-compression test of a planar fluid filled VBO preform at globally un-drained and partly drained conditions is considered. © 2012 Elsevier B.V. All rights reserved.

  • 18.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    larsson, Ragnar
    Composite manufacturing modeling using porousmedia theory2012Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    We recently developed a simulation tool to simulate a quite wide class ofcomposites manufacturing processes based on a compressible porous media theory formulationinvolving three constituents, solid, fluid and pore gas embedded in the voids. The aim of thistool is: firstly to model the highly deformable preform and its interaction with external loadingand the intrinsic fluid pressure as well as the resulting changes in permeability, compaction andlevel of saturation. Secondly, the aim is to track the resin flow front during the infusion processusing the continuum formulation itself, thereby avoiding methods like level set

  • 19.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Larsson, Ragnar
    Modeling resin flow, preform deformations and residual stresses in RTM manufacturing2011Konferensbidrag (Övrigt vetenskapligt)
  • 20.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Larsson, Ragnar
    MODELING THE CONSTITUTITVE REPONSE OFAN ANISOTROPIC DUAL-SCALE FLOW2012Konferensbidrag (Övrigt vetenskapligt)
  • 21.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Larsson, Ragnar
    PROCESS MODELING OF COMPOSITEMATERIALS - A HOLISTIC AND GENERICSIMULATION TOOL USING POROMECHANICS2014Konferensbidrag (Övrigt vetenskapligt)
  • 22.
    Rouhi, Mohammad
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Larsson, Ragnar
    Chalmers University of Technology, Sweden.
    SIMULATION OF 3D RTM PROCESS USING SOLID SHELL ELEMENT2016Ingår i: 13th International Conference on Flow Processes in Composite Materials (FPCM 13), 2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In the era of process modeling of composite materials, 3D simulation of manufacturing processesis desirable considering the manufacturing trend where parts became more complexleading to complex 3D stress-strain states. Moreover, coupling of sub-processes that are happeningsimultaneously such as macro-scale preform processes, flow advancement and solidand fluid interaction requires full 3D description of the problem.The development is exemplified considering RTM process where the main focus of the modelingwill be on the flow advancement into fiber preform and flow front capturing. To thisend, the theory of two phase porous media is used along with assuming hyper-elastic materialresponse for the fiber bed to formulate the problem. A finite element formulation and implementationof the two-phase problem is developed for incompressible constituents

  • 23.
    Saseendran, Sibin
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Varna, Janis
    Luleå University of Technology, Sweden.
    Effect of degree of cure and time on viscoelastic poisson's ratio2017Ingår i: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Poisson's ratio of a solid under deformation is classically defined as the negative of the ratio between the lateral or transverse strain and the axial strain. Ideally for an elastic material, the Poisson's ratio is assumed to be a constant. However, for viscoelastic materials like polymers and polymer matrix composites this is also likely influenced by various factors like time [1], temperature, degree of cure and also on the strain. In this work, the evolution of the viscoelastic Poisson's ratio of the commercial LY5052 epoxy resin is studied under uniaxial tension subject to constant deformation stress relaxation testing. Measurements of the Poisson ratios are performed using contact extensometers and strain gages. Samples at five different cure states are manufactured and investigated. The relaxation testing is performed by loading the samples to 0.5% longitudinal strain and monitoring the relaxation behavior over a period of 24 hours per cure state. Poisson's ratio is observed to evolve from 0.32 to 0.44 over time depending on the cure state. Moreover the data indicates that the individual Poisson's ratio curves can be shifted horizontally following time-cure superposition. The shift functions used for this horizontal shifting are similar to those identified for DMTA tests for storage modulus under identical conditions. Following horizontal shifting, master curves that show the evolution of Poisson's ratio over time can be created for a particular reference cure state. This similarity of the shift functions in both micro-scale DMTA testing and macro-scale relaxation testing is an indicator of the validity of the shift factors. The observation is used to further develop a viscoelastic model which identifies the total shift function as the product of the temperature and cure shift functions. 

  • 24.
    Saseendran, Sibin
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Varna, Janis
    Luleå University of Technology, Sweden.
    Evolution of viscoelastic behaviour of a curing LY5052 epoxy resin in the rubbery state2017Ingår i: Advanced Composite Materials, ISSN 0924-3046, E-ISSN 1568-5519, Vol. 26, nr 6, s. 553-567Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, we investigate the relationship between the rubbery modulus and the degree of cure for partially to fully cured LY5052 epoxy resin. In particular, this paper experimentally tests an existing model formulated for shear modulus by redefining for in the tensile storage modulus. Experiments to characterize viscoelastic behaviour were performed in a dynamic mechanical and thermal analysis (DMTA) instrument in the frequency domain. Master curves are then created from DMTA using general time–temperature–cure superposition. The master curves are then normalized using the model so that the master curve does not depend on the properties in the rubbery region. This results in a unique master curve that describes the viscoelastic behaviour of the LY5052 epoxy resin for the given conditions. Once the relationship between the rubbery modulus and the degree of cure has been established, the amount of experimental characterization can be reduced. This could lead to the development of simplified experimental methodologies and simplified models to characterize the viscoelasticity of low molecular weight resins like the LY5052 epoxy resin system.

  • 25.
    Szpieg, Magdalena
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Development and characteristics of a fully recycled CF/PP composite2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    A fully recycled carbon fibre reinforced polypropylene (rCF/rPP) composite material has been developed and characterised. This new, randomly oriented short fibre composite was manufactured by press forming with a fibre volume fraction of 40 %. A series of tensile tests using rectangular specimens cut in four different directions (0°, 90°, ±45°) in the composite plate were performed to confirm in-plane material isotropy. Models to predict stiffness and strength of the short fibre rCF/rPP composite were also employed and validated using experiments. To model the viscoelastic and viscoplastic responses of the composite, an inelastic material model was employed and characterised using a series of creep and recovery tests. From the creep tests, it was found that the time and stress dependence of viscoplastic strains follows a power law. The viscoelastic response of the composite was found to be linear in the investigated stress range. The material model was validated in constant stress rate tensile tests and the agreement was good, even close to the rupture stress.

  • 26.
    Szpieg, Magdalena
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Mechanical performance and modelling of a fully recycled modified CF/PP composite2012Ingår i: Journal of composite materials, ISSN 0021-9983, E-ISSN 1530-793X, Vol. 46, nr 12, s. 1503-1517Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A fully recycled carbon fiber reinforced maleic anhydride grafted polypropylene (MAPP)-modified polypropylene (rCF/rPP) composite material has been developed and characterized. This new composite was manufactured employing papermaking principles, dispersing the recycled carbon fibers (rCF) in water, and forming them into mats. Two layers of the recycled polypropylene (rPP) films manufactured using press-forming were sandwiched between three rCF preform layers in a stack. The stack was heated and press-formed resulting in a composite plate with a nominal thickness of 1.20 mm and a fiber volume fraction of 40%. A series of tensile tests using rectangular specimens cut in four different directions (0°, 90°, ± 45°) in the composite plate were performed to confirm in-plane material isotropy. Models to predict stiffness and strength of the short fiber rCF/rPP composite were also employed and validated using experiments. The models were found to be in good agreement with experimental results. Fiber length distribution measurements were performed before (unprocessed) and after (processed) composite manufacturing to investigate the influence of processing on fiber degradation. The results revealed a significant reduction in fiber length by the press-forming operation. To model the viscoelastic and viscoplastic responses of the composite an inelastic material model was employed and characterized using a series of creep and recovery tests. From the creep tests, it was found that the time and stress dependence of viscoplastic strains follows a power law. The viscoelastic response of the composite was found to be linear in the investigated stress range. The material model was validated in constant stress rate tensile tests and the agreement was good, even close to the rupture stress. © The Author(s) 2011.

  • 27.
    Szpieg, Magdalena
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Novel composites from recycled constituents2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    Only a small fraction of the waste generated by use and manufacturing of carbon-based composites is currently reused. However, due to European Union (EU) regulations and limited amount of landfilling, the industry is forced to consider recycling solutions already during the manufacturing process. The following work is devoted to the development of a technique for manufacture of novel engineering materials from recycled carbon fibres and thermoplastic matrix. Fibre preforms are manufactured employing a papermaking technique for dispersing the carbon fibres. The polypropylene (PP) matrix was reprocessed into a film. The carbon fibre preforms and PP films were stacked and composite materials were subsequently manufactured by press forming and evaluated.

  • 28.
    Szpieg, Magdalena
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Recycled polypropylene aimed as composites precursor material2009Ingår i: Plastics, rubber and composites, ISSN 1465-8011, E-ISSN 1743-2898, Vol. 38, s. 412-418Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this research is to assess the stability and processability of recycled polypropylene (PP) materials for their suitability for use as matrix material in polymer composite. The work comprises development and characterisation of matrix precursors from recycled PP. The reused PP considered comes from two sources: PP from the self-reinforced PP Pure processing scrap and an automotive grade developed to offer an even material quality. To assess the thermal stability of two PP qualities for subsequent composite manufacturing, oxidation induction time (OIT), melting point Tm, decomposition temperature 7d and viscosity μ were investigated. The results indicate, that Pure processing scrap is very well stabilised and therefore suitable for multiple processing, whereas the automotive grade recycled PP cannot be used for this purpose. Fibres for subsequent composite preforming were spun by melt spinning from the Pure scrap processing and its mechanical properties were characterised. © Institute of Materials, Minerals and Mining 2009.

  • 29.
    Szpieg, Magdalena
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Wysocki, Maciej
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Reuse of polymer materials and carbon fibres in novel engineering composite materials2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    The present work was devoted to the development of a technique for manufacture of a novel engineering material from carbon fibres and thermoplastic matrix recyclates. Fibre preforms were manufactured employing a papermaking technique for dispersing the carbon fibres. The polypropylene (PP) matrix recyclate was reprocessed into a film. The carbon fibre preforms and PP films were stacked and composite materials were subsequently manufactured by press forming. The mechanical behaviour of carbon fibre preforms was characterised by a compaction test and compared to the results obtained by consolidation test of the carbon fibres reinforced PP composites. The consolidation experiments were found to follow the trend from compaction tests allowing prediction of the amount of polymer material needed, fibre volume fraction as well as composites thickness. The resulting dispersion of fibres and void content were evaluated by microscopy. © 2009 Institute of Materials, Minerals and Mining.

  • 30.
    Wysocki, Maciej
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Toll, S.
    Chalmers University of Technology.
    Larsson, R.
    Chalmers University of Technology.
    Two phase continuum modelling of composites consolidation2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, a finite element (FE) code for modelling of pressure driven axisymmetric consolidation of composite material from commingled yarns is presented. The proposed model is developed on the basis of a two phase continuum model incorporated in an FE framework. The applicability of the code to axisymmetric geometries is demonstrated by analysis of the consolidation, i.e. resin infiltration and fibre bundle network deformation, of a GF/PP pressure vessel. In this numerical example, two different sets of processing conditions are presented. Based on these analysis results conclusions on the process ability of the investigated vessel configuration and manufacturing scheme are drawn and processing recommendations are given. © Institute of Materials, Minerals and Mining 2009.

  • 31.
    Wysocki, Maciej
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Larsson, R.
    Chalmers University of Technology.
    Toll, S.
    Chalmers University of Technology.
    Modelling the consolidation of partially impregnated prepregs2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    A finite element model is developed to solve consolidation problems for composites manufacturing. The model is developed from a generic two-phase continuum theory allowing for coupling between the solid and fluid responses. The code is applied to a case study consisting of consolidation of a hat stringer to evaluate nonlinear effects.

  • 32.
    Wysocki, Maciej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Rouhi, Mohammad
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Vyas, Gaurav
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Toll, Staffan
    KTH Royal Institute of Technology, Sweden.
    Constitutive models for transversely isotropic fibreprefrom in composite manufacturing2016Ingår i: 13th International Conference on Flow Processes in Composite Materials (FPCM 13), 2016, artikel-id 20Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The present contribution is an attempt to model a prepreg that is assumed to have approximatelystraight and parallel fibers which in an unloaded state has a transversely isotropicsymmetry about the fiber axis n. It is further assumed that the prepreg behaves elastic undera purely volumetric deformation, as well as under axial stretching in the fiber direction.A two-scale flow highly coupled to the fiber bed deformation is also being modelled usingporomechanics. The framework comprises a nonlinear compressible fiber network saturatedwith incompressible fluid phase.

  • 33.
    Wysocki, Maciej
    et al.
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Szpieg, Magdalena
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Hellström, Peter
    RISE - Research Institutes of Sweden, Material och produktion, SICOMP.
    Ohlsson, F.
    Oxeon AB, Sweden.
    The out-of-plane behaviour of spread-tow fabrics2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper the constitutive compressive behaviour of nearly parallel spread-tow textile reinforcement is studied. The striking result of our analysis is that the spread-tow type of reinforcement should obey linear relation between force and deformation. This is in contrast to standard textile reinforcements that obey a power-law type of behaviour. To support the theoretical investigation we have developed an test rig who's chief purpose is to achieve compression between nearly perfectly parallel surfaces. This is achieved using a mechanical arrangement consisting of a ball-joint.

  • 34.
    Wysocki, Maciej
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Toll, S.
    Chalmers University of Technology.
    Larsson, R.
    Chalmers University of Technology.
    Press forming of commingled yarn based composites: The preform contribution2007Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 67, s. 515-524Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The process of press forming commingled yarn composites is studied and modelled based on the theory of porous media. Two sub processes are considered: (1) the wetting and compaction of individual bundles and (2) the overall preform deformation. An experimental method is introduced, to study these two sub processes separately. The experiment suppresses the fluid pressure build-up, and thus the process of wetting and bundle compaction, by draining the resin into a porous wall. In consequence, the measured response consists only of the preform contribution. Finally, the total response is simulated and tested against independent consolidation experiments. It was demonstrated that the present approach gives better predictions compared to models based on the bundle response only. © 2006 Elsevier Ltd. All rights reserved.

  • 35.
    Wysocki, Maciej
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Toll, S.
    KTH Royal Institute of Technology.
    Larsson, R.
    Chalmers University of Technology.
    Asp, Leif
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Anisotropic and tension-compression asymmetric model for composites consolidation2010Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 41, nr 2, s. 284-294Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A constitutive model for anisotropic and tension-compression asymmetric response of a fibrous preform is developed and solved using a FE software. Applicability of the method to complex geometries is demonstrated by analysis the consolidation of an axisymmetric filament wound pressure vessel made from commingled yarns. Three different winding patterns are considered. In conclusions, the consolidation of the whole vessel, except at the opening, is prevented by the loading mode, where the pressure is applied on the interior. To succeed in manufacturing of this type of pressure vessel, use of an oversized preform that allows extension in the fibre direction is suggested. © 2009 Elsevier Ltd. All rights reserved.

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