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- Rouhi, Mohammad Sadegh, 1983, et al.
(författare)
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Composite manufacturing modeling using porous media theory
- 2012
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Ingår i: 25th Nordic Seminar on Computational Mechanics (NSCM25), Lund, Swede, 25-26 October 2012. ; , s. 295-298
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Konferensbidrag (refereegranskat)abstract
- We recently developed a simulation tool to simulate a quite wide class of composites manufacturing processes based on a compressible porous media theory formulation involving three constituents, solid, fluid and pore gas embedded in the voids. The aim of this tool is: firstly to model the highly deformable preform and its interaction with external loading and the intrinsic fluid pressure as well as the resulting changes in permeability, compaction and level of saturation. Secondly, the aim is to track the resin flow front during the infusion process using the continuum formulation itself, thereby avoiding methods like level set.
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- Rouhi, Mohammad Sadegh, 1983, et al.
(författare)
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CONSTITUTIVE MODELLING OF ANISOTROPIC TWO-SCALE FLOW
- 2012
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Ingår i: 15th European Conference on Composite Material (ECCM15) - Venice- Italy 2012. - : European Conference on Composite Materials, ECCM.
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Konferensbidrag (refereegranskat)abstract
- We recently developed a simulation tool to simulate a quite wide class of infusion processes based on a compressible porous media theory formulation involving three constituents, solid, fluid and pore gas embedded in the voids. The aim of this tool is: firstly to model the highly deformable preform and its interaction with external loading and the intrinsic fluid pressure as well as the resulting changes in permeability, compaction and level of saturation. Secondly, the aim is to track the resin flow front during the infusion process using the continuum formulation itself, thereby avoiding methods like level set, etc. [1]. In this contribution, we present a permeability model applied within the modeling framework to account for anisotropic flow in the fibre bed. The ultimate goal of the approach is to be able to simulate the infusion of high performance, large scale composite structures, in an optimized and controlled fashion.
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- Rouhi, Mohammad Sadegh, 1983, et al.
(författare)
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Experimental assessment of coupled dual-scale flow-deformation processes in composites manufacturing
- 2015
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Ingår i: Composites Part A: Applied Science and Manufacturing. - : Elsevier BV. - 1359-835X. ; 76, s. 215-223
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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- Rouhi, Mohammad Sadegh, 1983, et al.
(författare)
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FE modeling and numerical implemtation of flow-deformation processes in composites manufacturing
- 2013
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Ingår i: ICCM International Conferences on Composite Materials. - : International Committee on Composite Materials. ; 2013-July, s. 5292-5299, s. 5292-5299
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Konferensbidrag (refereegranskat)abstract
- In present work, we attempt to unify the modeling of different sub-processes under the umbrella of two-phase porous media theory. Two sub processes are considered: (1) the wetting and compaction of individual plies and (2) the overall preform deformation and macroscopic Darcian flow. The idea is to identify a set of relevant constituents, i.e. particles, voids and liquids, and assign them to pertinent media. The result is a set of overlapping continuous media, each having its own density-, velocity- and stress field on the macroscopic scale. In addition, we introduce internal variables to describe irreversible micro-processes in the system, such as microscopic infiltration and preform deformation. In this work we extend the previous developments, coupling the preform deformation on different scales to the process of micro infiltration, with respect to the modeling of the micro-compaction as well as the Darcian interaction on the macro scale. A coupled displacement-pressure, geometrically non-linear, finite element model is presented. The approach is applied to a representative numerical example where we used parameter values out of the literature and estimates from our own micrographs.
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- Rouhi, Mohammad Sadegh, 1983, et al.
(författare)
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Holistic modeling of composites manufacturing using poromechanics
- 2016
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Ingår i: Advanced Manufacturing: Polymer and Composites Science. - : Informa UK Limited. - 2055-0359 .- 2055-0340.
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Tidskriftsartikel (refereegranskat)abstract
- In the present paper we present a novel finite element method capable of handling most of thephysics arising in the resin wet-out step for any composite system and processing case. The methodis based on a compressible two-phase continuum formulation where a key feature is to model theinvolved physics via innovative use of the compressibility of the phases. On the one hand, thefluid phase compressibility is used to capture the physics of the advancing resin front as well asthe physics behind the flow front. On the other hand, solid phase compressibility is used to modelmicro infiltration of the resin and the corresponding preform compaction, essentially consideredas a fluid sink problem. Finally, the generic porous media model is formulated in the finite strainregime. The model has been implemented and demonstrated for different manufacturing methodsand the results with respect to each example is presented. The degree of saturation, pressuredistribution, preform deformation and reaction forces are some of the post-processed results fordifferent manufacturing methods. The ultimate goal of this contribution is to establish an unifiedgeneric and general simulation tool for structural (long fiber) composite processing where, to thisdate, there is no single FE based tool available commercially for this purpose.
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| 10. |
- Rouhi, Mohammad Sadegh, 1983, et al.
(författare)
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Modeling of coupled dual-scale flow–deformation processes in composites manufacturing
- 2013
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Ingår i: Composites Part A: Applied Science and Manufacturing. - : Elsevier BV. - 1359-835X .- 1878-5840. ; 46:1, s. 108-116
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Tidskriftsartikel (refereegranskat)abstract
- The present contribution is a part of the work towards a framework for holistic modeling of compositesmanufacturing. 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 VacuumBag Only (VBO) prepregs. The formulation considers coupling effects between macro-scale preform processesand meso-scale ply processes as well as coupling effects between the solid and fluid phases. Theframework comprises a nonlinear compressible fiber network saturated with incompressible fluid phase.Internal variables are introduced in terms of solid compressibility to describe the irreversible mesoscopicinfiltration and reversible preform compaction processes. As a main result a coupled displacement–pressure, geometrically nonlinear, finite element simulation tool is developed. The paper is concludedwith a numerical example, where a relaxation–compression test of a planar fluid filled VBO preform atglobally un-drained and partly drained conditions is considered.
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