Modelling Tow Impregnation of Woven Fabric Reinforcements and Its Application in Liquid Composite Moulding Process Modelling

2008 ◽  
Author(s):  
Y. Wang ◽  
S. M. Grove ◽  
M. Moatamedi
Keyword(s):  
Woven Fabric ◽  
Scale Model ◽  
Flow Front ◽  
Moulding Process ◽  
Mathematical Algorithm ◽  
Model Liquid ◽  
Liquid Composite Moulding ◽  
Sink Term ◽  
Time Required ◽  
Dual Scale

This paper proposes a detail physical model for the micro-scale flow in plain woven reinforcements. The modelling results are formulated into a mathematical algorithm which is then directly incorporated into a continuum dual-scale model as a ‘sink’ term. When used to model liquid composite moulding (LCM) processes, this incorporated dual-scale model demonstrates the fact that the impregnation of fibre tows lags behind the resin front in macro pore spaces. The modelling results are in agreement with the experimental observations. It has been shown that the unsaturated region at the flow front could increase or have a fixed length under different circumstances. These differences are explained due to the variation in tow impregnation speed (or the time required for the tow to become fully impregnated) which is related to the weave infrastructure and the nesting and packing of plies. The modelling results have also demonstrated the drooping of the inlet pressure when the flow processes are carried out under constant injection rates.

The Resin Radial Flow Numerical Simulation in Dual-Scale Porous Fibre Media at Constant Pressure

2013 ◽  
Vol 756-759 ◽  
pp. 44-48
Author(s):  
Xiao Jiang Chen ◽  
Si Jia Guo ◽  
Wen Yan Yan ◽  
Shi Lin Yan
Keyword(s):  
Radial Flow ◽  
Constant Pressure ◽  
Control Volume ◽  
Control Volume Method ◽  
Mass Balance Equation ◽  
Flow Front ◽  
Sink Term ◽  
Single Scale ◽  
Volume Method ◽  
Dual Scale

In this paper, setting up a mathematical model about LCM process based on the theory, which contains a sink term in the mass balance equation of the fluid dynamics. In two-dimensional mold, the finite element/control volume method is used to simulate the flow front and pressure distribution of the flowing resin in single-scale and dual-scale porous media at constant pressure.

scholarly journals A Numerical Analysis of Resin Flow in Woven Fabrics: Effect of Local Tow Curvature on Dual-Scale Permeability

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 405
Author(s):  
Hatim Alotaibi ◽  
Masoud Jabbari ◽  
Constantinos Soutis
Keyword(s):  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Void Formation ◽  
Fibre Volume ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Resin Flow ◽  
Liquid Composite Moulding ◽  
Proposed Model ◽  
Dual Scale

Permeability is a crucial flow parameter in liquid composite moulding (LCM), which is required to predict fibre impregnation, void formation and resin back flow. This work investigates the dual-scale (micro- and meso-) nature of permeability during resin infusion into woven fabric by incorporating the intra tow flow where the degree of local tow curvature (tow/yarn undulation) is taken into account. The mesoscopic permeability of a dual-scale porous media in a unit cell is estimated using Darcy’s law, where the Gebart analytical model is applied for the intra tow flow in longitudinal and transverse directions with respect to distinct fibre packing arrangements. The results suggest that for a low fibre volume fraction (≤42%), the degree of local curvature at the mesoscale can be neglected. However, for a high fibre volume fraction (>42%) and a higher fibre bundle curvature, the proposed model should be adopted, since the resin flow is affected by a mesoscopic tow curvature that could result in around 14% error in predicting permeability. It is shown that the permeability results of the current study are in good agreement with and in the range of the retrieved available experimental data from the literature.

scholarly journals Ply fragmentation in unidirectional hybrid composites linked to stochastic fibre behaviour: A dual-scale model

2019 ◽  
Vol 181 ◽  
pp. 107702 ◽  
Author(s):  
Francisco Mesquita ◽  
Yentl Swolfs ◽  
Stepan V. Lomov ◽  
Larissa Gorbatikh
Keyword(s):  
Hybrid Composites ◽  
Scale Model ◽  
Unidirectional Hybrid ◽  
Dual Scale

scholarly journals Analysis of the Blank Holder Force Effect on the Preforming Process Using a Simple Discrete Approach

2013 ◽  
Vol 554-557 ◽  
pp. 441-446 ◽  
Author(s):  
Walid Najjar ◽  
Xavier Legrand ◽  
Philippe Dal Santo ◽  
Damien Soulat ◽  
Serge Boude
Keyword(s):  
Process Parameters ◽  
Material Behavior ◽  
Woven Fabric ◽  
Physical Parameters ◽  
Angle Distribution ◽  
Forming Process ◽  
Plane Shear ◽  
Blank Holder ◽  
Moulding Process ◽  
Discrete Approach

Simulation of the dry reinforcement preforming, first step of the Resin Transfer Moulding process, become necessary to determine the feasibility of the forming process, compute the fiber directions in the final composite component, and optimize process parameters during this step. Contrary to geometrical approaches, based on fishnet algorithms, finite element methods can take into account the actual physical parameters, the real boundary conditions and the mechanical behavior of the textile reinforcement. The fabric can be modeled either as continuum media with specific material behavior [5, 6], or using discrete structural elements to describe the textile structure at the mesoscopic scale. A semi-discrete approach, which is a compromise between the above continuous and discrete approaches, is also used for simulation. A discrete approach for the simulation of the preforming of dry woven reinforcement has been proposed and presented in a previous paper. This modelling is based on a “unit cell” formulated with elastic isotropic shells coupled to axial connectors. The connectors, which replace bars or beams largely studied in other discrete approaches, reinforce the structure in the yarn directions and naturally capture the specific anisotropic behavior of fabric. Shell elements are used to take into account the in-plane shear stiffness and to manage contact phenomena with the punch and die. The linear characteristic of the connectors, has been extended to a non linear behaviour in the present paper to better account for fabric undulation. Using this numerical model, we propose, in this work to study the effect of process parameters on the woven fabric deformation during the performing step. The emphasis will be placed on the analysis of the influence of the blank holder pressure on the shear angle distribution.

On the Use of a Dual-Scale Model to Improve Understanding of a Pharmaceutical Freeze-Drying Process

2010 ◽  
Vol 99 (10) ◽  
pp. 4337-4350 ◽  
Author(s):  
Valeria Rasetto ◽  
Daniele L. Marchisio ◽  
Davide Fissore ◽  
ANTONELLO A. Barresi
Keyword(s):  
Freeze Drying ◽  
Scale Model ◽  
Drying Process ◽  
Dual Scale

scholarly journals How necessary is a fast testkit for mitigation of pandemic flu?

2009 ◽  
Vol 7 (48) ◽  
pp. 1033-1047 ◽  
Author(s):  
Juxin Chin ◽  
Geoffrey Koh ◽  
Dong-Yup Lee
Keyword(s):  
Influenza Pandemic ◽  
Vital Role ◽  
Diagnostic Methods ◽  
Contact Tracing ◽  
Scale Model ◽  
Global Pandemic ◽  
Pandemic Flu ◽  
Time Required ◽  
The Cost ◽  
Mathematical Modelling And Simulation

It is widely feared that a novel, highly pathogenic, human transmissible influenza virus may evolve that could cause the next global pandemic. Mitigating the spread of such an influenza pandemic would require not only the timely administration of antiviral drugs to those infected, but also the implementation of suitable intervention policies for stunting the spread of the virus. Towards this end, mathematical modelling and simulation studies are crucial as they allow us to evaluate the predicted effectiveness of the various intervention policies before enforcing them. Diagnosis plays a vital role in the overall pandemic management framework by detecting and distinguishing the pathogenic strain from the less threatening seasonal strains and other influenza-like illnesses. This allows treatment and intervention to be deployed effectively, given limited antiviral supplies and other resources. However, the time required to design a fast and accurate testkit for novel strains may limit the role of diagnosis. Herein, we aim to investigate the cost and effectiveness of different diagnostic methods using a stochastic agent-based city-scale model, and then address the issue of whether conventional testing approaches, when used with appropriate intervention policies, can be as effective as fast testkits in containing a pandemic outbreak. We found that for mitigation purposes, fast and accurate testkits are not necessary as long as sufficient medication is given, and are generally recommended only when used with extensive contact tracing and prophylaxis. Additionally, in the event of insufficient medication and fast testkits, the use of slower, conventional testkits together with proper isolation policies while waiting for the diagnostic results can be an equally effective substitute.

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