The implications of fiber compaction and saturation on fully coupled VARTM simulation

Vacuum Assisted Resin Transfer Molding (VARTM) is a process by which resin is drawn through fiber preforms in a one-sided mold using an induced pressure gradient. Although the approach to model flow in VARTM is similar to the Resin Transfer Molding (RTM) process, modeling in VARTM can be significantly more complex if one accounts for fiber compaction and the dual scale nature of the fiber preform which is present in RTM but often neglected. This article investigates the influence of fiber compaction and fiber tow saturation during mold filling in the VARTM process. A non-rigid control volume is used to formulate a set of governing equations to describe the resin flow. Tow impregnation at the micro-scale is coupled with global resin flow at the macroscale by applying conservation of mass principles. Preform compaction is modeled as a non-linear spring bed where compaction pressure is dynamically distributed between the resin and the preform. The variation in preform permeability is modified due to the changes in the fiber volume fraction as a result of changing compaction. A simple one-dimensional mold filling case is solved to investigate the role of compaction and dual scale porous media in VARTM processes. A parametric study allows us to identify situations in which one can neglect compaction and saturation and conditions under which a fully coupled model should be applied for satisfactory results.

[1]  B. R. Gebart,et al.  Permeability of Unidirectional Reinforcements for RTM , 1992 .

[2]  R. R. Sullivan.  Specific Surface Measurements on Compact Bundles of Parallel Fibers , 1942 .

[3]  T. Chou,et al.  Compaction of woven-fabric preforms in liquid composite molding processes: single-layer deformation , 1999 .

[4]  Suresh G. Advani,et al.  A numerical model to predict fiber tow saturation during liquid composite molding , 2003 .

[5]  Woo Il Lee,et al.  Analysis of vacuum bag resin transfer molding process , 2001 .

[6]  M. V. Bruschke,et al.  A finite element/control volume approach to mold filling in anisotropic porous media , 1990 .

[7]  S. Advani,et al.  A Simple Model for the Variation of Permeability due to Partial Saturation in Dual Scale Porous Media , 1997 .

[8]  Suresh G. Advani,et al.  Fabric structure and mold curvature effects on preform permeability and mold filling in the RTM process. Part II. Predictions and comparisons with experiments , 2000 .

[9]  I. Verpoest,et al.  Compressibility and relaxation of a new sandwich textile preform for liquid composite molding , 1999 .

[10]  S. Advani,et al.  A Model for Unsaturated Flow in Woven Fiber Preforms during Mold Filling in Resin Transfer Molding , 1998 .

[11]  R. R. Sullivan.  Further Study of the Flow of Air Through Porous Media , 1941 .

[12]  Tsu-Wei Chou,et al.  Experimental and theoretical studies of fabric compaction behavior in resin transfer molding , 2001 .

[13]  Ben Wang,et al.  Flow modeling and simulation of SCRIMP for composites manufacturing , 2000 .

[14]  Constantina Lekakou,et al.  Compression in the processing of polymer composites 1. A mechanical and microstructural study for different glass fabrics and resins , 1999 .

[15]  T. Gutowski,et al.  Resin flow/fiber deformation experiments , 1986 .

[16]  Tsu-Wei Chou,et al.  A nonlinear compaction model for fibrous preforms , 2001 .

[17]  Suresh G. Advani,et al.  Fabric structure and mold curvature effects on preform permeability and mold filling in the RTM process. Part I. Experiments , 2000 .

[18]  F. Trochu,et al.  Simulation of Compression Resin Transfer Molding with Displacement Control , 1998 .

[19]  P. Carman.  Fluid flow through granular beds , 1997 .

[20]  C. M. van Wyk,et al.  20—NOTE ON THE COMPRESSIBILITY OF WOOL , 1946 .

[21]  F. Trochu,et al.  Numerical analysis of the resin transfer molding process by the finite element method , 1993 .

[22]  François Robitaille,et al.  Compaction of textile reinforcements for composites manufacturing. I: Review of experimental results , 1998 .

[23]  George S. Springer,et al.  Resin Flow During the Cure of Fiber Reinforced Composites , 1982 .

[24]  J. G. Williams,et al.  Liquid flow through aligned fiber beds , 1974 .

[25]  C. Browning.  Composite Materials: Quality Assurance and Processing , 1983 .

[26]  Suresh G. Advani,et al.  Flow of generalized Newtonian fluids across a periodic array of cylinders , 1993 .

[27]  Suresh G. Advani,et al.  Numerical simulation of unsaturated flow in woven fiber preforms during the resin transfer molding process , 1998 .

[28]  Calculation of Cure Process Variables During Cure of Graphite/Epoxy Composites , 1983 .

[29]  Timothy G. Gutowski,et al.  The Consolidation of Laminate Composites , 1987 .