B. J. Henz¹, D. R. Shires²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.1, pp. 13-18, 2008, DOI:10.3970/icces.2008.007.013

Abstract The capability to predict the residual stresses induced during the manufacturing process in composite components is necessary for the timely fielding of new combat systems. At the U.S. Army Research Laboratory we have developed a computational environment to model the resin flow, heat transfer, curing, and residual stresses in composite components manufactured with the resin transfer molding (RTM) process. This computational environment uses object-oriented programming methods to provide model coupling capabilities and access to high performance computing assets. In this paper we will provide details of the physical models, software, and the validation/verification procedure used More >

N. D. Ngo, K. K. Tamma

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.2, pp. 103-134, 2004, DOI:10.3970/cmes.2004.005.103

Abstract In the process modeling and manufacturing of large geometrically complex structural net-shaped components comprising of fiber-reinforced composite materials by Resin Transfer Molding (RTM), a polymer resin is injected into a mold cavity filled with porous fibrous preforms. The overall success of the manufacturing process depends on the complete impregnation of the fiber preform by the polymer resin, prevention of polymer gelation during filling, and subsequent avoidance of dry spots. Since the RTM process involves the injection of a cold resin into a heated mold, the associated physics encompasses a moving boundary value problem in conjunction More >

R. Mathur¹, S. G. Advani², B. K. Fink³

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.5, pp. 587-602, 2003, DOI:10.3970/cmes.2003.004.587

Abstract Real number-coded hybrid genetic algorithms for optimal design of resin injection locations for the resin transfer molding process are evaluated in this paper. Resin transfer molding (RTM) is widely used to manufacture composite parts with material and geometric complexities, especially in automotive and aerospace sectors. The sub-optimal location of the resin injection locations (gates) can leads to the formation of resin starved regions and require long mold fill times, thus affecting the part quality and increasing manufacturing costs. There is a need for automated design algorithms and software that can determine the best gate and… More >

N. D. Ngo, K. K. Tamma¹

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.3, pp. 57-72, 2000, DOI:10.3970/cmes.2000.001.359

Abstract In the process modeling via Resin Transfer Molding (RTM) for thick composite sections, multi-layer preforms with varying thermophysical characteristics across the different layers, or for geometrically complex mold geometries with varying thicknesses, the assumption of a thin shell-like geometry is no longer valid. The flow in the through thickness direction is no longer negligible and current practices of treating the continuously moving flow front as two-dimensional and the temperature and cure as three-dimensional are not representative of the underlying physics. In view of these considerations, in the present study, the focus is on the non-isothermal… More >