Keywords: reactive injection moulding, resin transfer moulding, optimization.

Recently, in the design of technological processes an attention is focused on numerical modelling and if it is possible on optimization of them. Various numerical methods have been used to simulate a progress and development of different processes connected with resin moulding. Such technological processes are especially difficult in numerical description due to complexity of physical processes. Their simulation should include the resin flow in a mould and then its hardening associated with the hardening process of epoxy resin.

In the present paper two technological processes will be discussed in details: the resin transfer moulding (RTM) and the resin injection moulding (RIM). The numerical simulation is conducted with the use of the control volume finite element method – the package FLUENT. The first part of the paper is devoted to the description of governing relation and numerical simulation of the problems. In the RIM both 2-D and 3-D problems are discussed and solved dealing with the filling of 2-D and 3-D moulds having complicated shapes and then hardening. In this area numerical simulations are also compared and verified by experiments where temperature have been measured inside the mould. The second RTM process is especially connected with a 2-D analysis of the resin flow through a porous media (composite material) and then hardening.

With the use of the described above numerical models two optimization problems have been formulated and solved to improve the effectiveness of technological process:

1. To minimize the total time of the RIM process subjected to constraints generated by the requirement of the correctness in the mould filling process; the constraints are mainly characterized by the values of the degree of cure parameter and their distribution in the mould; in order to optimize the problem the heating temperature around the mould varies and is treated as a design variable,
2. To minimize the residual strength arising during the RTM process in composite 2-D structures; in that class of problems both time and temperature of heating and cooling (now constant around the mould) are treated as design variables.

The optimization procedures and algorithms are based on the variants of genetic algorithms that may be successfully implemented in such class of design problems. The results of optimization are demonstrated and discussed and in addition various details connected with the applicability of crossover, mutation and selection methods are proposed. As it may be observed from numerical simulations the effectiveness of the optimizations algorithms are also strongly dependent on the number of population in the process. In order to conduct the optimization the external procedures working independently on the FLUENT [3] procedures have been used herein.

The proposed methods of the optimization analysis are similar to those discuseed in Refs [4,5] where the optimal design have been conducted for composite structures with the use of the FEM.

1

Muc A., Saj P., Numerical optimisation of mould temperature regime in the RTM process, Proc. ICCM/13, Bejing, 2001.

2

Muc A., Saj P., Numerical simulations and optimisation problems for reactive injection moulding process, Proc. ECCM/2, Krakow 2001.

3

FLUENT 5 User's Guide Volume I, Fluent Incorporated, 1998

4

Muc, A., Gurba, W. (2001) Genetic algorithms and finite element analysis in optimization of composite structures, Composite Structures, 54, 2001, pp. 275-281. doi:10.1016/S0263-8223(01)00098-8

5

Muc, A., Gurba, W. (2001) Optimization of volume for composite plated and shell structures, Proc. 3rd Int.Conf. Thin-Walled Str., 8 stron, Elsevier, London 2001, pp. 585-91. doi:10.1016/B978-008043955-6/50064-1

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