Simulating the effect of temperature elevation on clamping force requirements during rigid-tool Liquid Composite Moulding processes

Abstract

Moulds used for rigid-tool Liquid Composite Moulding (LCM) processes, namely Resin Transfer Moulding (RTM) and Compression RTM, are often subjected to large internal forces which originate due to resin injection and from the compaction of fibre reinforcements. Appropriate clamping equipment (e.g. press or perimeter clamps) is necessary to equilibrate these forces. An optimal selection (or design) of such clamping equipment calls for an accurate prediction of the tooling forces generated. This work aims to introduce a comprehensive numerical scheme which addresses this issue, including the case of non-isothermal mould filling. A hybrid Finite Element/Finite Difference (FE/FD) methodology is utilised for solving the coupled flow/energy/species equations. A new fibre compaction model, developed in order to reduce computational complexity while maintaining solution accuracy, is implemented into the simulation algorithm. The force predictions obtained for a planar axisymmetric part reveal that the chosen combination of mould and resin temperatures, together with other process variables, plays a crucial role in allowing fast fill times while keeping setup costs low.