Evaluating the shear component of reinforcement compaction stress during liquid composite moulding processes

During the compression of fibrous preforms for complex part geometries, a shear component of the reinforcement compaction stress is present in addition to the normal component. Consideration of the shear stress is required when modelling the forces experienced by mould tools used for liquid composite moulding processes, as they contribute significantly to the total clamping force required during reinforcement compression for high draw angle geometries. The friction coefficient between glass-fibre reinforcements and various mould surfaces has been evaluated. Processing parameters, such as mould closing speed, fibre volume fraction and number of layers of reinforcement, have little influence on the magnitude of the friction coefficient. The presented results validate the use of a simple friction model within liquid composite moulding process simulations.