The Role of Semi-Curing in Liquid Composite Moulding

Abstract

This study investigates how Semi-Cured interfaces form and preform in Liquid Composite Moulding processes in order to support the drive towards low cost and high rate manufacture of complex composites. A two-step program was devised. Firstly, the effect on neat resin toughness properties arising from additional thermal cycling needed for Semi-Curing was explored. This confirmed that the Semi-Curing process had little effect on plane-strain fracture toughness values. Secondly, Semi-Cured laminates with elements initially cured to varying degrees of cure were manufactured and tested in Mode I and Mode II. The results of these tests indicated interfacial properties are fully retained in Mode II and a reduction in Mode I is seen after the resin enters the post-gel stage. These initial results demonstrate the usefulness of Semi-Curing to integrate preforms up until the gel point of the material.