💡 Failure of composite components generally falls into one of three classes: design failures, material and manufacturing defects, and in-service anomalies. Hence failure investigation of PMCs will entail collation and analysis of a huge amount of information, but there are demands on the analyst to reach conclusions rapidly and with the minimum expenditure of resources. The important contributing factors for the composite material are summarized here.

🔎Manufacturing defects

The formation of the two types of voids is due to different causes and their size and shape also differ. The dry spot type of void results from the resin not being able to fill all empty spaces within the preform. This can be caused by premature resin crosslinking which affects the resin flow by a local non-uniformity of viscosity. Another cause of the dry spot formation is multiple flow fronts merging and trapping air between them. The entrapped air then prevents the full merger of the flow fronts resulting in unfilled volumes. Yet another cause of dry spot formation is irregular permeability of the preform caused by non-uniformity of the preform geometry or architecture.