Numerical Simulation on the influence of solidification rate on mechanical properties of semi-crystalline thermoplastic composites

As with the consolidation time, the cooling rate applied during the solidification stage of the composite processing cycle influences the total processing cycle time, as well as the mechanical performance. By controlling the solidification rate, changes in the matrix morphology and crystallinity can be achieved, and hence different mechanical properties may be obtained. Control of the solidification rate is also important in order to control the level and distribution of internal stresses generated within the part during processing. These stresses may cause the composite to warp, resulting in unsatisfactory part quality, and can lead to premature failure of the part, necessitating costly repair or replacement. Therefore, this chapter emphasises the necessity of controlling the solidification rate, and examines its influence on the mechanical properties and the dimensional stability of composites based on CF/PA12 commingled yarns. The influence of solidification rate on crystallinity, morphology, and resulting mechanical properties of thermoplastic composites has become the subject of many research investigations over the last decade. Transverse tensile tests were performed to examine the influence of the solidification rate on the mechanical properties of the CF/PA12 laminates based on commingled yarns. In order to study the influence of solidification rate on interlaminar fracture toughness, mode I interlaminar fracture tests were carried out using the double cantilever beam (DCB) method, Interlaminar fracture toughness. Key-Words: Thermoviscoelasticity, Finite element modeling, semi-crystalline, Interlaminar fracture, Crystallinity, Composite processing