Creep and stress relaxation behaviour of PLA-PCL fibres-A linear modelling approach

摘要

In the scope of this project, a biodegradable composite was studied as a possible solution for a ligament reinforcement material. The main focus was to analyze the creep and stress relaxation behaviour of poly lactid acid (PLA) blended with poly e-caprolactone (PCL), i.e., PLA-PCL fibres, and investigate the performance of a simple linear viscoelastic mechanical model, the Burgers model, describing both behaviours. Based on the shape of the stress-strain curve, PLA-PCL displays, similarly to the natural ligament tissue, a nonlinear visco-elastoplastic behaviour. The linear viscoelastic approach seemed to be valid up to a certain stress level, assumed to be the linear viscoelastic threshold. Creep and relaxation data suggested that the rate of creep/stress relaxation decreases with increasing stress/strain.