A MULTISCALE APPROACH OF CALCULATING INITIAL FAILURE AND RESIDUAL STRESSES IN CFRP

摘要

A combined experimental and numerical study has been carried out in order to study the mechanism of initial failure in transversely loaded CF/epoxy composites. A low temperature-curing matrix optimised for RTM technology was investigated. Three-point bending experiments on macroscopic composite specimen with special laminate lay-ups were carried out in a scanning electron microscope (SEM). The In-situ experiments allow observing the onset of microscopic composite failure under transverse loading and measurement of the global applied load at onset of failure. The experimental results show that interfacial failure was the dominating failure mechanism. The interfacial stresses at initiation of failure were determined successfully by a non-linear micro/macro FE-Analysis (FEA). The results were compared with experimental results and the results obtained by using CLT. The results show that the interfacial normal strength (INS) between fibre and matrix governs failure under bending load.