Tearing Mode Interlaminar Fracture Toughness of Composite Mateirals

摘要

The Simplified Split Cantilever Beam (SSCB) is proposed in this work and com- pared with the Split Cantilever Beam (SCB) to obtain the tearing mode interlaminar fracture toughness. The materials considered are single-fiber system composites and interply hybrid composites. For interply hybrid composites, three different types of stacking sequence for SSCB specimens. which are IO~oc/O~G/ /0~2C). logc/O~G/ /0~2d, and logc/ogG/ /0~2d. are tested to compare their suitability. Finite element analysis combined with a modified crack closure integral has been applied to separate the different components of the strain-energy release rate. In addition, the method of compliance calibration was used to calculate Gc values. The effects of crack growth. initial crack length, specimen width, and number of glass fiber plies were also studied. The results show that SSCB testing has a more dominant Mode III component and more stable Gc values than SCB testing. For SSCB testing. the crack growth and the specimen width for the range considered have no clear ef- fects on the interlaminar fracture toughness. but the initial crack length should be carefully selected to obtain corrected values. The tearing mode interlaminar frac- ture toughness of interply hybrid composites is higher th8f1 that of carbon/epoxy composites. and the three different types of stacking sequence considered are all suitable to approximate the Mode 111 interlaminar fracture toughness for interply hybrid composites.