Static Compression Failure of Carbon Fibre T800/924C Composite Plate with a Single Hole

Abstract

This paper describes an experimental and theoretical study of the compres sive failure of carbon/epoxy, T800/924C, composite laminates. Static tests were carried out to investigate the mechanics of uniaxial compressive failure in multidirectional unnotched [(±45/0₂)₃] _s plates. Fibre microbuckling in the 0° plies is the critical damage mode which causes fracture of the composite plate. A series of experiments was also carried out to determine the failure in compressively loaded [(±45/0 ₂)₃] _s laminates with circular holes. X-ray radiography and scanning elec tron microscopy were used to observe damage initiation and propagation. Failure is initi ated as matrix cracking. With increasing load fibre microbuckling, surrounded by delami nation, occurs at the edges of the hole at locations of high in-plane compressive stress. When damage reached a critical state the laminate failed catastrophically. Finally, a theoretical model is presented for predicting the static strength of notched laminates. Theoretical predictions are compared with experimental data for specimens containing circular holes of different sizes. Agreement of theory with test data is ac ceptable.