Effects of fibre misalignment on compressive properties of advanced thermoplastic composites

Compression testing was performed using a novel, inexpensive and reliable compact sandwich beam loaded in four-point bending. Various degrees of fibre misalignment, inherent to four types of PEEK/AS4 prepreg, were measured using the method of Yurgartis. Laminates made from these prepregs, and prepregs with induced in-phase in-plane fibre waviness, were tested to determine the compressive modulus and strength.;Compressive strength and failure strains decreased significantly as fibre misalignment increased. Laminates made from the four types of prepreg had strengths and strains ranging from 1.52 GPa and 1.55%, to over 1.85 GPa and 1.93%, respectively.;It is recommended that the configuration of the compact sandwich beam test be optimized with a view to eventually developing a new standard compression test method. (Abstract shortened by UMI.).;The compressive modulus at zero strain decreased with increasing fibre misalignment. The relatively small range in inherent misalignment corresponded to a modest range in moduli, 122-129 GPa. Laminates with high degrees of induced waviness had moduli as low as 81 GPa. The compliance (reciprocal of modulus) appeared to be a linear function of the mean square fibre angle.