The In-Plane Compression Response of Thermoplastic Composites: Effects of High Strain Rate and Type of Thermoplastic Matrix

Designing thermoplastic composites for particular uses requires understanding their dynamic mechanical behaviour, which affects how well they operate in practical settings. The Split Hopkinson pressure bar (SHPB) test allows for evaluating these materials’ responses to high strain rates. In this study, an in-situ laser-assisted fibre placement (LAFP) machine has been utilised to produce laminate composites with varied designs, i.e., different angles of layers [0/45/–45/90]4s, using three types of thermoplastic tapes (UD-CF/PPS, UD-CF/PEEK, and UD-CF/PEKK). Using a servo-hydraulic testing machine and SHPB apparatus, we have examined the dynamic compressive behaviour of thermoplastic laminate composites with various matrices (PPS, PEEK, and PEKK) in in-plane directions and at strain rates of approx. 0.001, 0.1, 10, 800, 1800/s. Experimental results indicate that the type of thermoplastic matrix and strain rate significantly affect how the laminate composites behave. The in-plane compressive strength and modulus increase approximately linearly with the strain rate. According to the fracture of morphological pictures, the main failure mechanism of all three types of specimens is shear failure under in-plane compression loads, which is followed by delamination and burst.
Keywords: high strain rate; compression properties; PEEK; PEKK; PPS; SHPB test