Rapid fabrication of 3D CFRP parts by hot forming of pre-cured CFRP sheets

Abstract

Abstract A precure–hot forming–postcure (P–HF–P) process, in which CFRP prepregs were firstly hot pressed to eliminate its interlayer voids and pre-cured followed by hot formed into 3D shapes and finally post-cured, was proposed for the rapid fabrication of 3D CFRP parts. The void fraction, flexural modulus and strength of different regions of 3D CFRP parts fabricated by P–HF–P and autoclave processes were evaluated. Then the overall axial compression and transverse bending properties of CFRP parts fabricated by different processes were experimentally and numerically investigated. The void fraction, flexural modulus and strength were improved by increasing the pre-curing time of P–HF–P process, and a void fraction of 2.5% and comparable flexural properties were achieved to the autoclave process. CFRP parts manufactured by the P–HF–P process with a pre-curing time of 10 min had comparable overall load-bearing and energy absorption capacities to those fabricated by autoclave process under axial compression and transverse bending. The comprehensive comparison of void fraction, flexural properties, and overall load-bearing capacity and energy absorption ability indicates that the P–HF–P process achieves a better balance between the high productivity and high quality of CFRP products than autoclave process.