Manufacturing of CFRP specimens with controlled out-of-plane waviness

Abstract

In this paper, the manufacturing of carbon fibre reinforced plastic laminates with intentionally, re-producibly and mathematically defined high quality out-of-plane waviness made from unidirectional prepreg material is described. This methodology is employed to manufacture tension test specimens with included controlled out-ofplane ply waviness. The waviness ratio is A/L = 0.09, where A and L denote the wave amplitude and the wavelength, respectively. A number of quality assurance verifications is carried out on these specimens before the tension test. These verifications are to corroborate that the realised graded waviness is consistent with the theoretically defined waviness function. The manufacturing process of these specimens is described in detail. The tension test of the specimens is performed by means of a hydraulic testing device. The force–displacement curves of the tension test are plotted to analyse the material behaviours. Experimental investigations are carried out in conjunction with non-destructive 3D optical measurement methodology to identify the failure mechanisms. The results of quality assurance verifications on the specimens exhibit a perfect matching between the geometrically graded shapes and the theoretical function. Furthermore, the results of tension qualification tests show that all specimens have very similar damage behaviour and the failure events have occurred in the waviness area.