Wrinkling phenomenon during uniaxial extension of a woven thermoplastic composite

In the current research, wrinkling behaviour of a pre-consolidated woven self-reinforced polypropylene (SRPP) composite is investigated. Specimens possessing different aspect ratios were uniaxially extended at room temperature. Principal strains were recorded by a 3D optical photogrammetric system. Continuous measurement of out-of-plane displacements and induced in-plane strains elucidated the effect of specimens' aspect ratios on wrinkling behaviour of SRPP composite. Investigating the evolution of meridian strains offered a valuable insight into development of principal strains before and after wrinkling onset. Plotting major and minor strains in a 2D strain space clarified the role of different deformation modes in the evolution of wrinkles. It was shown that common wrinkling predictors used on metals cannot effectively predict wrinkling initiation in this class of composites and a more reliable measure, based on evolution of local strains, should be employed. The current study investigates the wrinkling behaviour of a woven thermoplastic composite for the first time through a modified Yoshida buckling experiment. The outcomes illustrated effective parameters on the wrinkling evolution in SRPP specimens.