Experimental analysis on membrane wrinkling under biaxial load – Comparison with bifurcation analysis

This paper presents a detailed experimental study of the formation and evolution of the wrinkle pattern that form in flat elastic and isotropic membranes under the action of in-plane tension. The experiments were carried out on a cruciform specimen stretched along two uncoupled axes using various loading paths. The wrinkled shapes of the membrane were digitized by using a full-field measurement based on the fringe analysis method. Over this experiment, several phenomena were observed: the mechanism of wrinkle division, the influence of the membrane thickness on the wrinkle pattern, and the reproducibility of a kinematic configuration of wrinkles. The main result is that non-unique wrinkle shapes have been observed over repeated experiments for nominally identical boundary conditions. The uncertainty of the experimental wrinkle shape has been explained using comparison with the results of a post-buckling finite element analysis.