Wrinkle behavior of automobile thin sheet metals by modified Yoshida buckling test

In order to study the wrinkling behavior of automobile thin steel sheets under non-uniform tensile stresses, both the hardware and software systems for modified Yoshida buckling test are set up to determine critical wrinkling value and estimate the wrinkling resistant ability. The continuous measurement of wrinkle height Δh at the center, load F and strain λ₄₀ at the gauge length of specimens is realized, the relation curves of Δh-F, F-ΔL and Δh-λ₄₀ are gained, and the initiation and growth of wrinkling is analyzed. The results show that the whole wrinkling sequence consists stages of in-plane deformation, critical deformation, post-buckling break, post-buckling growth, dropping of load, and steep wrinkling.