Wrinkling prediction of bimetallic composite plates: The unified critical wrinkling judgment line

Wrinkling instability is a significant technical challenge affecting the quality of plastic-forming processes in metal composite plates. The accurate prediction of wrinkling instability holds substantial theoretical and practical value. This study employs a shear wrinkling experiment on bimetallic composite plates and establishes a numerical simulation model using the Buckle + Static-General algorithm in ABAQUS. Experimental comparisons validate the accuracy of the simulation. Based on bifurcation theory and numerical analysis, the critical wrinkling state of the composite plate is determined by the bifurcation time of the stress-strain path in the metal layer with the more significant thickness proportion. Additionally, the stress-neutral layer shift theory confirms that, at the critical wrinkling time, the stress-neutral layer of the composite plate is located within the thicker metal layer. The unified critical wrinkling judgment line of the composite plate is established by extracting the critical wrinkling stress-strain data of the specimens under various stress loading paths. Visualization of wrinkling areas and morphological features is achieved through color mapping, verifying the accuracy of the judgment line. This research provides a robust methodology for predicting wrinkling instability in composite plates.