Residual Stress-Induced Center Wave Buckling of Rolled Strip Metal

In this paper computational and analytical treatments of the center wave buckling phenomenon in thin strips under in-plane loads which typically appear during cold rolling of sheet metal, are presented. Buckling due to self-equilibrating residual stresses, caused by the rolling process, in conjunction with global tensile stresses (due to the traction force acting on the strip) is considered. The shape of the distribution of the residual stresses over the width of the strip influences the buckling mode. Furthermore, it is shown that an increasing global tension force leads not only to increased critical residual stress intensities but also to shorter buckling waves concentrated towards the center of the strip. Taking these facts into account, a proper combination of the information gained from measuring the global tensile force at which buckling appears, the wave length, and some characteristic shape parameters of the buckling pattern allows the estimation of the intensity and the type of the residual membrane force distribution in the strip. By introducing dimensionless quantities, diagrams are provided which can be used for the determination of critical loading combinations, wave lengths, and shape parameters.