Numerical analysis of the flatness of thin, rolled steel strip on the runout table

A finite element analysis of the flatness of thin, rolled steel strip is presented. The occurrence of edge-wave and centre-buckle is predicted numerically by solving the eigenvalue problem. The form of buckles is calculated using a non-linear load-displacement analysis. Buckling changes from the centre to the edge as the maximum difference in temperature between the edge and centre increases; correspondingly, the amplitude increases and the wavelength decreases. Because uniform applied tension then decreases the compressive stress at the edge and increases the stress in the centre, a centre-buckled strip is flattened by applied tension, but edge-buckling becomes more severe and applied tension may change the type of buckling from the centre to the edge. Crowned strip resists buckling whereas a concave profile tends to promote it. The effects of the magnitude of the crown or concavity on centre-buckling of the strip are more significant than on edge-buckling.