THE METHOD OF THE PRINCIPAL SHEAR-STRESS TRACING LINE AND ITS APPLICATION IN THE FLARING AND EXPANDING OF A THIN-WALLED TUBE WITH A CONICALPUNCH

In this paper, the method of the principal shear stress tracing line i s presented. The changing rule of the normal stress along the principa l shear stress tracing line is described first by the normal stress eq uation. This method is applied in solving the problem of the typical p rocesses of thin-walled tube forming with a conical punch, its results being the same as the results given by the slab method. The essential point of this method is to extend the idea that slip-line held theory treats just a pair of orthogonal tracing lines of the maximum shear s tress to one of the three pairs of orthogonal principal shear stress t racing lines. Thus, the method of principal shear stress tracing line has led to the development of the theory of slip-line fields. (C) 1997 Elsevier Science S.A.