MECHANICAL ANALYSIS OF CYLINDERS BEING UPSET BETWEEN SPHERICAL CONCAVE PLATEN AND CONCAVE SUPPORTING PLATE

Mechanical analysis of cylinders being upset between spherical concave platen and concave supporting plate is conducted.Rigid-plastic mechanical models for cylinders are presented. When the ratio of height to diameter,is larger than 1,there exists two-dimensional tensile stress in the deformed body,when the ratio is smaller than 1,there exists shear stress in static hydraulic zone.The former breaks through the theory that there is three-dimensional compressive stress irrespective of any ratio of height to diameter.The latter satisfactorily explains the mechanism of layer-like cracks in disk-shaped forgings and the flanges of forged gear axles.The representation of the two models makes the upsetting theory into correct and perfect stage.