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一、前言在采用上限单元技术(UBET)分析轴对称塑性变形问题时,通常将变形体视为由若干个径向截面呈矩形和直角三角形形状的圆环单元所组成,根据边界条件建立起变形体的动可容速度场,计算出各单元的上限功率分量,然后与外力虚功率相平衡,求出加工载荷的上限值。上限单元技术条理清晰,方法简便,能为塑性成形工艺的计算机辅助设计提供理论依据。在《UBET 应用研究之一》一文中,曾分析了矩形单元速度场及其上限功率分量表达式,
I. INTRODUCTION In the analysis of axisymmetric plastic deformation using UBET technique, the deformation body is usually regarded as consisting of several ring elements with rectangular cross section and rectangular triangle shape, and the deformation is established according to the boundary conditions The dynamic allowable speed field of the body calculates the upper limit power component of each unit and then balances with the virtual power of the external force to find the upper limit of the machining load. The upper limit of the unit technology is clear, the method is simple, can provide a theoretical basis for the computer-aided design of plastic forming process. In the article “One of UBET Applied Research”, we analyzed the rectangular unit velocity field and its upper bound power component expression,