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冲压时毛坯内部的应力与应力分布,是确定冲压工艺参数、设计工艺过程和冲模、分析和解决冲压件质量问题的基础,也是冲压变形理论研究工作中最基本的任务。虽然目前有各种塑性力学的理论方法可用来解决这类问题,并形成各种学派[1]、[2]、[3]、[4]、[5]、[6],但因为在计算过程中不得不引入的一些简化(如塑性条件、平衡条件、硬化、毛坯尺寸变化等方面),常常可能造成较大的误差,尤其是在形状复杂的零件成形时,在计算上又可能碰到不易克服的困难,使理论分析方法的运用受到很大的限制。为了解决这个问题,本文提出根据冲压时毛坯各部分尺寸变化的结果,利用变形力学的基本原理确定变形毛坯各部分所受应力的数值与分布规律的方法。在一般情况下,根据全应变理论,三向应力状态下的应力与应变之间存在有如下关系
The stress and stress distribution in the blank during stamping are the basis for determining the stamping process parameters, designing the process and the die, analyzing and solving the quality problems of the stamping parts, and also the most basic tasks in the research work of the stamping deformation theory. Although there are various theoretical methods of plastic mechanics that can be used to solve such problems and form various schools [1], [2], [3], [4], [5], [6] Some simplifications that have to be introduced during the process (such as plastic conditions, balance conditions, hardening, variations in the dimensions of the stock) often result in large errors, especially in complex shaped parts that are computationally likely to encounter Difficult to overcome, so that the use of theoretical analysis methods are greatly restricted. In order to solve this problem, this paper proposes the method of determining the value and distribution of stress in various parts of deformed blank by using the basic principle of deformation mechanics according to the result of the change of the size of each part of blank at the time of stamping. Under normal circumstances, according to the theory of total strain, there is the following relationship between stress and strain under three-state stress