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逆方法 (IA)是一种基于产品最终形状的,应用于构建轴对称冷锻造过程模型的简单方法。由于是假设在简单路径下变形,而且简化了工具的作用形式,因此该方法计算速度很快;数值测试显示,该种方法因为没有考虑变形历史,因而只能较好的估算应变,但是应力估算的误差较大。该文提出了一种新方法——拟逆方法 (PIA:Pseudo Inverse Approach),这种方法是在保留IA优势的基础上,考虑了工件的加载历史,因而可以较好的估算应力。PIA引入了多个中间构型来考虑变形路径,摒弃了传统的接触问题的处理方法,采用自由表面法对中间构型进行修正。另外,基于等效应力的概念和拉伸应力应变曲线,提出了一种全新的塑性积分的直接算法,并编写了快速健强的计算程序。通过和ABAQUS的计算结果的比较,研究了PIA的计算效率和局限性,结果表明,该方法可以应用于初始预成形的设计以及锻造工艺的参数优化。
The inverse method (IA) is a simple method based on the final shape of the product that is used to build a model for an axisymmetric cold forging process. The method is computationally fast because it assumes deformation in a simple path and simplifies the form of the tool. Numerical tests show that this method can only estimate strain well, but does not estimate strain history, but stress estimation The error is larger. In this paper, a new method, Pseudo Inverse Approach (PIA), is proposed. This method considers the loading history of the workpiece based on preserving the advantages of IA, so that the stress can be well estimated. PIA introduces a number of intermediate configurations to consider the deformation path, abandon the traditional approach to deal with the problem of contact, the use of free surface method to amend the middle configuration. In addition, based on the concept of equivalent stress and tensile stress-strain curve, a new direct method of plastic integral is proposed and a fast and robust calculation program is compiled. By comparing with the results of ABAQUS, the computational efficiency and limitations of PIA are studied. The results show that this method can be applied to the design of initial preform and the parameter optimization of forging process.