杯形件反挤压变形力的滑移线场数值分析解

Numerical analysis of deforming force for the backward extrusion process based on slip-line field theory

因工程设计中挤压力的计算依赖于经验公式,误差较大且不利于优化设计,基于经典塑性理论,运用数学方法探索更准确方便的挤压力的求解模型。以滑移线场为理论平台,以杯形件反挤压过程为研究对象,分析不同压缩比的系列滑移线特征并叠加得到代表滑移线场。在求解应力场及变形力的基础上,通过曲线拟合方法研究滑移线场参数与模具几何参数的解析关系,从而建立变形物理参数与几何参数的数值分析模型。该数值分析模型所得解析解比滑移线场数值解具有更明显的物理意义,在知道变形几何参数的前提下,可方便求解挤压力。最后通过实测挤压力、并结合经验公式进行验证。结果表明数值分析模型计算结果较准确,并可作为目标函数实现工艺优化设计。

The calculation of deforming force depends on experience formula in extrusion process design.It may leads to large calculation error and can not be used in optimization design.Based on the classical plasticity theory,a more accurate and convenient calculation model of extrusion force was studied by mathematical methods.Based on slip line field theory,the backward extrusion process with a cup-shaped mold was studied.Series slip-line field features of different compression ratio were analyzed and superposed.The stress field and deforming force were calculated.The analytical relationship between slip-line field parameters and mold geometrical parameters were analyzed.In this way,the numerical analysis model of the deformation physical parameters of geometric parameters was established.The analytical solution obtained by the numerical analysis model has more obvious physical significance than that by the slip-line field method.If deformation geometric parameters are known,the analysis model could be conveniently used to solve extrusion force.Finally,the extrusion force was also measured with experiments and combined with experience formula for verification.The results showed that the numerical analysis model calculation results were more accurate,which could be used as an objective function to realize processing optimization design.