(西北工业大学 机电学院，西安 710072)
摘 要: 正确识别各向异性材料力学性能中的应变硬化指数是金属成形模拟分析的重要部分。针对各向异性材料，讨论了单一方向的应变硬化指数对复杂应力问题求解的局限性，提出了一种基于扩展孔洞模型计算等效应变硬化指数的新方法。基于该方法，以TC1M钛合金板为研究对象，结合数值分析推导出载荷-接触半径曲线斜率变化比与等效应变硬化指数的关系式。通过对比和分析单一硬化指数和等效硬化指数对有限元模拟结果中材料应力应变关系的影响，验证了球形压痕法所得等效应变硬化指数对复杂应力问题的适用性。
关键字: 各向异性板料；应变硬化指数；球形压痕；复杂应力
（School of Mechanical Engineering, Northwestern Polytechnical University, Xi’ an 710072, China）
Abstract:Accurate determination of the strain hardening exponent of the anisotropic materials is the fundamental part of the numerical simulation of metal forming. For anisotropic materials, the limitations were discussed when the single orientation-dependent strain hardening exponent was used in the numerical simulation of multi-stress problems. A new approach based on the expanding cavity model was proposed to identificate the strain hardening exponent of anisotropic materials. Based on this, a new relationship between the variation of the slope ratio of load-contact radius curve and the equivalent strain hardening exponent was suggested for the TC1M titanium alloys sheet, by using the numerical and theoretical analysis. The effectiveness of this method was verified by comparing the numerical results using either the single orientation-dependent strain hardening exponent or the new indentation-based strain hardening exponent. The results show that the equivalent strain hardening exponent is more suitable for the multi-stress state problem.
Key words: anisotropic sheet; strain hardening exponent; spherical indentation; multi-stress state
