(西北工業(yè)大學(xué) 機(jī)電學(xué)院，西安 710072)
摘 要: 正確識(shí)別各向異性材料力學(xué)性能中的應(yīng)變硬化指數(shù)是金屬成形模擬分析的重要部分。針對(duì)各向異性材料，討論了單一方向的應(yīng)變硬化指數(shù)對(duì)復(fù)雜應(yīng)力問(wèn)題求解的局限性，提出了一種基于擴(kuò)展孔洞模型計(jì)算等效應(yīng)變硬化指數(shù)的新方法。基于該方法，以TC1M鈦合金板為研究對(duì)象，結(jié)合數(shù)值分析推導(dǎo)出載荷-接觸半徑曲線斜率變化比與等效應(yīng)變硬化指數(shù)的關(guān)系式。通過(guò)對(duì)比和分析單一硬化指數(shù)和等效硬化指數(shù)對(duì)有限元模擬結(jié)果中材料應(yīng)力應(yīng)變關(guān)系的影響，驗(yàn)證了球形壓痕法所得等效應(yīng)變硬化指數(shù)對(duì)復(fù)雜應(yīng)力問(wèn)題的適用性。
關(guān)鍵字: 各向異性板料；應(yīng)變硬化指數(shù)；球形壓痕；復(fù)雜應(yīng)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
