面心立方晶体单晶材料弹塑性本构模型

来源期刊：中南大学学报(自然科学版)2004年第3期

论文作者：丁智平 刘义伦 尹泽勇 杨治国 成晓鸣

文章页码：423 - 428

关键词：单晶材料;正交各向异性;屈服准则;弹塑性;本构模型;面心立方

Key words：single crystal material; orthotropy; yield criterion; elastic-plasticity; constitutive model; facecentered cubic

摘    要：基于正交各向异性材料在偏轴受载时存在拉、剪应力耦合效应的影响,通过增加一项由应力偏张量分量的二次乘积项构成的应力不变量,对Hill屈服模型进行修正,并根据面心立方晶体单晶材料的屈服特点提出了新的屈服准则。用新屈服准则对国产DD3单晶合金的屈服应力进行预测,预测结果与试验结果相吻合;新屈服准则与Hill屈服准则相比,在760℃时的预测精度显著提高。在此基础上,重新定义适合新屈服准则的等效应力和等效应变,并由联合流动法则,以屈服函数作为塑性势函数,建立面心立方晶体单晶材料的弹塑性本构模型,推导出相应的弹塑性矩阵。对于各向同性材料,新屈服准及其等效应力和等效应变退化为VonMises屈服准则和其相应的等效应力与等效应变。

Abstract: Taking into account the effects that the components of tension stresses coupled with components of torsion stresseswhen off-axis loads are applied for orthotropic material, Hill’s yield criterion for plastically orthotropic solids is modified by adding an invariant which is composed of quadratic components of deviatoric stress tensor, then a new yield criterion is put forward in term of the characteristics of face-centered cubic (FCC) single crystal material. The correlation to experimental results is very good while the new criterion is used to predict the yield stresses of single crystal nickel-based superalloy DD3,and it is more accurate than Hill’s at 760℃. The equivalent stress and strain which adapt to the new criterion are defined. Thinking of the yield function as a plastic potential function according to the associated flow rule, the elastic-plastic constitutive model for FCC single crystal material is constructed and the corresponding elastic-plastic matrix is educed. The new yield criterion and its equivalent stress and strain will be reduced toVonMises yield criterion and the corresponding equivalent stress and strain for isotropic material respectively.