材料变形中应力三轴性和Lode参数分布演化的数值观测  

Numerical investigation on stress triaxiality and Lode parameter evolution during mechanical history in flat grooved plate and flat notched plate

作　　者：景峥[1,2] 李永池[1,2] 

机构地区：[1]中国科学技术大学近代力学系,安徽合肥230027 [2]中国科学院材料力学行为和设计重点实验室,安徽合肥230027

出　　处：《中国科学技术大学学报》2013年第9期723-729,共7页JUSTC

基　　金：中国博士后科学基金(2011M501394)资助

摘　　要：应力三轴性T和Lode参数θ是影响材料韧性断裂的重要参数,凹纹平板和缺口平板两种试件由于其对于这两个参数有较好的控制能力,被用来观测T和θ在材料变形中的演化规律.对不同尺寸的试件进行了有限元数值模拟,结合等效塑性应变ε和三轴性T的分布和演化,参考双曲线断裂准则,判断可能发生初始断裂的区域并标示具有代表性的节点.对这些节点的T和θ随ε的变化曲线进行分析比较,得出结论:T和θ在缺口平板试件中比在凹纹平板试件中展现出更平稳的演化特点;凹纹平板中心由于其为平面应变状态,θ值为0;随着缺口平板的圆槽半径FNP-R增大,其应力三轴性T将减小,Lode参数θ将越小.Stress triaxiality T and Lode parameter 0 are significant factors affecting the damage behavior of ductile material. Because of the ability of well controlling on value of T and 0, flat grooved plate （FGP） and flat notched plate （FNP） are chosen to investigate the distribution and development of those two factors during the mechanical histories of material. The configurations near the area of groove and the notch of the specimens varied so that different values of T and θ were captured. Numerical simulations were conducted on specimens considering various configurations. And based on the distribution and development of T and θ, using bi-curve failure criterion, potential areas with initial failure were found, where the nodes with high possibilities of initial failure were marked. The curves of T and θ versus ε at marked nodes were depicted and compared, h was shown that the values of T and θ develop in a stable manner in FNP, which is helpful for the calibration of failure criteria, and that θ is around zero as a result of plane strain in FGP, and that the increasing of the diameter of FNP-R decreases the value of T and 0, and θ is closing to -1 in FNP.

关 键 词：凹纹平板 缺口平板 应力三轴性 Lode参数 数值模拟 初始断裂单元 

分 类 号：O346.12[理学—固体力学]