不同残余应力场中静载压痕周围的塑性区问题  

Plastic zone around indentation under different residual stress

作　　者：孟宪陆[1] 陈怀宁[1] 林泉洪[1] 黄春利 

机构地区：[1]中国科学院金属研究所,辽宁沈阳110016 [2]国电郑州机械设计研究所,河南郑州450052

出　　处：《兵器材料科学与工程》2007年第6期50-53,共4页Ordnance Material Science and Engineering

摘　　要：压痕应变法由于其测试的方便性和准确性而受到越来越多的重视。该方法通过测量压痕周围弹性区应变增量,利用事先获得的应力应变关系求出残余应力大小。因而如何准确确定不同状态下压痕周围塑性区的尺寸对该方法具有重要意义。采用有限元模拟方法对不同应力场状态下,静载方法制造的压痕周围塑性区大小进行分析。发现在单向应力场中,当应力数值从最大压缩变化到最大拉伸时,沿受力方向的塑性区尺寸逐渐减小而垂直受力方向的尺寸逐渐增大。在双向应力场中,塑性区的变化规律比较复杂,但最大尺寸均小于最大拉伸。在研究不同应力场作用下压入载荷撤离前后塑性区的变化时发现,卸载回弹造成的塑性区尺寸变化不明显。本研究结果为确定压痕应变法测量残余应力时的应变栅位置提供依据。The indentation-strain method,as a new technique used for residual stress measurment,has got more and more attention due to its feasibility and accuracy. In this method,the residual stress was determined by the strain increment measured in elastic zone around the indentation ,and compared with the related coefficients achieved in advance. So it is very important to know the shape and dimensions of plastic zone around an indentation in varying stress field. A finite element method is used to analyze plastic zones under static load indentation. It has been found that under axial stress, the size of plastic zone which is parallel to stress decreases, but increases in the normal direction,when the residual stress changed from maximum compresssive stress to maximum tensile stress. Under biaxial stress,the shape of plastic zone is becoming rather complicated, but the maximum size of plastic zone is less than that in axial stress. The change of plastic zone size is not significant before and after loading under any stress field. These results offer the way to fix on the position of gage lines around the indentation during measuring residual stresses.

关 键 词：压痕应变法 有限元 塑性区 残余应力 

分 类 号：TB302.5[一般工业技术—材料科学与工程] TG113.251[金属学及工艺—物理冶金]