受载高聚物裂尖的损伤和银纹化  

CRACK TIP DAMAGE AND CRAZING IN POLYMERS UNDER LOADING

作　　者：罗文波[1] 杨挺青[2] 

机构地区：[1]湘潭大学基础力学与材料工程研究所,湘潭411105 [2]华中科技大学力学系,武汉430074

出　　处：《力学学报》2003年第5期553-560,共8页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(10172037;20204012);湖南省教育厅青年基金(02B005)

摘　　要：采用扫描电子显微镜(SEM),对高聚物裂尖银纹损伤的引发和演化过程进行了原位观测.将固态高聚物本体材料视为线黏弹体,裂尖银纹区视为非线性损伤区,通过构造银纹区的损伤演化方程,给出了银纹区应力模型和银纹生长规律,数值结果与已有实验吻合良好.In situ observation via SEM was conducted to study the crack-tip crazing damage process in polymers under loading. By considering the polymer bulk as linear viscoelastic body and the craze zone at crack tip as a nonlinear damage zone, the control equation for craze zone growth was derived. It is shown that for a time-independent craze-zone stress, the craze zone grows only if the crack-tip stress intensity factor is changed. If the crack-tip stress intensity factor remains constant during loading, the growth rate of the craze zone length will be interrelated to the crack-tip stress, the craze zone length and the rate of change of the craze-zone stress. If both the craze-zone stress and the crack-tip stress intensity factor are time-independent, the craze zone length will be constant during crack growth, which is the case of self-similar crack growth. Moreover, a new stress distribution model in craze zone was presented based on the constructed damage evolution law. The lengthening and thickening of the craze zone at a crack tip was formulated. The numerical calculations from the proposed model agree well with published experimental data.

关 键 词：高聚物本体材料 裂尖 损伤 银纹化 原位观测 扫描电子显微镜 材料力学 黏弹性 

分 类 号：TB324[一般工业技术—材料科学与工程] TB301