蠕变硬化材料中Ⅱ型扩展裂纹尖端场特性研究  

STUDY OF CHARACTERISTICS OF MODE Ⅱ PROPAGATION CRACK TIP FIELD IN CREEPING MATERIALS WITH HARDENING EFFECT

作　　者：贾斌[1] 李永东[2] 王振清[3] 

机构地区：[1]哈尔滨工业大学航天学院,哈尔滨150001 [2]装甲兵工程学院机械工程系,北京100072 [3]哈尔滨工程大学建筑工程学院,哈尔滨150001

出　　处：《固体力学学报》2009年第2期209-215,共7页Chinese Journal of Solid Mechanics

摘　　要：采用弹粘塑性力学模型,对蠕变硬化材料中平面应变扩展裂纹尖端场进行了渐近分析.假设人工粘性系数与等效塑性应变率的幂次成反比,通过量级匹配表明应力和应变均具有幂奇异性,奇异性指数由粘性系数中等效塑性应变率的幂指数唯一确定.通过数值计算讨论了Ⅱ型准静态扩展裂纹尖端场的分区构造以及裂纹尖端应力和应变场的特性随各材料参数的变化规律,结果表明裂尖场由材料的粘性和塑性共同主导.当硬化系数为零时裂尖场可退化为相应的HR场.An elastic-viscoplastic constitutive mode is adopted to analyze asymptotically the tip-field of moving crack in creeping materials with hardening effect under plane strain condition. Under the assumption that the artificial viscosity coefficient is in inverse proportion to power law of the rate of effective plas- tic strain,it is obtained that stress and strain both possess power law singularity and the singularity exponent is uniquely determined by the power law exponent of the rate of effective plastic strain. Variations of zoning structure as well as characteristics of stress and strain field at crack tip according to each material parameter are discussed by means of numerical computation for mode Ⅱ quasi-statically propagating crack, which show that the crack tip field is dominated by viscosity and plasticity of material at the same time. The crack tip field approaches to the corresponding HR field when the hardening coefficient is equal to zero.

关 键 词：准静态扩展 蠕变硬化材料 II型裂纹 裂纹尖端场 

分 类 号：O346.1[理学—固体力学] TB301[理学—力学]