VISCOPLASTIC SOLUTION TO FIELD AT STEADILY PROPAGATING CRACK TIP IN LINEARHARDENING MATERIALS  

作　　者：贾斌 王振清 李永东 梁文彦 

机构地区：[1]School of Astronautics Harbin Institute of Technology,Harbin 150001,P. R. China [2]Architectural Engineering College Harbin Engineering University,Harbin 150001,P. R. China [3]Mechanical Engineering Department Armored Forces Engineering Institute,Beijing 100072,P. R. China

出　　处：《Applied Mathematics and Mechanics(English Edition)》2006年第4期527-533,共7页应用数学和力学（英文版）

基　　金：Project supported by the Doctor Science Research Startup Foundation of Harbin Institute of Technology (No.01502485)

摘　　要：An elastic-viscoplastic constitutive model was adopted to analyze asymptotically the tip-field of moving crack in linear-hardening materials under plane strain condition. Under the assumption that the artificial viscosity coefficient was in inverse proportion to power law of the rate of effective plastic 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 according to each material parameter were discussed by means of numerical computation for the tip-field of mode II dynamic propagating crack, which show that the structure of crack tip field is dominated by hardening coefficient rather than viscosity coefficient. The secondary plastic zone can be ignored for weak hardening materials while the secondary plastic zone and the secondary elastic zone both have important influence on crack tip field for strong hardening materials. The dynamic solution approaches to the corresponding quasi-static solution when the crack moving speed goes to zero, and further approaches to the HR （Hui-Riedel） solution when the hardening coefficient is equal to zero.An elastic-viscoplastic constitutive model was adopted to analyze asymptotically the tip-field of moving crack in linear-hardening materials under plane strain condition. Under the assumption that the artificial viscosity coefficient was in inverse proportion to power law of the rate of effective plastic 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 according to each material parameter were discussed by means of numerical computation for the tip-field of mode II dynamic propagating crack, which show that the structure of crack tip field is dominated by hardening coefficient rather than viscosity coefficient. The secondary plastic zone can be ignored for weak hardening materials while the secondary plastic zone and the secondary elastic zone both have important influence on crack tip field for strong hardening materials. The dynamic solution approaches to the corresponding quasi-static solution when the crack moving speed goes to zero, and further approaches to the HR （Hui-Riedel） solution when the hardening coefficient is equal to zero.

关 键 词：quasi-static propagation dynamic propagation linear-hardening materials elastic-viscoplastic materials crack-tip field 

分 类 号：O346.1[理学—固体力学]