CAJ | 학술논문

文章提出了基于最大裂纹张口位移计算Ⅰ型应力强度因子的新方法,该方法适用于复合载荷(均匀拉伸和纯弯曲载荷组合)作用下的具有半椭圆表面裂纹的有限平板模型.首先,理论推导了具有埋藏裂纹的无限大平板受均匀拉伸载荷作用时应力强度因子与裂纹最大张口位移的对应关系,再应用有限元数值模拟技术,考虑了表面效应、模型尺寸效应及载荷形式的影响,然后基于有限元模拟结果,根据多元多次最小二乘法原理拟合出对应修正系数表达式,最终建立了复合载荷作用下有限平板裂纹尖端应力强度因子与最大张口位移的函数关系,实现了由容易获得的最大裂纹张口位移确定应力强度因子的方法.该方法避免了对裂纹尖端的应力场、位移场的分析,为实际应用中应力强度因子的获得提供了新的方法.
문장제출료기우최대렬문장구위이계산Ⅰ형응력강도인자적신방법,해방법괄용우복합재하(균균랍신화순만곡재하조합)작용하적구유반타원표면렬문적유한평판모형.수선,이론추도료구유매장렬문적무한대평판수균균랍신재하작용시응력강도인자여렬문최대장구위이적대응관계,재응용유한원수치모의기술,고필료표면효응、모형척촌효응급재하형식적영향,연후기우유한원모의결과,근거다원다차최소이승법원리의합출대응수정계수표체식,최종건립료복합재하작용하유한평판렬문첨단응력강도인자여최대장구위이적함수관계,실현료유용역획득적최대렬문장구위이학정응력강도인자적방법.해방법피면료대렬문첨단적응력장、위이장적분석,위실제응용중응력강도인자적획득제공료신적방법.
In order to study a flat plate with semi-elliptical surface crack subjected to combined loading,a new method to calculate the mode I stress intensity factor (KI) based on the maximum crack opening displacement (MCOD) is presented.In this method,based on the embedded cracked plate under combined loading,the relationship between KI and MCOD is deduced by theory analysis.Finite element method is then employed to consider the influences of surface effect,model size effect and load form on the relationship.Series results of KI and MCOD are obtained,and some modified coefficients as functions of crack shapes and plate sizes are acquired by binary quadratic polynomial curve fitting approach.According to theoretical analysis and modified coefficients,the relationship between KI and MCOD is established.It is believed that the KI can be estimated by the MCOD of surface crack obtained easily.The proposed method avoids analyzing the fields of stress and displacement around crack tip,which provides a new approach to calculate stress intensity factor in practice.