CAJ | 학술논문

【目的】进一步探索材料裂纹扩展分叉的机理。【方法】采用晶体相场模型研究平面应力作用下材料裂纹扩展的动态演化过程，分析裂纹扩展过程体系自由能 G 、裂纹面积分数 S 、裂口周长 L 的变化特征；分别从 G、S、L的变化阐述裂纹扩展以及三者与裂纹扩展临界应变εc 的对应关系；探讨裂口扩展和主裂纹分叉与体系能量 G 的内在关联。【结果】无应力施加时期，裂纹面积分数 S 和裂口周长L 没有变化；施加拉伸应力后，当系统应变达到一定程度时，S 和 L 开始同时增加，此时的应变大小对应于裂纹启裂临界应变εc 值。【结论】应力施加导致材料中心裂口处应力集中，体系能量上升，系统能量曲线一阶导数的拐点对应于中心裂纹启裂时刻或临界应变。自由能曲线一阶导数拐点处能量上升速率变缓，表明此时弹性应变能得到释放。
【목적】진일보탐색재료렬문확전분차적궤리。【방법】채용정체상장모형연구평면응력작용하재료렬문확전적동태연화과정，분석렬문확전과정체계자유능 G 、렬문면적분수 S 、렬구주장 L 적변화특정；분별종 G、S、L적변화천술렬문확전이급삼자여렬문확전림계응변εc 적대응관계；탐토렬구확전화주렬문분차여체계능량 G 적내재관련。【결과】무응력시가시기，렬문면적분수 S 화렬구주장L 몰유변화；시가랍신응력후，당계통응변체도일정정도시，S 화 L 개시동시증가，차시적응변대소대응우렬문계렬림계응변εc 치。【결론】응력시가도치재료중심렬구처응력집중，체계능량상승，계통능량곡선일계도수적괴점대응우중심렬문계렬시각혹림계응변。자유능곡선일계도수괴점처능량상승속솔변완，표명차시탄성응변능득도석방。
[Objective]The dynamic process of crack propagation under the biaxial tensile deform-ation is simulated by using the phase-field-crystal model.[Methods]The variation characteris-tics of the factors,such as the free energy G,crack area fraction S,crack circumference L,on crack propagation were analyzed.The crack propagation dynamic process and the correspond-ing relation of the critical strain for crack propagation were illustrated based on the changes of G,S,L in crack propagation.Both the crack propagation and the main crack bifurcation were investigated with their relationship to system energy G.[Results]The crack area S scores and fissure perimeter L did not change without applying stress.When the strain of system reached a certain extent,S and L began to increase at the same time.At this point the strain magnitude corresponds to the crack critical strainεc .[Conclusion]Application of stress to the center of the crack induces the stress concentration.The inflection point of first derivative for the free energy curve is corresponding to the crack propagation time.The first derivative of the free energy curve can be slowed down at the inflection point,which indicates that the elastic strain energy can be released at this time.