Crack Initiation And Propagation Under The Condition Of Equal Displacement Using Phase Field Crystal Method

With the development of science and technology,all kinds of new materials are constantly emerging,the attention people pay on the material properties and safety is gradually improving.With the understanding of material failure deeply,the theory of crack propagation have been developed and perfected,which provides the basis of the practical application of materials.Some mature material detection methods which can use to test materials in service are gradually formed.With the rapid development of the computer,the numerical calculation has been gradually applied by researchers in the study of crack,which can greatly reduce the test cost,and provide more accurate theoretical support.The phase field crystal method(PFC)can be carried out from the theoretical research of atomic diffusion time scale and spatial scale changes on the structure of the material.At present,the research on the crack initiation and propagation evolution of internal micro structures has been developed rapidly.However,as a new numerical simulation method,the related researches in this field are rarely reported.In this paper,under the condition of equal displacement,the critical dimension of crack initiation is studied.The effects of different parameters of temperature,orientation angle and liquid phase on crack propagation were analyzed with the curve of free energy.The main results of this study are as follows:1.Under the condition of equal displacement strain,crack initiation is closely related to the initial notch size which vertical the direction of strain.When the size,which vertical the direction of strain,only reach the critical value,the sample will crack.With the increase of temperature,the critical size will be reduced accordingly.2.The initial notch size,which is parallel to the direction of strain,has a certain effect on the crack initiation time,and with the increase of the size,the crack initiation time will be delayed.Meanwhile,with the increase of temperature,hysteresis phenomenon will be significantly weakened.3.The crack initiation mechanism is the same with the increase of the liquid phase parameters,but the process of crack initiation and propagation will be accelerated.4.The crack initiation is closely related to the size of the orientation angle.Different orientation angles correspond to different crack initiation mechanism,But the overall crack initiation and propagation process contains vacancy formation and cleavage of two kinds of mechanism,and relative to the cleavage mechanism,the formation mechanism of vacancy can consume more energy.