J₂ Conservation Law And Its Application In Structural Stress Intensity Factor Calculation

Affected by various factors such as processing and manufacturing,use conditions,various defects will inevitably remain in the engineering structure or equipment,and various defects will also occur during service.Under the action of load,these defects will evolve into cracks or crack-like defects,posing a threat to the production safety of structures and equipment.As an important parameter in fracture theory,stress intensity factor plays an core physical parameter in structural integrity evaluation,reliability evaluation and remaining life analysis.A simple and effective method for solving stress intensity factors is of great significance to fracture theory and engineering applications.Paper conservation law theory,proposed a method for calculating stress intensity factor profiled plates and shells Solving.The calculation of stress intensity factors of irregular thin-walled plate members with periodic cracks is studied.Firstly,this paper studies the characteristics of conservation law integrals in three-dimensional and plane problems,and analyzes the law of its application in solving stress intensity factors.These laws are the theoretical source of using conservation integrals to establish the method of solving the stress intensity factors of cracked structures.The core and key problem of using conservation law to solve the stress intensity factor is how to rationally design the integration loop according to the specific research object's structural characteristics,load characteristics,and the calculation characteristics of the conservation law.In this paper,by selecting the integral path of the K-control zone,the stress intensity factor is successfully introduced into the conservation integral and transformed into an equation for solving the stress intensity factor.The establishment of this equation shows the status and role of the J₂-integral in the conservation law in the method of solving the stress intensity factor.Secondly,the problem of solving the stress intensity factor of the thin-walled stiffened plate with periodic cracks in various configurations is deeply studied.Although the thin-walled stiffened plate configuration is a typical three-dimensional finite boundary crack problem,it can still be combined with the characteristics of the far-field cross-sectional stress distribution,the plane strain characteristics of the crack tip K-control zone,and the large-area free surface of the plate and shell structure.To create a stress intensity factor calculation method based on conservation integration.Finally,the stress intensity factor solution of the periodic crack of the thin-walled stiffened plate under the bending load obtained by the established stress intensity factor solution method is compared with the finite element numerical solution.The results show that the cross-sectional stress calculated by the elementary material mechanics method.The errors introduced by the site are acceptable in engineering applications.It further shows that the technical route for solving the stress intensity factor established in this paper is feasible,especially for solving the stress intensity factor of a three-dimensional complex crack structure,and the calculation process is very simple and flexible,and a closed solution can be obtained.