Development Of Fatigue Life Analysis Network Platform Based On The Theory Of Damage Tolerance

Fatigue rupture is one of the main failure modes of mechanical parts.It is important to study the mechanism of fatigue crack growth and predict the fatigue life for the design and safety evaluation of parts.In order to solve the problem of complex fatigue life calculation model,large calculation amount and low efficiency,this paper establishes a fatigue crack life analysis network platform which combining the knowledge of fatigue crack propagation analysis theory and the technology of computer network.The fatigue analysis platform stores material parameters through a database,and completes complex calculations and analysis through a computer.The fatigue analysis platform enables researchers to avoid duplication of labor and greatly improve the efficiency of scientific research.Firstly,this paper studies the prediction method of estimating the fatigue crack growth life of parts under constant amplitude load based on the theory of damage tolerance,and establishes the calculation library of stress intensity factor of conventional crack.This paper combined with counting method,load spectrum theory,cumulative damage theory and overload hysteresis effect to calculate crack extension life under variable amplitude conditions.This paper also studied the fatigue crack propagation mechanism of common welded joints,and the calculation method of the stress intensity factor of the weld toe,the root of the weld,the local penetration crack,and the through crack.The extended life of the weld crack is estimated by the welding fatigue crack growth rate model.Secondly,the browser/server structure is chosen as the platform design mode according to the concept of modern networked mechanical design.The basic operation frameworks of Spring,SpringMVC and Mybatis(SSM)are determined.The technical architecture of the fatigue life analysis platform was completed based on the J2 EE platform.The overall design of the fatigue analysis platform was completed from the functional requirements of fatigue life calculation of components.The fatigue analysis platform is mainly composed of the operation interface for human-computer interaction,the database for storing material parameters and the program for estimating fatigue life.Finally,the fatigue crack propagation life calculation model is programmed by using the object-oriented programming language Java.The PostgreSQL database is used to store the material parameters and calculation results.The operation interface of the analysis platform was designed by using BootStrap framework and JavaScript technology.The accuracy and efficiency of the platform are verified by fatigue life examples.The results show that the platform can calculate the extended life of common cracks under constant amplitude load and variable amplitude loads efficiently,which greatly saves computational cost and time.