Study Of Fatigue and Crack Analysis In Welded Components through FEA

Abstract

With the increasing importance being given to the machines for carrying out the earth moving task the need for carrying out proper designing and finite element analysis of such earth moving equipments is increasing by leaps and bounds. As these are heavy duty equipments and many different kind of weld are here to dominate the strength of overall structure, it become utmost necessary to carry out various calculations for the life estimation .More over in this era of globalization and cut throat competition it is sufficient that the machine should perform satisfactory but also it is very important to carry out analysis to reduce the chances of failure. The model given was of an excavator’s arm, is generated by using CAD software CATIA V5, which is used as the input for the finite element analysis. Solid model once generated can be used to carry out finite element analysis on it. Analysis procedure consists of the following tasks to obtain the final results of static analysis which is used as input for fatigue and crack analysis. 1. Meshing the model using suitable elements. 2. Assigning the material properties to the meshed model. 3. Applying the boundary constraints. 4. Applying loads on the model. 5. Post processing of the results to view the solution. Various stress plots and displacement plots are obtained as results.The software used to carryout the analysis is HyperMesh 8.0. For post processing of the results ABAQUS 6.8.3 and IDEAS 9 is used. For calculation of fatigue life two approaches viz. Stress-life and LEFM were used. Three different stresses values were taken far the stress-life approach for life estimation. The best method is justified. For crack analysis the results of stress analysis were taken as input and the at the weld interface zone various load calculation and size evaluation were performed manually. Later the life is estimated using suitable method through LEFM.