Publisher : The Korean Welding and Joining Society
DOI : 10.5781/JWJ.2015.33.6.49
Title & Authors
Fatigue Life Prediction of Non-Load-Carrying Cruciform Welded Joint using Master S-N Curve based on Structural Stress Approach Kwak, Si-Young;
Welding process is of importance to assemble products or structures, but also the process is structural weakness due to stress concentration in welding joint. The fatigue design of welded joint requires time & labor consuming fatigue test because the fatigue life is various according to the depth of joint, joint type and load type etc. In fatigue design codes, they guide to classify welding joints with their shape( BS7608, IIW Documents) and provide fatigue assessment information. In terms of numerical method for fatigue analysis, it is also difficult to decide the stress peak in joint because of mesh sensitivity which means that stress value is varies with element type or size on stress concentration zone. Hot-spot method is used generally, but Battelle of United States proposed Master S-N Curve based on structural stresses converted by mechanical equilibrium theory. In this research, we extracted master S-N curve from Battelle's fatigue test DB including test data of various welding joints to apply on Non-Load-Carrying cruciform Joint. Comparing fatigue results between the case of using normal stress and case of structural stress cor the cruciform Joint, The suggested Battelle method showed successive results.
Jeongkyun Hong, Development and Application of the Battelle Structural Stress Method for Fatigue Evaluation of Welded Automotive Structures, Journal of KWJS, 30-2 (2012), 126-134 (in Korean)
Seongmin Kim, Youngnam Kim, Seunghyun Lee and Myunghyun Kim, Fatigue Assessment of Load-carrying Asymmetric Double Bevel Cruciform Welded Joints using Structural Stress Approach, Journal of KWJS, 30-6 (2012), 572-577 (in Korean)
Dongil Ryu et al., Master Fatigue Curve of SS400 Material through Equivalent Structural Stress, Journal of KSME, 38-4 (2014), 287-288 (in Korean)
Chulsu Kim et al., Fatigue Analysis of Welding Bogie Frames for Rolling Stocks Using The equilibrium-equivalent structural stress method, The Korean Society for Railway Preceeding (2010.07), 1243-1248 (in Korean)
ASME, Boiler and Pressure Vessel Code, Section VIII, Div.2(2007)
MSC Nastran User Guide, chapter 4 Grid Point Force Balance Results, UNIVERSAL ANALYTICS, INC.
Program & User manual, Web site, http://www.jejoup. kr/db/processdb.aspx