Experimental and numerical evaluation of cumulative fatigue damage of welded structure

Abstract

Frequent crack occurrence in welded components after operation in different condition of rotor excavator bearing structures is observed during service. Program of the analysis of these cracks included the identification of critical regions, measuring strains in these regions by strain gauges in different conditions, determination of stress spectrum based on performed measurements, production of model corresponding to selected welded joint from real structure and model testing by variable load of constant amplitude and by defined stress spectrum. Obtained experimental results are compared to numerical solutions, applying linear fatigue damage accumulation hypothesis by Palmgren-Miner /1, 2/, and by modified linear hypothesis, trying to correct its system errors, proposed by Corten-Dolan /3/, Serensen- Kogaev /4/ and Haibach /5/.