The Boom Fatigue Analysis Of The Heavy Duty Crawler Crane

Because of the high operating frequency and large load, fatigue damages would becaused in the heavy-duty crawler crane. In order to meet several working conditions andrequirements, all cranes (including the heavy-duty crawler crane) always trend to makethe crane smaller size, lighter weight and longer life. The heavy-duty crawler crane ismade up with lots of parts, and the boom is one of most typical and importantcomponents. It is one way to improve the fatigue strength of the boom while using thehigh strength material, which can extend both the lives of the boom and the crawler crane.This paper describes the necessary of boom fatigue analysis of the heavy-duty crawlercrane. And the domestic and foreign fatigue theories, calculation methods, the status of thefatigue analysis are introduced. This paper indicates three methods for stress analysis: basedon the theoretical formula of the stress analysis, finite element analysis and the actual stresstest. And according to the analysis made in this paper, it is obtained that finite elementanalysis and actual stress test as the basis for the force analysis.The focus of this paper is using axial load fatigue tests, as well as rotating and bendingfatigue tests on HSM770 high strength steel made in China; and the experimental resultsindicates the curves of p-S-N and S-N at two different loads. The results also show thatfatigue limits at different loads and the fatigue life of survival rate of 50% and 90% atcomputing 95% confidence level. This work fills the blank of fatigue analysis in this field,and could provide the related references for the other researchers.Finally, this paper proposes the steps of the boom's fatigue analysis. After testing the fatigue stress in one of the typical loading force point, a reasonable fatigue analysis methodis proposed based on theories and experiments.