| Flat-top Tower Crane’s advantage is more and more obvious in installation andservice condition, as the shortage development, so there is no enough data to checkworking load how to influence the structure. At present, the method of structurestrength and stability design calculation is used to research Flat-top Tower Crane, butseldom use the fatigue property analysis to consider the structure life with manyuncertain factors, such as load, material, and welding structure.This paper use QTZ100Flat-top Tower Crane hoist boom as the research object,obtain the fatigue life and allowed initial crack length of the welding place of hoistboom’s chord and web member,which utilize the finite element method andtheoretical approach,and experimental verification.The content of this paper is as follows:(1) Through theory and simulation to calculate welding place of hoist boom’schord and web member for the QTZ100Flat-top Tower Crane, and obtainthe stress of the welding place. Stress amplitude calculation method isgiven through research the tower crane’s load spectrum.(2) According to the stress amplitude and combining with <Crane DesignSpecification>（GB/T3811-2008）of the requirements for design life obtainallowed initial crack length with classic fatigue theory and high cyclefatigue damage theory.(3) Made fatigue tensile samples in a covering simplified for hoist boomwelding structure of the QTZ100Flat-top Tower Crane, conduct fatigueproperties experiment on the fatigue test machine and analyse theexperimental results.(4) Modeling and analysis the hoist boom welding structure for the QTZ100Flat-top Tower Crane with FEM, compare the stress and strain field withtheory and experiment results of crack propagation.The article emphatically from the welding structure of crack propagationmorphology and life, have the fatigue life and allowed initial crack length of thewelding structure,which provides a new approach for fatigue life design, andprovides the theory basis to calculate fatigue life for tower crane. |
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