Fatigue Life Prediction Of Bridge Crane Wire Rope

To predict the reliability of the bridge crane, the factors that influence thefatigue life of wire rope are discussed, and targeted measures are proposed. On theother hand, a quantitative study about the fatigue life is investigated, includingsoftware simulation, theoretical calculations and experimental research.The method of software simulation is given as follows. First, Solid Works isused to build the three-dimensional model of the wire rope. And then, static analysisis conducted to determine the weak points of stress and strain. Finally, the fatigueanalysis module is applied to estimate the fatigue life.Theoretical estimate of the fatigue life must be based on the stress-life curve ofwire rope material No.65steel. But so far, there is no related literature on stress-lifecurve of No.65steel. To achieve the theoretical prediction of the wire rope fatiguelife, test method is proposed to get the stress-strain relationship of No.65steel firstly.Then, the stress-life relationship is obtained by transforming combined with localstress-strain method. Therefore, it is possible to estimate the fatigue life of the wirerope.Compared fatigue life results between the wire rope model and wire rope-pulleymodel based on Nsoft approximate S-N curve with fatigue life results based on thetrue stress-true strain of No.65steel, the deviation are5.86%and47.8%. It isindicate that the feasibility of using the true stress-true strain curve to estimate thefatigue life of wire rope when strain fatigue occurs. The fatigue life of wire ropemodel and wire rope-pulley model are7683.8and2.9629×105lifting timesrespectively when the load is added from the free state10.26MPa to the rated load115.54MPa two load steps.