Numerical Stress Analysis And Fatigue Assessment Of Wire Rope Hanger Of Railway Suspension Bridge

Suspension bridge is a kind of long span bridges. Suspender cable is the main connecting component of suspension bridge, it turns weaken easily on account of the influence of surrounding condition and temperature. During its operational life span, vehicle and wind load may bring out material fatigue easily. However there was rarely domestic research on stress and fatigue analysis of inner steel wire in wire rope sling of suspension bridge. The following issues aim at the above mentioned problems was mainly discussed in this thesis:1. Stress analysis of steel wires in wire ropeBased on the fundamental principle of force action of wire rope summarized by Costello, deduction for simple structure calculation formula of internal stress of steel wire rope has been got and related program has been programmed, the theory of internal stress of simple structure steel wire rope have been expanded to multilayer and multi-strand wire rope, make the stress analysis of the internal steel wire rope has more accurate quantitative results.2. Space geometric model and finite element model have been constructedMathematical equations of the center line of steel wire in wire rope in the state of vertical and bending have been got. According to the corresponding geometrical relationship in wire rope, geometrical space and finite element model have been established, and the problems that should be aware of when analyzing wire rope finite element model have been discussed. Theoretical calculation values were verified based on simple structure finite element model of wire rope.3. Fatigue strength of wire rope sling has been checked with the theoretical formulasLoading mode has been got according to Chinese railway bridge design specifications and standards about fatigue analysis, load value that the hunger bearing has been got by using the nonlinear analysis system for bridge structure BNLAS. Combined with the sling fatigue load value, the most unfavorable fatigue point at steel wire in the wire rope have been checked by using the theoretical formula that derived, fatigue strength of steel wire have been obtained and fatigue strength of steel wire rope have been checked according to the related theory.Through analysis and research of this thesis, concluded that:correct stress result of various structured wire rope can be got by the stress calculation formula derived in this thesis. The stress of center steel wire is the largest when the wire rope is subjected to bending moment, calculation of internal force of the external screw steel wire can be got by using the corresponding deformation conversion ratio coefficient. Overlap problem due to deformation of steel wires likely happens among steel wires when establishing finite element model, this problem can be solved by using the method of modeling mathematically. Fatigue problem of sling wire rope in the sling straddles cable clamp is outstanding, and that in the vertical line segment and the anchoring is slighter relatively.