Layered-Slipping Model For Bending Stress Analysis Of Stay Cables

The failure caused by bending behavior of stay cables have been paid more attention recently all over the world. A series of researches have been done which found that the bending stress at the anchor portion is the principal factor lead to failure of the stay cables. However, the shortage of analytic method of bending stress and the higher requirement for stay cables caused by the increasement of span make the research on behavior of stay cables more and more important.In order to analyze the bending fatigue of stay cables, a mechanical model should be proposed firstly. In this thesis, a method for bending stress of stay cables has been proposed, in which the layered-slipping was considered. A finite element model has been built with ANSYS. Based on the Sutong Bridge, the process of delamiation has been simulated, and the change of bending stress been attained also. The main objectives in this thesis are:1. The research on bending behavior of stay cables have been in-depth investigated. The effection of bending stress to fatigue behavior of stay cables has been recognized by comparing the the work of each country all over the world. The concept of layered-slipping for the analysis of bending stress have been proposed after introducing the character and the bound of each theory.2. The theory of bending for stay cables has been researched. A layered-slipping model has been proposed for the anlysis of bending stress. The model has been simplified after understanding the characters of bending state. The mechanical problem of layered-slipping has been translated into finite problem through the parameter design both for model and for controlling. The finite element model supplies a foundational method for bending stress analysis of stay cables.3. The parameterized model has been built with Ansys. The model of stay cable has been built with nonlinearal beam element. Meanwhile, the connection and slipping between each layer have been simulated by changing the condition of couple on the control node.4. An anslysis has been made on bending stress for practical stay cable. Based on Sutong Bridge, the process of delamiation has been simulated, and the change of bending stress has been attained. The differents between the solutions attained by layered-slipping model and the theory of uniform bending stiff have been discussed. Based on the results, the rationality of the layered-slipping model and method proposed in this thesis has been proved.All the work and results in this thesis have positive effects to the further research on bending fatigue of stay cables.