Study Of Fatigue Performance On The Shear Pin Of High-Speed Railway Space Rigid Frame

High speed railway bridge and existing bridges under the action of stress compared with the train speed, high operating frequency, etc., these will bring a series of problems of bridge fatigue. Among them, train speed is high, leading to the bridge impact condition complex, will increase the overall component or the local details of the high stress amplitude; train operation number increase, cause component stress cycle number increase; these are on the bridge structure fatigue adverse. A high speed railway space frame structure shear pin parts of complex structure, stress distribution. In the constant load and live load under the action of shear pin, and the circumferential weld will withstand high amplitude of cyclic stress, the strength and fatigue problem should cause height to take seriously. In order to ensure the bridge operation quality and safety, the shear pin and the circumferential weld fatigue performance study and evaluation are very important.First of all, this paper introduces the construction of high speed railway and rigid frame bridge, described the system fatigue research sequence of events, the related theory and anti fatigue design in general, and a brief description for a high-speed railway space rigid frame structure shear pin of the research content and research method.Secondly, the shear pin detail model establishment, in order to accurately simulate the mechanical properties of the pin shaft connection, the pin shaft and the ear plate between the contact nonlinear analysis, accurately reflect the practical condition of the structure. Using the finite element software ANSYS on shear pin actuating mechanism, stress distribution, stress concentration phenomenon undertakes an analysis, to draw some useful conclusions validate structure rule and, at the same time the rationality and security of.Again, based on the actual bridge shear pin, using rain flow method to establish the fatigue test load spectrum, fatigue testing scheme and testing options, while the model of fatigue loading after a certain number of static load test, test the stress difference, stress distribution, displacement and model no residual deformation, in addition to the fatigue loading end, also on the model of the flaw detection, thereby testing structure after fatigue test damage, at the same time, with the results of finite element calculation, comparison and analysis of mutual check, test results.Then, the finite element analysis and fatigue test on the basis of the results, draw lessons from domestic and international relevant standards, with all relevant specification validation to evaluate the fatigue performance of the shear pin.Finally, using the theory of reliability, the limit state equation is introduced to build, the first order two moment method and its numerical iterative method. A large number of references, identifies all the statistical parameters of random variable. Based on the curve of fatigue life reliability theory and based on the linear elastic fracture mechanics the fatigue life reliability theory two aspects to evaluate the fatigue performance of the shear pin.