In order to study the fatigue properties of rib-to-deck welded connection and rib-to-rib welded connection in orthotropic steel bridge decks,a multi-scale finite element model was set up to analyze the stress distribu...In order to study the fatigue properties of rib-to-deck welded connection and rib-to-rib welded connection in orthotropic steel bridge decks,a multi-scale finite element model was set up to analyze the stress distribution characteristics and the load test was conducted on the Taizhou Yangtze River Bridge.Comparing the vehicle test results with the muli-scale finite element model results to verify the accuracy of the finite element simulation for the stress response of two welded details.The results indicated that The stress at the rib-to-deck welded connection and the rib-to-rib welded connection are the bending stress and the membrane stress,respectively;the stress response of the two welded connection has strong local characteristics;the lateral stress influence line of the two welded connection is relatively short and the length of the lateral stress influence line is greatly affected by the longitudinal ribs;increasing the thickness of the roof and longitudinal ribs can reduce the stress response and improve the stress performance of the heavy lanes.For the two welded details,the fatigue damage increment of the ordinary lane is greater than the heavy lane.The thickened roof and longitudinal ribs at the position of the heavy lane still cannot balance the fatigue damage caused by the heavy truck.Therefore,it is necessary to strictly control the fatigue effect of overloaded vehicles on steel box girders.展开更多
Due to the complex structure and dense weld of the orthotropic steel bridge deck(OSBD),fatigue cracks are prone to occur in the typical welding details.Welding residual stress(WRS)will cause a plastic zone at the crac...Due to the complex structure and dense weld of the orthotropic steel bridge deck(OSBD),fatigue cracks are prone to occur in the typical welding details.Welding residual stress(WRS)will cause a plastic zone at the crack tip.In this paper,an elastoplastic constitutive model based on the Chaboche kinematic hardening model was introduced,and the extended finite element method(XFEM)was used to study the influence of material elastoplasticity and crack tip plastic zone on the law of fatigue crack propagation.By judging the stress state of the residual stress field at the crack tip and selecting different crack propagation rate models to investigate the crack propagation law when plastic deformation was considered,the propagation path and propagation rate of fatigue crack of the OSBD were obtained.The results show that,whether the residual stress field is considered or not,the plastic deformation at the crack tip will not cause the obvious closure of the fatigue crack at the U-rib toe during the crack propagation process,but will significantly affect the crack propagation path.When material plasticity is considered,the propagation angle of fatigue crack at the U-rib toe basically remains unchanged along the short-axis direction of the initial crack,but is going up along the long-axis direction,and the crack tip plastic zone inhibits the propagation of the crack tip on one side.Compared with linear elastic materials,the crack propagation law considering material plasticity is more consistent with that in actual bridge engineering.In terms of the propagation rate,if the residual stress field is not considered,the fatigue crack propagation rate at U-rib toe with plasticity considered is slightly higher than that without plasticity considered,because plastic deformation will affect the amplitude of energy release rate.When considering the WRS field,the fatigue crack propagation rate at U-rib toe is increased due to the combined actions of plastic deformation and stress ratio R.展开更多
To study the fatigue performance of welded details in the orthotropic steel decks,the steel box girder for Taizhou Yangtze River Bridge is taken as the research object.Based on the field monitoring data obtained from ...To study the fatigue performance of welded details in the orthotropic steel decks,the steel box girder for Taizhou Yangtze River Bridge is taken as the research object.Based on the field monitoring data obtained from the load test,the stress response test of the orthotropic steel box girder under wheel loads is performed and the correctness of the vehicle test data obtained from the field monitoring data also have been verified by the numerical results of the finite element model.Based on the Miner linear cumulative damage theory,the S-N curve of the Eurocode3 specification is referenced,and the fatigue life calculation formula of the welded details is determined according to the actual structural features.The fatigue life evaluation of the four typical welded details is obtained.The results indicate that:The load test data is compared and verified by the numerical result of finite element model.The local effect of stress distribution is remarkable.The stress measurement points on the four typical welded details are mainly based on low amplitude stress cycles.Most of the stress ranges are 2-10 MPa,among which the stress range of the welded details at the U-rib butt joint is larger.The fatigue life of welded details in the 14 mm thick top plate is smaller than that of the 16 mm thick top plate corresponding to the fatigue life of the welded details.The rib-to-rib butt welded joints and the openings of the diaphragms were prone to fatigue failure.Among them,the welding details of the 14 mm thick U-rib butt joints first appeared fatigue failure.The arrangement of the diaphragm can effectively increase the fatigue life of the top-U rib weld and improve the fatigue performance at this detail.展开更多
基金This research has been supported by the National Natural Science Foundation of China(Grant No.51778135)the National Key R&D Program Foundation of China(Grant No.2017YFC0806001)+2 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20160207)Aeronautical Science Foundation of China(Grant No.20130969010)the Fundamental Research Funds for the Central Universities and Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant Nos.KYCX18_0113 and KYLX16_0253).
文摘In order to study the fatigue properties of rib-to-deck welded connection and rib-to-rib welded connection in orthotropic steel bridge decks,a multi-scale finite element model was set up to analyze the stress distribution characteristics and the load test was conducted on the Taizhou Yangtze River Bridge.Comparing the vehicle test results with the muli-scale finite element model results to verify the accuracy of the finite element simulation for the stress response of two welded details.The results indicated that The stress at the rib-to-deck welded connection and the rib-to-rib welded connection are the bending stress and the membrane stress,respectively;the stress response of the two welded connection has strong local characteristics;the lateral stress influence line of the two welded connection is relatively short and the length of the lateral stress influence line is greatly affected by the longitudinal ribs;increasing the thickness of the roof and longitudinal ribs can reduce the stress response and improve the stress performance of the heavy lanes.For the two welded details,the fatigue damage increment of the ordinary lane is greater than the heavy lane.The thickened roof and longitudinal ribs at the position of the heavy lane still cannot balance the fatigue damage caused by the heavy truck.Therefore,it is necessary to strictly control the fatigue effect of overloaded vehicles on steel box girders.
基金The works described in this paper are substantially supported by the grant from the National Natural Science Foundation of China(Grant No.51678135)the Natural Science Foundation of Jiangsu Province(No.BK20171350)Six Talent Peak Projects in Jiangsu Province(JNHB-007),which are gratefully acknowledged.
文摘Due to the complex structure and dense weld of the orthotropic steel bridge deck(OSBD),fatigue cracks are prone to occur in the typical welding details.Welding residual stress(WRS)will cause a plastic zone at the crack tip.In this paper,an elastoplastic constitutive model based on the Chaboche kinematic hardening model was introduced,and the extended finite element method(XFEM)was used to study the influence of material elastoplasticity and crack tip plastic zone on the law of fatigue crack propagation.By judging the stress state of the residual stress field at the crack tip and selecting different crack propagation rate models to investigate the crack propagation law when plastic deformation was considered,the propagation path and propagation rate of fatigue crack of the OSBD were obtained.The results show that,whether the residual stress field is considered or not,the plastic deformation at the crack tip will not cause the obvious closure of the fatigue crack at the U-rib toe during the crack propagation process,but will significantly affect the crack propagation path.When material plasticity is considered,the propagation angle of fatigue crack at the U-rib toe basically remains unchanged along the short-axis direction of the initial crack,but is going up along the long-axis direction,and the crack tip plastic zone inhibits the propagation of the crack tip on one side.Compared with linear elastic materials,the crack propagation law considering material plasticity is more consistent with that in actual bridge engineering.In terms of the propagation rate,if the residual stress field is not considered,the fatigue crack propagation rate at U-rib toe with plasticity considered is slightly higher than that without plasticity considered,because plastic deformation will affect the amplitude of energy release rate.When considering the WRS field,the fatigue crack propagation rate at U-rib toe is increased due to the combined actions of plastic deformation and stress ratio R.
基金This study was financially supported by the National Natural Science Foundation,China(51778135)the Natural Science Foundation of Jiangsu Province,China(BK20160207)+3 种基金Aeronautical Science Foundation,China(20130969010)the Fundamental Research Funds for the Central Universities and Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX18_0113KYLX16_0253)the National Key Research and Development Program of China(2017YFC0806001).
文摘To study the fatigue performance of welded details in the orthotropic steel decks,the steel box girder for Taizhou Yangtze River Bridge is taken as the research object.Based on the field monitoring data obtained from the load test,the stress response test of the orthotropic steel box girder under wheel loads is performed and the correctness of the vehicle test data obtained from the field monitoring data also have been verified by the numerical results of the finite element model.Based on the Miner linear cumulative damage theory,the S-N curve of the Eurocode3 specification is referenced,and the fatigue life calculation formula of the welded details is determined according to the actual structural features.The fatigue life evaluation of the four typical welded details is obtained.The results indicate that:The load test data is compared and verified by the numerical result of finite element model.The local effect of stress distribution is remarkable.The stress measurement points on the four typical welded details are mainly based on low amplitude stress cycles.Most of the stress ranges are 2-10 MPa,among which the stress range of the welded details at the U-rib butt joint is larger.The fatigue life of welded details in the 14 mm thick top plate is smaller than that of the 16 mm thick top plate corresponding to the fatigue life of the welded details.The rib-to-rib butt welded joints and the openings of the diaphragms were prone to fatigue failure.Among them,the welding details of the 14 mm thick U-rib butt joints first appeared fatigue failure.The arrangement of the diaphragm can effectively increase the fatigue life of the top-U rib weld and improve the fatigue performance at this detail.
基金National Key R&D Program of China(No.2021YFE0107800)National Science Foundation for Distinguished Young Scholars(No.52325805)CCCC Academician Special Scientific Research Funding Project(No.YSZX-03-2021-01-B).
