To determine the ultimate bearing capacity of foundations on sloping ground surface in practice, energy dissipation method was used to formulate the beating capacity as programming problem, and full-scale model experi...To determine the ultimate bearing capacity of foundations on sloping ground surface in practice, energy dissipation method was used to formulate the beating capacity as programming problem, and full-scale model experiments were investigated to analyze the performance of the soil slopes loaded by a strip footing in laboratory. The soil failure is governed by a linear Mohr-Coulomb yield criterion, and soil deformation follows an associated flow rule. Based on the energy dissipation method of plastic mechanics, a multi-wedge translational failure mechanism was employed to obtain the three bearing capacity factors related to cohesion, equivalent surcharge load and the unit gravity for various slope inclination angles. Numerical results were compared with those of the published solutions using finite element method and those of model experiments. The bearing capacity factors were presented in the form of design charts for practical use in engineering. The results show that limit analysis solutions approximate to those of model tests, and that the energy dissipation method is effective to estimate bearing capacity of soil slope.展开更多
In this paper, the configuration and working mechanism of the recently developed double spherical seismic isolation （DSSI） bearing are introduced in detail. Then, vertical displacement of the DSSI bearing due to sli...In this paper, the configuration and working mechanism of the recently developed double spherical seismic isolation （DSSI） bearing are introduced in detail. Then, vertical displacement of the DSSI bearing due to sliding on a spherical surface is analyzed. The results from seismic performance testing of the bearing are given, and a numerical analysis of a four span continuous girder bridge is performed. The numerical analysis compares the influence of three different bearing arrangement schemes on the structural seismic response, and the results show that the DSSI bearing is effective in increasing the vertical load bearing capacity, reducing the vertical displacement, and controlling the energy dissipation capacity within a certain range.展开更多
A elastic-plastic fatigue crack growth(FCG)finite element model was developed for predicting crack growth rate under cyclic load.The propagation criterion for this model was established based on plastically dissipated...A elastic-plastic fatigue crack growth(FCG)finite element model was developed for predicting crack growth rate under cyclic load.The propagation criterion for this model was established based on plastically dissipated energy.The crack growth simulation under cyclic computation was implemented through the ABAQUS scripting interface.The predictions of this model are in good agreement with the results of crack propagation experiment of compact tension specimen made of 304 stainless steel.Based on the proposed model,the single peak overload retardation effect of elastic-plastic fatigue crack was analyzed.The results shows that the single peak overload will reduce the accumulation rate of plastic energy dissipation of elements at crack tip plastic zone,so that crack growth will be arrested.The crack growth rate will not recover until the crack tip exceed the affected region.Meanwhile,the crack growth rate is mainly determined by the amplitude rather than the mean load under the condition of small scale yielding.The proposed model would be helpful for predicting the growth rate of mode I elastic-plastic fatigue crack.展开更多
基金Project(50408020) supported by the National Natural Science Foundation of Chinaproject(05-0686) supported by the Program of New Century Excellent Talents in Universityproject(200550) supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China
文摘To determine the ultimate bearing capacity of foundations on sloping ground surface in practice, energy dissipation method was used to formulate the beating capacity as programming problem, and full-scale model experiments were investigated to analyze the performance of the soil slopes loaded by a strip footing in laboratory. The soil failure is governed by a linear Mohr-Coulomb yield criterion, and soil deformation follows an associated flow rule. Based on the energy dissipation method of plastic mechanics, a multi-wedge translational failure mechanism was employed to obtain the three bearing capacity factors related to cohesion, equivalent surcharge load and the unit gravity for various slope inclination angles. Numerical results were compared with those of the published solutions using finite element method and those of model experiments. The bearing capacity factors were presented in the form of design charts for practical use in engineering. The results show that limit analysis solutions approximate to those of model tests, and that the energy dissipation method is effective to estimate bearing capacity of soil slope.
基金Supported by:National Nature Science Foundation of China Under Grant No.50708074
文摘In this paper, the configuration and working mechanism of the recently developed double spherical seismic isolation （DSSI） bearing are introduced in detail. Then, vertical displacement of the DSSI bearing due to sliding on a spherical surface is analyzed. The results from seismic performance testing of the bearing are given, and a numerical analysis of a four span continuous girder bridge is performed. The numerical analysis compares the influence of three different bearing arrangement schemes on the structural seismic response, and the results show that the DSSI bearing is effective in increasing the vertical load bearing capacity, reducing the vertical displacement, and controlling the energy dissipation capacity within a certain range.
基金Project No.51575076 supported by the National Natural Science Foundation of China.
文摘A elastic-plastic fatigue crack growth(FCG)finite element model was developed for predicting crack growth rate under cyclic load.The propagation criterion for this model was established based on plastically dissipated energy.The crack growth simulation under cyclic computation was implemented through the ABAQUS scripting interface.The predictions of this model are in good agreement with the results of crack propagation experiment of compact tension specimen made of 304 stainless steel.Based on the proposed model,the single peak overload retardation effect of elastic-plastic fatigue crack was analyzed.The results shows that the single peak overload will reduce the accumulation rate of plastic energy dissipation of elements at crack tip plastic zone,so that crack growth will be arrested.The crack growth rate will not recover until the crack tip exceed the affected region.Meanwhile,the crack growth rate is mainly determined by the amplitude rather than the mean load under the condition of small scale yielding.The proposed model would be helpful for predicting the growth rate of mode I elastic-plastic fatigue crack.
