Traditional rigid body limit equilibrium method （RBLEM） was adopted for the stability evaluation and analysis of rock slope under earthquake scenario. It is not able to provide the real stress distribution of the st...Traditional rigid body limit equilibrium method （RBLEM） was adopted for the stability evaluation and analysis of rock slope under earthquake scenario. It is not able to provide the real stress distribution of the structure, while the strength reduction method relies on the arbitrary decision on the failure criteria. The dynamic limit equilibrium solution was proposed for the stability analysis of sliding block based on 3-D multi-grid method, by incorporating implicit stepping integration FEM. There are two independent meshes created in the analysis： One original 3-D FEM mesh is for the simulation of target structure and provides the stress time-history, while the other surface grid is for the simulation of sliding surface and could be selected and designed freely. As long as the stress time-history of the geotechnical structure under earthquake scenario is obtained based on 3-D nonlinear dynamic FEM analysis, the time-history of the force on sliding surface could be derived by projecting the stress time-history from 3-D FEM mesh to surface grid. After that, the safety factor time-history of the sliding block will be determined through applying limit equilibrium method. With those information in place, the structure＇s aseismatic stability ean be further studied. The above theory and method were also applied to the aseismatic stability analysis of Dagangshan arch dam＇s right bank high slope and compared with the the result generated by Quasi-static method. The comparative analysis reveals that the method not only raises the FEM＇s capability in accurate simulation of complicated geologic structure, but also increases the flexibility and comprehensiveness of limit equilibrium method. This method is reliable and recommended for further application in other real geotechnical engineering.展开更多
The main focus is nonlinear model-based dynamic positioning (DP) control system design. A nonlinear uniform global exponential stability (UGES) observer produces noise-free estimates of the position, the slowly varyin...The main focus is nonlinear model-based dynamic positioning (DP) control system design. A nonlinear uniform global exponential stability (UGES) observer produces noise-free estimates of the position, the slowly varying environmental disturbances and the velocity, which are used in a proportional-derivative (PD) + feedforward control law. The stability of this observer-controller system is proved by introducing a specific nonlinear cascaded system. The simulation results have successfully demonstrated the performance of designed DP control system.展开更多
为克服筒仓结构在地震易损性评估时需要进行大量非线性时程分析的不足,采用基于耐震时程法(endurance time method,ETM)的易损性分析方法对筒仓结构进行易损性的快速评估。以IV类场地柱承式筒仓为研究对象,选取实际天然地震动记录为目...为克服筒仓结构在地震易损性评估时需要进行大量非线性时程分析的不足,采用基于耐震时程法(endurance time method,ETM)的易损性分析方法对筒仓结构进行易损性的快速评估。以IV类场地柱承式筒仓为研究对象,选取实际天然地震动记录为目标反应谱合成3条耐震时程曲线,利用有限元软件ABAQUS建立柱承式筒仓模型并输入耐震时程曲线,将ETM分析结果与增量动力分析方法(incremental dynamic analysis,IDA)结果进行对比。结果表明:ETM分析结果与IDA分析结果的中位值相匹配,满足筒仓结构抗震性能分析精度要求;筒仓不同支承柱在地震作用下的基底剪力分配情况与储料质量无关,仅取决于支承柱位置;ETM所得的筒仓地震易损性曲线与IDA易损性曲线基本吻合,耐震时程法可作为柱承式筒仓抗震性能分析、预测和评估的高效方法。展开更多
基金Project(2013-KY-2) supported by the State Key Laboratory of Hydroscience and Engineering of Hydroscience, ChinaProject(50925931)supported by the National Funds for Distinguished Young Scientists, China
文摘Traditional rigid body limit equilibrium method （RBLEM） was adopted for the stability evaluation and analysis of rock slope under earthquake scenario. It is not able to provide the real stress distribution of the structure, while the strength reduction method relies on the arbitrary decision on the failure criteria. The dynamic limit equilibrium solution was proposed for the stability analysis of sliding block based on 3-D multi-grid method, by incorporating implicit stepping integration FEM. There are two independent meshes created in the analysis： One original 3-D FEM mesh is for the simulation of target structure and provides the stress time-history, while the other surface grid is for the simulation of sliding surface and could be selected and designed freely. As long as the stress time-history of the geotechnical structure under earthquake scenario is obtained based on 3-D nonlinear dynamic FEM analysis, the time-history of the force on sliding surface could be derived by projecting the stress time-history from 3-D FEM mesh to surface grid. After that, the safety factor time-history of the sliding block will be determined through applying limit equilibrium method. With those information in place, the structure＇s aseismatic stability ean be further studied. The above theory and method were also applied to the aseismatic stability analysis of Dagangshan arch dam＇s right bank high slope and compared with the the result generated by Quasi-static method. The comparative analysis reveals that the method not only raises the FEM＇s capability in accurate simulation of complicated geologic structure, but also increases the flexibility and comprehensiveness of limit equilibrium method. This method is reliable and recommended for further application in other real geotechnical engineering.
文摘The main focus is nonlinear model-based dynamic positioning (DP) control system design. A nonlinear uniform global exponential stability (UGES) observer produces noise-free estimates of the position, the slowly varying environmental disturbances and the velocity, which are used in a proportional-derivative (PD) + feedforward control law. The stability of this observer-controller system is proved by introducing a specific nonlinear cascaded system. The simulation results have successfully demonstrated the performance of designed DP control system.
文摘为克服筒仓结构在地震易损性评估时需要进行大量非线性时程分析的不足,采用基于耐震时程法(endurance time method,ETM)的易损性分析方法对筒仓结构进行易损性的快速评估。以IV类场地柱承式筒仓为研究对象,选取实际天然地震动记录为目标反应谱合成3条耐震时程曲线,利用有限元软件ABAQUS建立柱承式筒仓模型并输入耐震时程曲线,将ETM分析结果与增量动力分析方法(incremental dynamic analysis,IDA)结果进行对比。结果表明:ETM分析结果与IDA分析结果的中位值相匹配,满足筒仓结构抗震性能分析精度要求;筒仓不同支承柱在地震作用下的基底剪力分配情况与储料质量无关,仅取决于支承柱位置;ETM所得的筒仓地震易损性曲线与IDA易损性曲线基本吻合,耐震时程法可作为柱承式筒仓抗震性能分析、预测和评估的高效方法。
