The mechanism of ground vibration in building demolition blasting was investigated,taking into account the prevailing influential factors, including the building's heightof mass center, the quantity size, the stru...The mechanism of ground vibration in building demolition blasting was investigated,taking into account the prevailing influential factors, including the building's heightof mass center, the quantity size, the structural feature, the component material quantity,the demolition method, the geological structure of the region, earthquake resistance rank,as well as the earthquake wave dissemination.The proposed method was applied efficientlyto reduce the blasting effects on the environment, which enriches the control theoriesof vibration caused by collapse in the blasting process and may provide a good referencefor the related engineering practices.展开更多
An offshore platform of jacket type in Bohai Bay vibrated excessively under design environmental conditions, which had affected the normal operation of the platform. In order to mitigate the vibration of the platform,...An offshore platform of jacket type in Bohai Bay vibrated excessively under design environmental conditions, which had affected the normal operation of the platform. In order to mitigate the vibration of the platform, it is essentially important to explore the cause of the vibration. So the objective of this study is to investigate the cause of the excessive vibration. In this paper, dynamic characteristics of the offshore platform is analyzed by numerical simulation using finite element (FE) modeling. For further verifying the numerical results, model experiment is conducted. Numerical and experimental results demonstrate that there is relative movement and impact between the piles and the jacket, i.e. the piles and the jacket didnt connect well to an entity. It is this cause that the stiffness of the platform decreases and the impact between piles and the jacket legs induces excessive vibration. And also the grouting measure is advised to reduce the vibration of the offshore platform according to the analysis results.展开更多
A theoretical and numerical study has been performed on an air film dumper attached to a plate structure. Combined with the analysis by Fox and Whittorg a damping model of the air fiim damper has been developed. A com...A theoretical and numerical study has been performed on an air film dumper attached to a plate structure. Combined with the analysis by Fox and Whittorg a damping model of the air fiim damper has been developed. A complex stiffness was introduced to represent the air pressure in the damper cavity. The stain energy and dissipated energy were integrated from the real part and imaginary part of the complex stiffness to determine the stiffness and damping. The response of the plate with the air film damper was considered by treating the air film as multiple discrete damping-stiffness elements using ANSYS.展开更多
Systematic analysis of influence of blasting vibration on bridges,tunnels,slopes and the mechanical relationships between each other were drawn based on the example of safety argument between blasting mining area and ...Systematic analysis of influence of blasting vibration on bridges,tunnels,slopes and the mechanical relationships between each other were drawn based on the example of safety argument between blasting mining area and protected objects.The safety argument methods and technological means of controlling dangerous and harmful factors were proposed by the application of principle of risk analysis.And standard control system was established based on controlling the blasting parameters of division of blasting area.展开更多
Sensitivities of eigen-solutions to control variables play an important role in microgrid studies,such as coordinated optimal design of controllers and parameters,robust stability analysis on control variables,oscilla...Sensitivities of eigen-solutions to control variables play an important role in microgrid studies,such as coordinated optimal design of controllers and parameters,robust stability analysis on control variables,oscillation modes analysis on a system,etc.Considering the importance of sensitivities and the complexity of state matrix in a microgrid,parameter perturbations are utilized in this paper to analyze the construction characteristics of state matrix.Then,the sensitivities of eigenvalues and eigenvectors to control variables are obtained based on the first-order matrix perturbation theory,which makes the complex derivations of sensitivity formulas and repeated solutions of eigenvalue problem unnecessary.Finally,the effectiveness of the matrix perturbation based approach for sensitivity calculation in a microgrid is verified by a numerical example on a low-voltage microgrid prototype.展开更多
文摘The mechanism of ground vibration in building demolition blasting was investigated,taking into account the prevailing influential factors, including the building's heightof mass center, the quantity size, the structural feature, the component material quantity,the demolition method, the geological structure of the region, earthquake resistance rank,as well as the earthquake wave dissemination.The proposed method was applied efficientlyto reduce the blasting effects on the environment, which enriches the control theoriesof vibration caused by collapse in the blasting process and may provide a good referencefor the related engineering practices.
文摘An offshore platform of jacket type in Bohai Bay vibrated excessively under design environmental conditions, which had affected the normal operation of the platform. In order to mitigate the vibration of the platform, it is essentially important to explore the cause of the vibration. So the objective of this study is to investigate the cause of the excessive vibration. In this paper, dynamic characteristics of the offshore platform is analyzed by numerical simulation using finite element (FE) modeling. For further verifying the numerical results, model experiment is conducted. Numerical and experimental results demonstrate that there is relative movement and impact between the piles and the jacket, i.e. the piles and the jacket didnt connect well to an entity. It is this cause that the stiffness of the platform decreases and the impact between piles and the jacket legs induces excessive vibration. And also the grouting measure is advised to reduce the vibration of the offshore platform according to the analysis results.
文摘A theoretical and numerical study has been performed on an air film dumper attached to a plate structure. Combined with the analysis by Fox and Whittorg a damping model of the air fiim damper has been developed. A complex stiffness was introduced to represent the air pressure in the damper cavity. The stain energy and dissipated energy were integrated from the real part and imaginary part of the complex stiffness to determine the stiffness and damping. The response of the plate with the air film damper was considered by treating the air film as multiple discrete damping-stiffness elements using ANSYS.
文摘Systematic analysis of influence of blasting vibration on bridges,tunnels,slopes and the mechanical relationships between each other were drawn based on the example of safety argument between blasting mining area and protected objects.The safety argument methods and technological means of controlling dangerous and harmful factors were proposed by the application of principle of risk analysis.And standard control system was established based on controlling the blasting parameters of division of blasting area.
基金supported by the National Natural Science Foundation of China (Grant No. 50595412)the National Basic Research Program of China ("973" Program) (Grant No. 2009CB219700)
文摘Sensitivities of eigen-solutions to control variables play an important role in microgrid studies,such as coordinated optimal design of controllers and parameters,robust stability analysis on control variables,oscillation modes analysis on a system,etc.Considering the importance of sensitivities and the complexity of state matrix in a microgrid,parameter perturbations are utilized in this paper to analyze the construction characteristics of state matrix.Then,the sensitivities of eigenvalues and eigenvectors to control variables are obtained based on the first-order matrix perturbation theory,which makes the complex derivations of sensitivity formulas and repeated solutions of eigenvalue problem unnecessary.Finally,the effectiveness of the matrix perturbation based approach for sensitivity calculation in a microgrid is verified by a numerical example on a low-voltage microgrid prototype.
