In this study, through novel drift-based equations of motion in the frequency domain, optimum placement and characteristics of linear velocity-dependent dampers are investigated. In this study, the sum of the square o...In this study, through novel drift-based equations of motion in the frequency domain, optimum placement and characteristics of linear velocity-dependent dampers are investigated. In this study, the sum of the square of the absolute values of transfer matrix elements for interstory drifts is considered as the optimization index. Optimum placement and characteristics of dampers are simultaneously obtained by minimizing the optimization index through an incremental procedure. In each step of the procedure, a predefined value is considered as the damper characteristic. The optimum story for this increment is selected such that it leads to a minimum value for the optimization index. The procedure is repeated for the next increments until the optimization index meets its target value, which is obtained according to the desired damping ratio for the overall structure. In other words, the desired overall damping ratio is the input to the proposed procedure, and the optimal placement and characteristics of the dampers are its output. It is observed that the optimal placement of a velocitydependent damper depends on the damping coefficient of the added damper, frequency of the excitation, and distribution of the mass, stiffness, and inherent damping of the main structure.展开更多
Thermal resistance was composed by thermal resistance of Aluminum substrate, thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through the cal...Thermal resistance was composed by thermal resistance of Aluminum substrate, thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through the calculation on Aluminum plate thermal resistance, thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. Its change regular- ity was simulated by toolbox In the MATLAB, and it was found that thermal resistance of convective heat transfer effect on the effi- ciency was most obvious in a certain amount of the heat and flow for thermal resistance of the Pin-fin radiator under the premise. The structural parameters of radiator were related to the size of thermal resistance.展开更多
在传统感应耦合电能传输(inductively coupled power transfer,ICPT)系统拓扑中,系统谐振频率漂移会引起传输效率下降。针对该问题,提出一种新型的基于LCL谐振型ICPT系统拓扑。采用基波分析法对其等效电路模型进行分析,得出不同品质因数...在传统感应耦合电能传输(inductively coupled power transfer,ICPT)系统拓扑中,系统谐振频率漂移会引起传输效率下降。针对该问题,提出一种新型的基于LCL谐振型ICPT系统拓扑。采用基波分析法对其等效电路模型进行分析,得出不同品质因数下,系统的电压、电流增益与开关频率的特性曲线,并分析得出该拓扑具有较高的功率因数。为实现了ICPT系统软开关,提出了谐振元件参数优化设计的方法。基于所优化的参数结果,分析了品质因数和耦合系数的选择对谐振元件电压电流应力的影响。最后,设计了一台基于LCL谐振型ICPT系统样机,实验结果证明了所提方法的可行性。展开更多
基金National Natural Science Foundation of China Under Grant No.50638010the Foundation of Ministry of Education for Innovation Group Under Grant No.IRT0518
文摘In this study, through novel drift-based equations of motion in the frequency domain, optimum placement and characteristics of linear velocity-dependent dampers are investigated. In this study, the sum of the square of the absolute values of transfer matrix elements for interstory drifts is considered as the optimization index. Optimum placement and characteristics of dampers are simultaneously obtained by minimizing the optimization index through an incremental procedure. In each step of the procedure, a predefined value is considered as the damper characteristic. The optimum story for this increment is selected such that it leads to a minimum value for the optimization index. The procedure is repeated for the next increments until the optimization index meets its target value, which is obtained according to the desired damping ratio for the overall structure. In other words, the desired overall damping ratio is the input to the proposed procedure, and the optimal placement and characteristics of the dampers are its output. It is observed that the optimal placement of a velocitydependent damper depends on the damping coefficient of the added damper, frequency of the excitation, and distribution of the mass, stiffness, and inherent damping of the main structure.
文摘Thermal resistance was composed by thermal resistance of Aluminum substrate, thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through the calculation on Aluminum plate thermal resistance, thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. Its change regular- ity was simulated by toolbox In the MATLAB, and it was found that thermal resistance of convective heat transfer effect on the effi- ciency was most obvious in a certain amount of the heat and flow for thermal resistance of the Pin-fin radiator under the premise. The structural parameters of radiator were related to the size of thermal resistance.
文摘在传统感应耦合电能传输(inductively coupled power transfer,ICPT)系统拓扑中,系统谐振频率漂移会引起传输效率下降。针对该问题,提出一种新型的基于LCL谐振型ICPT系统拓扑。采用基波分析法对其等效电路模型进行分析,得出不同品质因数下,系统的电压、电流增益与开关频率的特性曲线,并分析得出该拓扑具有较高的功率因数。为实现了ICPT系统软开关,提出了谐振元件参数优化设计的方法。基于所优化的参数结果,分析了品质因数和耦合系数的选择对谐振元件电压电流应力的影响。最后,设计了一台基于LCL谐振型ICPT系统样机,实验结果证明了所提方法的可行性。
