It is well known that there are some torsional damages in earthquakes. In Taibai park, Jiangyou city, Sichuan province, most of the stone statues, which were placed upon the banisters of one zigzag bridge, exhibited d...It is well known that there are some torsional damages in earthquakes. In Taibai park, Jiangyou city, Sichuan province, most of the stone statues, which were placed upon the banisters of one zigzag bridge, exhibited different torsional phenomena in 2008 Wenchuan earthquake. This paper introduces the torsional phenomena of all the statues on the zigzag bridge firstly. Then one eccentric- ity model is established and the equivalent rotational accelerations are calculated in order to analyze the causes of the torsional damage. In addition, the torsional components are synthesized by using translation accelerations recorded at Jiangyou station in the Wenchuan earthquake. The results show that the equivalent rotational acceleration is larger than the synthesized rotational components, which sug- gests that the torsional phenomena of the statues on the zigzag bridge might mainly come from its eccentricity. The comparison between the estimated torsional component at Jiangyou and that presented by Trifunac shows that they are in the same order. The research im- plies that the torsional phenomena in earthquakes are very complicated, and not only caused by torsional motions.展开更多
The effects of torsional component of earthquake ground motion on thin cylindric shell structures were investigated qualitatively and quantitatively.The results show that the contributions of torsional component to st...The effects of torsional component of earthquake ground motion on thin cylindric shell structures were investigated qualitatively and quantitatively.The results show that the contributions of torsional component to structural response are related to the height,the radius-to-height ratio,and the stiffness of the structure.The structural response caused by torsional component can not be neglected for the containment structure of nuclear power plant and the industrial oil tank.展开更多
A structure consisting of a spiral piezoelectric transducer and a concentrated mass is proposed as a low-frequency piezoelectric power harvester. A theoretical model is developed for the system from the theory of piez...A structure consisting of a spiral piezoelectric transducer and a concentrated mass is proposed as a low-frequency piezoelectric power harvester. A theoretical model is developed for the system from the theory of piezoelectricity. An analysis is performed to demonstrate the low-frequency nature of the system. Other basic characteristics of the power harvester including the output power, voltage, and efficiency are also calculated and examined.展开更多
Concerning the theoretical estimation of internal reorganization energy contributed by the tortional motion between biphenyl and biphenyl anion radical, direct calculation of self-exchange electron transfer reaction w...Concerning the theoretical estimation of internal reorganization energy contributed by the tortional motion between biphenyl and biphenyl anion radical, direct calculation of self-exchange electron transfer reaction was investigated. With the introduction of a proper average bond length and angle parameters <bond Bp>, a multiple step relaxation Nelson method was developed to deal with the torsional reorganization energy. Based on the above model, an estimation of pure torsional reorganization energy λ t,p with an approximation of λ t,1 was achieved. The results of 0.140 and 0.125 eV of torsional reorganization energy for a cross-reaction at the levels of 4-31G and HP/DZP, respectively, are in good agreement with the value of 0.13 eV obtained by Miller et al. from the rate measurements. This implies the efficiency and validity of our method to estimate the reorganization energy contributed by pure torsional motion of Bp.展开更多
This paper investigates the boundary layer flow of the Maxwell fluid around a stretchable horizontal rotating cylinder under the influence of a transverse magnetic field.The constitutive flow equations for the current...This paper investigates the boundary layer flow of the Maxwell fluid around a stretchable horizontal rotating cylinder under the influence of a transverse magnetic field.The constitutive flow equations for the current physical problem are modeled and analyzed for the first time in the literature.The torsional motion of the cylinder is considered with the constant azimuthal velocity E.The partial differential equations(PDEs)governing the torsional motion of the Maxwell fluid together with energy transport are simplified with the boundary layer concept.The current analysis is valid only for a certain range of the positive Reynolds numbers.However,for very large Reynolds numbers,the flow becomes turbulent.Thus,the governing similarity equations are simplified through suitable transformations for the analysis of the large Reynolds numbers.The numerical simulations for the flow,heat,and mass transport phenomena are carried out in view of the bvp4c scheme in MATLAB.The outcomes reveal that the velocity decays exponentially faster and reduces for higher values of the Reynolds numbers and the flow penetrates shallower into the free stream fluid.It is also noted that the phenomenon of stress relaxation,described by the Deborah number,causes to decline the flow fields and enhance the thermal and solutal energy transport during the fluid motion.The penetration depth decreases for the transport of heat and mass in the fluid with the higher Reynolds numbers.An excellent validation of the numerical results is assured through tabular data with the existing literature.展开更多
基金supported by the National Natural Science Foundation of China (No. 50578125)
文摘It is well known that there are some torsional damages in earthquakes. In Taibai park, Jiangyou city, Sichuan province, most of the stone statues, which were placed upon the banisters of one zigzag bridge, exhibited different torsional phenomena in 2008 Wenchuan earthquake. This paper introduces the torsional phenomena of all the statues on the zigzag bridge firstly. Then one eccentric- ity model is established and the equivalent rotational accelerations are calculated in order to analyze the causes of the torsional damage. In addition, the torsional components are synthesized by using translation accelerations recorded at Jiangyou station in the Wenchuan earthquake. The results show that the equivalent rotational acceleration is larger than the synthesized rotational components, which sug- gests that the torsional phenomena of the statues on the zigzag bridge might mainly come from its eccentricity. The comparison between the estimated torsional component at Jiangyou and that presented by Trifunac shows that they are in the same order. The research im- plies that the torsional phenomena in earthquakes are very complicated, and not only caused by torsional motions.
文摘The effects of torsional component of earthquake ground motion on thin cylindric shell structures were investigated qualitatively and quantitatively.The results show that the contributions of torsional component to structural response are related to the height,the radius-to-height ratio,and the stiffness of the structure.The structural response caused by torsional component can not be neglected for the containment structure of nuclear power plant and the industrial oil tank.
基金supported by the National Natural Science Foundation of China(Nos.10932004 and 11272127)
文摘A structure consisting of a spiral piezoelectric transducer and a concentrated mass is proposed as a low-frequency piezoelectric power harvester. A theoretical model is developed for the system from the theory of piezoelectricity. An analysis is performed to demonstrate the low-frequency nature of the system. Other basic characteristics of the power harvester including the output power, voltage, and efficiency are also calculated and examined.
文摘Concerning the theoretical estimation of internal reorganization energy contributed by the tortional motion between biphenyl and biphenyl anion radical, direct calculation of self-exchange electron transfer reaction was investigated. With the introduction of a proper average bond length and angle parameters <bond Bp>, a multiple step relaxation Nelson method was developed to deal with the torsional reorganization energy. Based on the above model, an estimation of pure torsional reorganization energy λ t,p with an approximation of λ t,1 was achieved. The results of 0.140 and 0.125 eV of torsional reorganization energy for a cross-reaction at the levels of 4-31G and HP/DZP, respectively, are in good agreement with the value of 0.13 eV obtained by Miller et al. from the rate measurements. This implies the efficiency and validity of our method to estimate the reorganization energy contributed by pure torsional motion of Bp.
文摘This paper investigates the boundary layer flow of the Maxwell fluid around a stretchable horizontal rotating cylinder under the influence of a transverse magnetic field.The constitutive flow equations for the current physical problem are modeled and analyzed for the first time in the literature.The torsional motion of the cylinder is considered with the constant azimuthal velocity E.The partial differential equations(PDEs)governing the torsional motion of the Maxwell fluid together with energy transport are simplified with the boundary layer concept.The current analysis is valid only for a certain range of the positive Reynolds numbers.However,for very large Reynolds numbers,the flow becomes turbulent.Thus,the governing similarity equations are simplified through suitable transformations for the analysis of the large Reynolds numbers.The numerical simulations for the flow,heat,and mass transport phenomena are carried out in view of the bvp4c scheme in MATLAB.The outcomes reveal that the velocity decays exponentially faster and reduces for higher values of the Reynolds numbers and the flow penetrates shallower into the free stream fluid.It is also noted that the phenomenon of stress relaxation,described by the Deborah number,causes to decline the flow fields and enhance the thermal and solutal energy transport during the fluid motion.The penetration depth decreases for the transport of heat and mass in the fluid with the higher Reynolds numbers.An excellent validation of the numerical results is assured through tabular data with the existing literature.
