A novel porous shock absorption layer is put forward in this study, and the shock absorption performance of the porous shock absorption layer is evaluated based on three-dimensional pseudo-static analysis. The modifie...A novel porous shock absorption layer is put forward in this study, and the shock absorption performance of the porous shock absorption layer is evaluated based on three-dimensional pseudo-static analysis. The modified reaction acceleration method is adopted and validated in the three-dimensional model. Seven ground motions are selected and the peak ground acceleration is adjusted to 0.2 g, 0.4 g and 0.6 g. The impact of the void ratio and thickness of the porous shock absorption layer is studied, while the surrounding rock grade and tunnel depth are also investigated. The numerical results show that the porous shock absorption layer has good shock absorption performance and can effectively reduce the maximum internal force of the secondary lining, but it cannot reduce the maximum horizontal relative displacement of the secondary lining. The circumferential rubber strip in the porous shock absorption layer will reduce shock absorption performance. The results of parameter analysis indicate that the shock absorption performance of the porous shock absorption layer increases with the increase of the void ratio and thickness, and it has good shock absorption performance under different surrounding rock grades and tunnel depths.展开更多
Mechanical properties and low cycle fatigue are two factors that must be considered in developin gnew type steel for shock absorption. Process capability and process control are significant factors in achieving the pu...Mechanical properties and low cycle fatigue are two factors that must be considered in developin gnew type steel for shock absorption. Process capability and process control are significant factors in achieving the purpose of research and development programs. Often-used evaluation methods failed to measure processyield and process centering ; so this paper uses Taguchi loss function as basis to establish an evaluation methodand the steps for assessing the quality of mechanical properties and process control of an iron and steel manu-facturer. The establishment of this method can serve the research and development and manufacturing industry and lay a foundation in enhancing its process control ability to select better manufacturing processes that are more reliable than decision making by using the other commonly used methods.展开更多
Oscillations and their damping were investigated for plant stems of Cyperus alternifolius L., Equisetum hyemale L., Equisetum fluviatile L., Juncus effuses L., Stipa gigantea Link, and Thamnocalamus spathaceus (Franc...Oscillations and their damping were investigated for plant stems of Cyperus alternifolius L., Equisetum hyemale L., Equisetum fluviatile L., Juncus effuses L., Stipa gigantea Link, and Thamnocalamus spathaceus (Franch.) Soderstr. With the exception of T. spathaceus, mechanical damping of the oscillation of individual plant stems, even without side organs, leaves or inflorescences, is quite effective. Our experiments support the hypothesis that embedding stiff sclerenchymatous elements in a more compliant parenchymatous matrix provides the structural basis for the dissipation of mechanical energy in the plant stem. As an application the naturally occurring structures were mimicked in a compound material made from hemp fabrics em- bedded in polyurethane foam, cured under pressure. Like its natural model it shows plastic deformability and viscoelastic be- haviour. In particular the material is characterized by a remarkably high shock absorption capacity even for high impact loads.展开更多
A passive energy-dissipating device, velocity, and displacement dependent hydraulic damper (VDHD), is developed to reduce the seismic response of structure. This device is comprised of a hydraulic jack, check valve, r...A passive energy-dissipating device, velocity, and displacement dependent hydraulic damper (VDHD), is developed to reduce the seismic response of structure. This device is comprised of a hydraulic jack, check valve, relief valve, and throttle valve. The numerical analysis model for SAP2000 nonlinear analysis program is proposed to simulate the energy-dissipating characteristics of VDHD. The analysis results of this model compared with the seismic resistant tests reveal that this proposed model can accurately describe the actual energy-dissipating behavior of VDHD. The efficiency of VDHD is confirmed using this proposed model for carrying out numerical analyses of bare building, building added with bulking resistant bracing (BBR), and VDHD. The energy-dissipating capabilities of VDHD are performing excellent displacement and acceleration control with various ground magnitudes; being an energy absorber to absorb mechanical energy in the structure and resist structural movement; and gathering the advantage of BRB.展开更多
基金Science and Technology Plan Project of Xizang Autonomous Region,China under Grant No.XZ202501YD0007。
文摘A novel porous shock absorption layer is put forward in this study, and the shock absorption performance of the porous shock absorption layer is evaluated based on three-dimensional pseudo-static analysis. The modified reaction acceleration method is adopted and validated in the three-dimensional model. Seven ground motions are selected and the peak ground acceleration is adjusted to 0.2 g, 0.4 g and 0.6 g. The impact of the void ratio and thickness of the porous shock absorption layer is studied, while the surrounding rock grade and tunnel depth are also investigated. The numerical results show that the porous shock absorption layer has good shock absorption performance and can effectively reduce the maximum internal force of the secondary lining, but it cannot reduce the maximum horizontal relative displacement of the secondary lining. The circumferential rubber strip in the porous shock absorption layer will reduce shock absorption performance. The results of parameter analysis indicate that the shock absorption performance of the porous shock absorption layer increases with the increase of the void ratio and thickness, and it has good shock absorption performance under different surrounding rock grades and tunnel depths.
文摘Mechanical properties and low cycle fatigue are two factors that must be considered in developin gnew type steel for shock absorption. Process capability and process control are significant factors in achieving the purpose of research and development programs. Often-used evaluation methods failed to measure processyield and process centering ; so this paper uses Taguchi loss function as basis to establish an evaluation methodand the steps for assessing the quality of mechanical properties and process control of an iron and steel manu-facturer. The establishment of this method can serve the research and development and manufacturing industry and lay a foundation in enhancing its process control ability to select better manufacturing processes that are more reliable than decision making by using the other commonly used methods.
文摘Oscillations and their damping were investigated for plant stems of Cyperus alternifolius L., Equisetum hyemale L., Equisetum fluviatile L., Juncus effuses L., Stipa gigantea Link, and Thamnocalamus spathaceus (Franch.) Soderstr. With the exception of T. spathaceus, mechanical damping of the oscillation of individual plant stems, even without side organs, leaves or inflorescences, is quite effective. Our experiments support the hypothesis that embedding stiff sclerenchymatous elements in a more compliant parenchymatous matrix provides the structural basis for the dissipation of mechanical energy in the plant stem. As an application the naturally occurring structures were mimicked in a compound material made from hemp fabrics em- bedded in polyurethane foam, cured under pressure. Like its natural model it shows plastic deformability and viscoelastic be- haviour. In particular the material is characterized by a remarkably high shock absorption capacity even for high impact loads.
基金the Science Council of Taiwan, Chinese Taipei (No. NSC-96-2625-Z-167-001)
文摘A passive energy-dissipating device, velocity, and displacement dependent hydraulic damper (VDHD), is developed to reduce the seismic response of structure. This device is comprised of a hydraulic jack, check valve, relief valve, and throttle valve. The numerical analysis model for SAP2000 nonlinear analysis program is proposed to simulate the energy-dissipating characteristics of VDHD. The analysis results of this model compared with the seismic resistant tests reveal that this proposed model can accurately describe the actual energy-dissipating behavior of VDHD. The efficiency of VDHD is confirmed using this proposed model for carrying out numerical analyses of bare building, building added with bulking resistant bracing (BBR), and VDHD. The energy-dissipating capabilities of VDHD are performing excellent displacement and acceleration control with various ground magnitudes; being an energy absorber to absorb mechanical energy in the structure and resist structural movement; and gathering the advantage of BRB.
