Papers by Keyword: Energy Dissipation

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Authors: Yuan Xue Liu, Zhong You Li, Jian Ting Zhou, Shu Guo Sun
Abstract: Set out from a basic idea that damage is a course of energy dissipation, a new damage variable is present. The damage variable is obtained for arbitrary strain state of soil according to the superimposing principle of compatible probability event for volumetric strain and shear strain. Through the analysis of a series of triaxial experimental results of structured soil, a new damage evaluation equation is put forward. The computation results tally with the experimental data show it is reasonable that this new damage variable and its evaluation law for structured soil.
Authors: Ai Rong Liu, Qi Cai Yu, Yuan Yao, Yu Zhu Guo
Abstract: This paper investigated the superelasticity and hysteresis characteristics of TiNi shape memory alloy ( SMA ) wire at room temperature, then the mechanical parameters of which were obtained. Based on the TiNi SMA wire and a purchased viscous damper, a new type of hybrid-passive-damper was designed and developed. Experiments were performed in order to validate the relationship of loading frequency and characteristic parameters such as energy dissipation capacity, equivalent damping ratio and equivalent stiffness. Experimental results show that hybrid-passive-damper designed in this paper has excellent energy dissipation capacity and is suitable for the vibration control of structures with long vibration period.
Authors: Min Chen, Guo Jing He, Chang Liu
Abstract: Energy dissipation structure is favored by designers because the earthquake energy can be dissipated by the dampers, which can avoid or reduce the damage caused by earthquake. However, the energy dissipation structure design is complex and the most domestic designers can not master it easily. In this paper, a simple and practicable design method for viscous damper dissipation structure by using the PKPM design software is proposed based on a 7-storey frame structure in highly seismic region. Firstly, lower half or one degree for the design intensity to design out an uncontrolled structure. Secondly, determine the supplemental damping ratio required for the fortification intensity via modal analysis method of PKPM software, and identify the numbers of the required dampers as well as their corresponding installation positions in line with the methods in the seismic code of China. Finally, the ETABS program is adopted to conduct the time-history analysis of the designed dissipation structure, showing that the proposed method in this paper can produce a satisfied result.
Authors: Chang Wu, Xiu Li Wang
Abstract: In this study a kind of buckling-restrained braces (BRBs) as energy dissipation dampers is attempted for seismic performance of large span double-layer reticulated shell and the effectiveness of BRBs to protect structures against strong earthquakes is numerically studied. The hysteretic curve of such members is obtained through the simulation of the cyclic-loading test, and the equations of motion of the system under earthquake excitations are established. BRBs are then placed at certain locations on the example reticulated shell to replace some normal members, and the damping effect of the two installation schemes of BRBs is investigated by non-linear time-history analyses under various ground motions representing major earthquake events. Compared with the seismic behavior of the original structure without BRBs, satisfactory seismic performance is seen in the upgraded models, which clarifies the BRBs can reduce the vibration response of spatial reticulated structure effectively and the new system has wide space to develop double layer reticulated shell.
Authors: Zhen Huang, Zuo Wei Qin, Peng Wu
Abstract: This paper presents a reinforcement design of five-story R/C structure with mild steel dampers in high seismic fortification intensity site. The details of the design process are listed in the paper, and the time history analyses under frequent and rare earthquake are performed on structure models with and without dampers. Through the comparison, the peak of maximum story drifts angles with damper-added structural is reduced by 38% and the distribution is more uniformly. The results show that energy-dissipation design with mild steel dampers can be a reliable and effective method in reducing seismic responses of reinforcement structure.
Authors: Min Sheng Guan, Da Jian Han, Hong Biao Du, Xin Wang
Abstract: Earthquake input energy and structural energy dissipation are key indicators to assess the seismic performance of structures. To study the rules of distribution of hysteretic energy within structures, a 6-storey regular reinforced concrete frame structure model is analyzed through elasto-plastic time-history dynamic analysis using the El Centro and Northridge accelerograms. Based on the comparison between numerical results for the earthquake input energy and structural hysteretic energy under the minor, moderate and major earthquakes of Grade 8 and 9, the distribution of the ratio of the storey hysteretic energy to the total hysteretic energy through the height was further studied. It shows that the computed results corresponding to the two earthquake records are in good agreement under different ground motion severity. And the percentage of structural hysteretic energy to input energy is basically stable. The distribution pattern of storey hysteretic energy through the height is that the value of the upper stories is smaller than the value of the lower stories. And the ground motion severity has a minor influence on the distribution pattern when the plasticity of structure develops more sufficiently.
Authors: Pu Yang, Jing Tang
Abstract: Using flexibility-based finite element method based on fiber model, several experiments of reinforced concrete specially shaped columns under cyclic loading which cross section is ‘L’, ‘T’ and ‘+’ shape with different longitudinal reinforcement and hoop reinforcement have been simulated, and the seismic behavior of columns such as strength, ductility and energy dissipation are analyzed. Results from the analytical study indicate that: 1) ductility of the column increases as quantity of hoop reinforcement increases. 2) strength capacity of the column increase linearly as ratio of longitudinal reinforcement increase, but is not seriously affected by hoop reinforcement; 3) energy dissipation capacity of the column is not significantly affected by hoop and longitudinal reinforcement, particularly in slightly nonlinear range.
Authors: Shao Wei Hu, Zheng Xiang Mi, Jun Lu
Abstract: The mechanical performance of concrete structures closely relates to the propagation of cracks. Depth studying energy dissipation of concrete in fracture process zone not only contributes to comprehensive understanding fracture failure mechanism of concrete, but also has significant in detecting and forecasting the cracks in actual structure. In view of this, a general equation for calculating at any time’s mean energy dissipation per unit length was given. After that, we further simplified and deduced the general equation and got a simple, practical and high accuracy numerical solution, with which Gauss integration method was used. At last, the specific steps of calculating mean energy dissipation were given by taking 10 three-point bending beams of different crack-depth ratios for an example. Compared with test dates, we found that calculated results are in good agreement with the test dates. According to results, influence of crack-depth ratio on the fracture energy was also discussed.
Authors: Giovanni Meneghetti, Mauro Ricotta, L. Negrisolo, Bruno Atzori
Abstract: In previous papers, the energy dissipated to the surroundings as heat in a unit volume of material per cycle, Q, has been successfully applied to correlate experimental data generated from push-pull, stress- or strain-controlled fatigue tests on AISI 304 L stainless steel plain and notched specimens. In this paper the fatigue behaviour of AISI 304 L un-notched bars under fully-reversed axial or torsional loading was investigated. By using the Q parameter it was found that the experimental data collapse into the same energy-based scatter band previously determined with the push-pull tests. The results found in the present contribution are meant to be specific for the material investigated.
Authors: Xi Qing Li, Lin Liu
Abstract: Focusing on the green renovation project of Shendu Building in Shanghai, China, an evaluation system is developed for the comparison of a variety of seismic control schemes for seismic retrofit of the building. A three-dimensional evaluation model is developed in MATLAB to represent the dynamic features of the structural system of the building, and nine key evaluation indices are defined for the evaluation purpose from a global view of both control efficiency and costs. The complete procedure of designing control schemes based on the retrofitted benchmark structure is presented, which may be helpful for researchers and engineers in easily testing various control schemes by using this evaluation system.
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