scholarly journals VIBRATION ENERGY DISSIPATION OF A COMPOSITE MATERIAL/KOMPOZICINĖS MEDŽIAGOS VTRPESIŲ ENERGIJOS DISIPACIJA

1998 ◽  
Vol 4 (4) ◽  
pp. 280-282
Author(s):  
Petras Baradokas

The paper discusses the problem of evaluating vibration energy dissipation of a composite material. It is suggested to express the dissipation cofficient in a line (2). The reduced component dissipation coefficients c i φi are the members of the line. The ratio of reduction c i , shows the proportion by which a separate component adds to the energy dissipation of the entire composition. By analysing the accumulated and dissipated strain energy of a composite material were obtained (6). On the basis of these expressions, formulas for calculating the dissipation coefficients of a three-layer bar and that with a galvanic covering were devised. The analysis made leads to the following conclusions: - the vibration energy dissipation coefficient of a composite material is equal to the sum of the reduced dissipation coefficients of the composition component materials; - the ratio of reduction c i depends on the value of the component accumulated energy; - for comparing separate components as to the energy dissipation, the product φ i E i should be used.

2020 ◽  
Vol 8 (8) ◽  
pp. 589
Author(s):  
Mohamad Alkhalidi ◽  
Noor Alanjari ◽  
S. Neelamani

The interaction between waves and slotted vertical walls was experimentally studied in this research to examine the performance of the structure in terms of wave transmission, reflection, and energy dissipation. Single and twin slotted barriers of different slopes and porosities were tested under random wave conditions. A parametric analysis was performed to understand the effect of wall porosity and slope, the number of walls, and the incoming relative wave height and period on the structure performance. The main focus of the study was on wave transmission, which is the main parameter required for coastal engineering applications. The results show that reducing wall porosity from 30% to 10% decreases the wave transmission by a maximum of 35.38% and 38.86% for single and twin walls, respectively, increases the wave reflection up to 47.6%, and increases the energy dissipation by up to 23.7% on average for single walls. For twin-walls, the reduction in wall porosity decreases the wave transmission up to 26.3%, increases the wave reflection up to 40.5%, and the energy dissipation by 13.3%. The addition of a second wall is more efficient in reducing the transmission coefficient than the other wall parameters. The reflection and the energy dissipation coefficients are more affected by the wall porosity than the wall slope or the existence of a second wall. The results show that as the relative wave height increases from 0.1284 to 0.2593, the transmission coefficient decreases by 21.2%, the reflection coefficient decreases by 15.5%, and the energy dissipation coefficient increases by 18.4% on average. Both the transmission and the reflection coefficients increase as the relative wave length increases while the energy dissipation coefficient decreases. The variation in the three coefficients is more significant in deep water than in shallower water.


2014 ◽  
Vol 578-579 ◽  
pp. 707-710
Author(s):  
Ming Li ◽  
Ji Guang Chen ◽  
Wei Jian Zhao ◽  
Li Guo Wang

The force behavior of parallel double coupling beams (PDCB) with different width is analyzed, based on which the feasibility of this kind of beams is discussed. The loading process of the PDCB is simulated by using finite element software ABAQUS. By analyzing the hysteretic loops, skeleton curves, energy dissipation coefficient, equivalent viscous damping coefficient and ductility coefficient,the bearing capacity and seismic performance of the PDCB is studied. Through simulation, it shows that the hysteretic loops is plump, and the energy dissipation coefficient, equivalent viscous damping coefficient and ductility coefficient of this double beams is high. It can be concluded that the PDCB has good force behavior, and the beams of PDCB can work in coordination.


2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Ying-jie Kang ◽  
Ling-yun Peng

To improve the recoverability of structures following an earthquake, a Reid friction damper with self-centering characteristics is proposed and its hysteretic behavior is studied by theoretical analysis and experimental research. The main parameters of the damper are the equivalent stiffness and energy dissipation coefficient. Based on a 10-story steel frame structure, 10 energy dissipation design schemes using the proposed Reid damper are proposed. The additional equivalent damping ratios of the 10 schemes are equal, whereas the energy dissipation coefficients of the dampers are different. The vibration control effects of the energy dissipation structures are analytically investigated under four earthquake loads. The experimental results of the friction damper are in good agreement with the theoretical results, and the hysteretic behavior of the damper follows that of a typical Reid model. The seismic response and structural damage can be reduced using any of the 10 design schemes; however, the effects are different. When the energy dissipation coefficient is in the range of 0.1–0.3, the control effect on the interstory drift is better; however, the structural acceleration response and damping force of the dampers increase. When the energy dissipation coefficient is in the range of 0.6–1.0, the energy dissipation effect of the dampers is good; however, the self-centering ability is poor. Therefore, the optimum range of the energy dissipation coefficient of a Reid damper intended for energy dissipation structures should be 0.3–0.6.


2013 ◽  
Vol 405-408 ◽  
pp. 861-864
Author(s):  
Ming Li ◽  
Yong Liu ◽  
He Yuan

The force behavior of outer annular-stiffener type steel castellated beam (OATSCB) - concrete filled steel tube (CFST) is analyzed, and the feasibility of this kind of join is discussed. The loading process of the joint is simulated by using finite element software. By analyzing the hysteretic loops, skeleton curves, energy dissipation coefficient, equivalent viscous damping coefficient and ductility coefficient, the bearing capacity and seismic performance of this type of joint is studied. Before simulation, the validity of the simulation method is verified by using the previous experiment data of outer annular-stiffener type steel beam (OATSB) - CFST. It shows that the results from the finite element simulation method and the experiment are similar to each other, and the hysteretic loops is plump , the energy dissipation coefficient, equivalent viscous damping coefficient and ductility coefficient of this type of joint are high. It can be seen that this type of joint has good mechanical properties, and is easy to realize the yield mechanism of strong column weak beam.


1972 ◽  
Vol 62 (6) ◽  
pp. 1611-1619 ◽  
Author(s):  
R. W. Alewine

abstract Examination of the distance correction factor used in the widely accepted formula for surface-wave magnitude reveals that this empirically derived linear formula fails to give an accurate approximation to the theoretical nonlinear amplitude-distance relation for epicentral distances less than 15°. For epicentral distances greater than 15°, the empirical formula contains an implied oceanic-type energy-dissipation coefficient. When the original Gutenberg theoretical surface-wave magnitude formula with an appropriate continental energy-dissipation coefficient is applied to explosion data from the Nevada Test Site, a consistent surface-wave magnitude is obtained at all distances. A systematic method of normalizing Rayleigh-wave magnitudes obtained over different types of propagation paths is suggested. This normalization might provide a means for better separating natural events and explosions in the mb—Ms plots.


2011 ◽  
Vol 105-107 ◽  
pp. 848-852 ◽  
Author(s):  
Li Yun Jiang ◽  
Guo Jun Liu ◽  
Xu Dong Sun

Connection with haunch is a new type of rigid connection. Single and cyclic load test is modeled using the program ANSYS. The result under different axial-compression ratio including hysteretic curve, the energy dissipation coefficient, and the plastic angle on beam ending is ascertained. The hysteretic curve under the ratio 0.3-0.6 is stable, and shows better plastic rotation ability. It exists a limit that axial-compression ratio has an effect on the connection with haunch, the model in this paper is 0.6. With hunch, the node can not only make the relocation of the plastic angle occur, but also increase yield stiffness, ultimate load, energy dissipation coefficient, linear displacement ductility coefficient and the plastic angle of beam end.


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