scholarly journals Theoretical and observed distance corrections for Rayleigh-wave magnitude

1972 ◽  
Vol 62 (6) ◽  
pp. 1611-1619 ◽  
Author(s):  
R. W. Alewine
Keyword(s):  
Surface Wave ◽  
Energy Dissipation ◽  
Rayleigh Wave ◽  
Test Site ◽  
Nevada Test Site ◽  
Surface Wave Magnitude ◽  
Dissipation Coefficient ◽  
Distance Relation ◽  
Energy Dissipation Coefficient ◽  
Distance Correction

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.

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
Keyword(s):  
Composite Material ◽  
Energy Dissipation ◽  
Strain Energy ◽  
Vibration Energy ◽  
Separate Component ◽  
Dissipation Coefficient ◽  
Energy Dissipation Coefficient

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.

scholarly journals Wave Interaction with Single and Twin Vertical and Sloped Slotted Walls

2020 ◽  
Vol 8 (8) ◽  
pp. 589
Author(s):  
Mohamad Alkhalidi ◽  
Noor Alanjari ◽  
S. Neelamani
Keyword(s):  
Energy Dissipation ◽  
Transmission Coefficient ◽  
Wave Height ◽  
Wave Reflection ◽  
Wave Length ◽  
Wave Interaction ◽  
Wave Transmission ◽  
Random Wave ◽  
Dissipation Coefficient ◽  
Energy Dissipation Coefficient

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.

scholarly journals Determining surface-wave magnitudes from regional Nevada Test Site data

1995 ◽  
Vol 120 (2) ◽  
pp. 474-498 ◽  
Author(s):  
Bradley B. Woods ◽  
David G. Harkrider
Keyword(s):  
Surface Wave ◽  
Test Site ◽  
Nevada Test Site

Force Behavior of Parallel Double Coupling Beams with Different Width

2014 ◽  
Vol 578-579 ◽  
pp. 707-710
Author(s):  
Ming Li ◽  
Ji Guang Chen ◽  
Wei Jian Zhao ◽  
Li Guo Wang
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Damping Coefficient ◽  
Viscous Damping ◽  
Coupling Beams ◽  
Equivalent Viscous Damping ◽  
Dissipation Coefficient ◽  
Finite Element Software ◽  
Double Coupling ◽  
Energy Dissipation Coefficient

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.

scholarly journals Development and Analysis of the Control Effect of a Reid Damper with Self-Centering Characteristics

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Ying-jie Kang ◽  
Ling-yun Peng
Keyword(s):  
Energy Dissipation ◽  
Structural Damage ◽  
Hysteretic Behavior ◽  
Frame Structure ◽  
Friction Damper ◽  
Control Effect ◽  
Damping Force ◽  
Dissipation Coefficient ◽  
Equivalent Damping ◽  
Energy Dissipation Coefficient

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.

Force Behavior of Outer Annular-Stiffener Type Steel Castellated Beam-Concrete Filled Steel Tuber

2013 ◽  
Vol 405-408 ◽  
pp. 861-864
Author(s):  
Ming Li ◽  
Yong Liu ◽  
He Yuan
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Simulation Method ◽  
Damping Coefficient ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Type Steel ◽  
Dissipation Coefficient ◽  
Castellated Beam ◽  
Energy Dissipation Coefficient

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.

Bias in surface-wave magnitude Ms due to inadequate distance corrections

1998 ◽  
Vol 88 (1) ◽  
pp. 43-61
Author(s):  
Mehdi Rezapour ◽  
Robert G. Pearce
Keyword(s):  
Surface Wave ◽  
Wave Amplitude ◽  
Body Wave ◽  
The Body ◽  
Body Waves ◽  
P Wave ◽  
Systematic Bias ◽  
Surface Wave Magnitude ◽  
Distance Curve ◽  
Distance Correction

Abstract We investigate bias in surface-wave magnitude using the complete ISC and NEIC datasets from 1978 to 1993. We conclude that although there are some small differences between the ISC and NEIC magnitudes, there is no major difference between these agencies for this presentation of the global dataset. The frequency-distance plot for reported surface-wave amplitude observations exhibits detailed structure of the body-wave amplitude-distance curve at all distances; the influence of the surface-wave amplitude decay with distance is much less apparent. This censoring via the body waves represents a large deficit in the number of potentially usable surface-wave amplitude observations, particularly in the P-wave shadow zone between Δ = 100° and 120°. We have obtained two new modified Ms formulas based upon analysis of all ISC data between 1978 and 1993. In the first, the conventional logarithmic dependence of the distance correction is retained, and we obtain M s e = log ( A / T ) max + 1.155 log ( Δ ) + 4.269 . In the second, we make allowance for the theoretically known contribution of dispersion and geometrical spreading, to obtain M s t = log ( A / T ) max + 1 3 log ( Δ ) + 1 2 log ( sin Δ ) + 0.0046 Δ + 5.370. Comparison of these formulas with other work confirms the inadequacy of the distance-dependence term in the Gutenberg and Prague formulas, and we show that our first formula, as well as that of Herak and Herak, gives less bias at all epicentral distances to within the scatter of the observed dataset. Our second formula provides an improved overall distance correction, especially beyond Δ = 145°. We show evidence that Airy-phase distance decay predominates at shorter distances (Δ≦30°), but for greater distances, we are unable to resolve whether this or non-Airy-phase decay predominates. Assuming 20-sec surface waves with U = 3.6 km/sec, we obtain a globally averaged apparent Q−1 of 0.00192 ± 0.00026 (Q ≈ 500). We argue that our second formula not only improves the distance correction for surface-wave magnitudes but also promotes the analysis of unexplained amplitude anomalies by formally allowing for those contributions that are theoretically predictable. We conclude that there remains systematic bias in station magnitudes and that this includes the effects of source depth, different path contributions, and differences in seismometer response. For intermediate magnitudes, Mts shows less scatter against log M0 than does Ms calculated using the Prague formula.

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