Three-Dimensional Simulations of Strong Ground Motion in the Shidian Basin

2014 ◽  
Vol 501-504 ◽  
pp. 1447-1452
Author(s):  
Yan Yan Yu ◽  
Qi Fang Liu
Keyword(s):  
Surface Wave ◽  
Ground Motion ◽  
Seismic Waves ◽  
Three Dimensional ◽  
Spectral Element ◽  
Low Velocity ◽  
Computing Technique ◽  
Soil Deposits ◽  
Basin Edge ◽  
The Impact

Seismic response of the Shidian basin to moderate scenario earthquake is investigated considering 3D basin model incorporated with real topography by using the spectral-element method and parallel computing technique. The wave propagation process, the generation of surface wave, and the impact of soil deposits velocity to the basin-induced surface wave are studied in this paper. The results show that the amplification behavior of the basin is the interactions of basin geometry and low velocity soil deposits. First, locally small hollows in the basin are apt to trap seismic waves and produce much stronger ground motion, basin edge and areas with deep sediments are also characterized with large amplification. Then, basin with softer soil deposits produces stronger surface waves with lower propagation velocity and higher mode.

Enhancement of performance of three-dimensional fiber metal laminates under low velocity impact – A coupled numerical and experimental investigation

2017 ◽  
Vol 21 (6) ◽  
pp. 2127-2153 ◽  
Author(s):  
Zohreh Asaee ◽  
Farid Taheri
Keyword(s):  
Three Dimensional ◽  
Absorption Capacity ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Fiber Metal Laminates ◽  
Velocity Impact ◽  
Finite Element Software ◽  
Fiber Metal ◽  
Time And Energy ◽  
The Impact

The main objective of the present study is to examine the level of enhancement in performance of three-dimensional fiber metal laminates (3DFML) under low velocity impact, when reinforced by different types of reinforcing face-sheets (i.e. fiberglass or carbon). Three layup configurations of the fabrics are considered in this investigation. The impact response of each of these configurations is assessed numerically using ABAQUS/Explicit, a commercially available finite element software. Specifically, each configuration’s impact capacity, deformation, contact time, and energy absorption capacity are evaluated. The numerical results are validated by comparison against experimental results. Moreover, a semi-empirical equation is developed for evaluating the impact capacity of such panels, as a function of impact energy, capable of accounting the influence of any type of reinforcement. Finally, the most efficient reinforced three-dimensional fiber metal laminates are identified based on their impact strength with respect to their overall weight and cost.

The Effect of the Impactor Diameter and Boundary Conditions on Low Velocity Impact Composites Behaviour

2007 ◽  
Vol 7-8 ◽  
pp. 217-222 ◽  
Author(s):  
Ana M. Amaro ◽  
Paulo N.B. Reis ◽  
A.G. Magalhães ◽  
Marcelo F.S.F. de Moura
Keyword(s):  
Boundary Conditions ◽  
Damage Model ◽  
Testing Machine ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Energies ◽  
The Impact

The aim of present work is to study the influence of the impactor diameter and boundary conditions on low velocity impact on carbon-fibre-reinforced epoxy laminates. Experimental tests were performed on [04,904]s laminates, using a drop weight-testing machine. Circular plates were tested under low velocity impacts for two diameters of the hemispherical impactor, 12.7 mm and 20 mm, and considering similar impact energies, 2.6 J for the first impactor and 3 J for the second one. Rectangular and square plates were analysed under low velocity impacts with different boundary conditions. The impacted plates were inspected by X-radiography. Numerical simulations were also performed considering interface finite elements compatible with three-dimensional solid elements including a cohesive mixed-mode damage model, which allows to model delamination between layers. The impact tests showed that both the impactor’s diameter and boundary conditions have influence on the delaminated area. Good agreement between experimental and numerical analysis for shape, orientation and size of damage was obtained.

Experimental Research on Low-Velocity Impact Properties of 3D Braided Composites

2010 ◽  
Vol 97-101 ◽  
pp. 1741-1744
Author(s):  
Qi Jia ◽  
Ya Nan Jiao
Keyword(s):  
Three Dimensional ◽  
Low Velocity Impact ◽  
Braided Composites ◽  
Low Velocity ◽  
Impact Properties ◽  
Damage Area ◽  
3D Braided Composites ◽  
Glass Fiber Reinforced ◽  
Braiding Angle ◽  
The Impact

This research dealt with the impact properties of glass fiber reinforced composites manufactured from different structures of three-dimensional braided preforms. Three different architectures of the braid structures, 4-Direction, 5-Direction and 6-Direction, were investigated together with three further various braiding angles of each architecture. The effect of architecture and braiding angle parameters upon the impact was examined. Damage morphology of the impacted materials was characterized. It has been found that the parameters affected the damage resistance and tolerance of composites evidently. 6-Directional composites showed higher impact toughness than the others with same braiding angle. Failure of the specimens with small damage area revealed the brittle characteristic of 3D braided composite.

scholarly journals Nevşehir Castle Region in Turkey Interpreted by the Use of Seismic Surface Wave and Electrical Resistance Measurements Together

2019 ◽  
Vol 3 (2) ◽  
pp. 9-19
Author(s):  
Özcan Çakır ◽  
Nart Coşkun ◽  
Murat Erduran
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Three Dimensional ◽  
High Resistivity ◽  
Depth Range ◽  
Low Velocity ◽  
Wave Measurements ◽  
Seismic Surface Waves ◽  
Void Structure ◽  
Visualization Techniques

AbstractThe underground city beneath the Nevşehir Castle located in the middle of Cappadocia region in Turkey with approximately cone shape is investigated by jointly utilizing the modern geophysical techniques of seismic surface waves and electrical resistivity. The systematic void structure under the Nevşehir Castle of Cappadocia, which is known to have widespread underground cities, is studied by the use of 33 separate two-dimensional profiles ~4-km long where electrical resistivities and seismic surface waves are concurrently measured. Seismic surface wave measurements are inverted to establish the shear-wave velocity distribution while resistivity measurements are inverted to resolve the resistivity distribution. Several high-resistivity anomalies with a depth range 8-20 m point to a systematic void structure beneath the Nevşehir Castle. We were able to effectively isolate the void structure from the embedding structure since the currently employed resistivity instrument has provided us high resolution quality measurements. Associated with the high resistivity anomalies there exist low-velocity depth zones acquired from the surface wave inversions also pointing to a systematic void structure where three-dimensional visualization techniques are used to show the extension of the void structure under the studied area.

Influence of subduction zone complexities on teleseismic records

2020 ◽  
Author(s):  
Hector Perez Alemany ◽  
Anthony Sladen ◽  
Vadim Monteiller ◽  
Bertrand Delouis
Keyword(s):  
Seismic Waves ◽  
Accretionary Prism ◽  
Global Scale ◽  
Strong Impact ◽  
Low Velocity ◽  
Waveform Modeling ◽  
Velocity Models ◽  
Finite Fault ◽  
Seismic Networks ◽  
The Impact

<blockquote>Small and large subduction earthquakes are mostly occurring underwater away from seismic networks. Teleseismic <br />data are thus essential to characterize these seismic events. Nevertheless, teleseismic waveform modeling is usually performed using 1D velocity models that do not take into account the effects associated to heterogenities near the source, such as bathymetry and the dipping of the subducted oceanic plate. With traditional simulation tools, it is computationally too expensive to simulate high frequency seismic waves propagation at the global scale. We circumvent this problem with a hybrid method that limits the full 3D simulation to the subduction <br />area while assuming a 1D model at the global scale. We study the impact of these complexities at different frequencies. We highlight the strong influence of the water column and low velocity regions (e.g. accretionary prism). In some cases, the influence extends to relatively long periods, above 20s. We also investigate the influence of refined Green's function on finite-fault inversions, as even small changes are expected to have a strong impact on the inferred slip distribution. </blockquote> <p> </p> <div class="moz-txt-sig"><span class="moz-txt-tag"> </span></div>

High-Resolution Seismic Hazard Analysis in a Complex Geological Configuration: The Case of the Sulmona Basin in Central Italy

2014 ◽  
Vol 30 (4) ◽  
pp. 1801-1824 ◽  
Author(s):  
Manuela Villani ◽  
Ezio Faccioli ◽  
Mario Ordaz ◽  
Marco Stupazzini
Keyword(s):  
High Resolution ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Near Field ◽  
Central Italy ◽  
Three Dimensional ◽  
Spectral Element ◽  
Seismic Wave Propagation ◽  
Novel Approach

This work proposes a novel approach for probabilistic seismic hazard analyses (PSHA) in the near field of active earthquake faults, in which deterministically computed ground motion scenarios, replacing empirically predicted ground motion values, are introduced. In fact, the databases of most ground motion prediction equations (GMPEs) tend to be insufficiently constrained at short distances and data may only partially account for the rupture process, seismic wave propagation and three-dimensional (3-D) complex configurations. Hence, herein, 3-D numerical simulations of a Mw = 6.4 earthquake rupture of the Sulmona fault in Central Italy, are carried out through the spectral element code GeoELSE ( f < 2.5 Hz), and the results are introduced in a PSHA, exploiting the capabilities of CRISIS2008 code. The SH results obtained highlight the combined effects of site, basin, and topographic features, and provide a “high-resolution” representation of the hazard in the Sulmona Basin, particularly at long periods. Such representation is expected to be more realistic than those based simply on a GMPE.

scholarly journals Impact Response and Damage Characteristics of Carbon Fiber Reinforced Aluminum Laminates Under Low Velocity Impact Loading

2020 ◽  
Vol 9 (4) ◽  
pp. 1831-1837
Keyword(s):  
Impact Energy ◽  
Impact Load ◽  
Three Dimensional ◽  
Low Velocity Impact ◽  
Fe Model ◽  
Low Velocity ◽  
Fiber Layer ◽  
Cross Sectional ◽  
Velocity Impact ◽  
The Impact

CARALL hybrid material has been extensively used in the aircraft structure due to their competitive impact strength. Low velocity impact test is utilized to evaluate the impact and damage properties for such material. It is also employed to observe complex damage mechanisms. A numerical modelling is an alternative way for impact assessment. This paper investigates the impact and damage properties under low velocity impact using numerical modeling and experimental work. A three-dimensional (3D) finite element (FE) model was devolved and validated with two studies from the literature. This model was meshed with solid elements. It was subjected to 2.4 m/s impact velocity and to 10 J impact energy. Absorbed energy, penetration, impact load and damage morphology were obtained. The impact energy was efficiently absorbed by the material. Both aluminum alloy layers underwent plastic deformation whereas the fiber layer failed. A macroscopic cross-sectional morphology was presented using the FE model. An agreement between the numerical and the experiment results were achieved and discussed.

Three-dimensional simulation of the near-fault ground motion for the 1995 Hyogo-Ken Nanbu (Kobe), Japan, earthquake

1998 ◽  
Vol 88 (2) ◽  
pp. 428-440 ◽  
Author(s):  
Arben Pitarka ◽  
Kojiro Irikura ◽  
Tomotaka Iwata ◽  
Haruko Sekiguchi
Keyword(s):  
Ground Motion ◽  
Velocity Structure ◽  
Ground Motions ◽  
Three Dimensional ◽  
High Amplitude ◽  
Near Fault ◽  
Basin Edge ◽  
Dimensional Simulation ◽  
Near Fault Ground Motion ◽  
East West

Abstract The 17 January 1995 Hyogo-ken Nanbu earthquake is a typical example showing that the ground motions along basin-edge faults can be very destructive. In this study, we simulate the near-fault ground motion from this earthquake based on a kinematic fault model and a simplified 3D velocity structure of the Kobe area. The kinematic earthquake rupture and the wave propagation are modeled using a 3D finite-difference method (FDM). Our simulation identifies the basin-edge effect as an important factor that influenced the ground-motion amplification pattern in the Kobe area. We found that the coupling of the source directivity and basin-edge effects causes impulsive ground motions with extremely high amplitude at periods greater than 1 sec and in a narrow zone offset less than 1 km from the basin edge. The combination of these effects acted to create a fairly continuous band of amplification that extends about 30 km in an elongated zone parallel to the basin-edge boundary. In some areas, localized site effects might have been as important as the abovementioned effects, but they cannot explain the continuity of the extended east-west zone of damage.

scholarly journals Safety Analysis of the Running Train under Earthquake Dynamic Disturbance

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Mingfei Li ◽  
Junwei Liu
Keyword(s):  
Dynamic Response ◽  
Ground Motion ◽  
Seismic Waves ◽  
Artificial Boundary ◽  
Wave Source ◽  
Dynamic Disturbance ◽  
Seismic Input ◽  
The Impact ◽  
Track Slab ◽  
Wheel Track

Focusing on the safe operation of rail transit during earthquakes, the finite element method is used to construct a wheel-track-subgrade dynamics model in this study. Through spring-damper units, the relationship between the rail and the track slab and the connection between the track slab and the subgrade are established. A method for establishing a viscoelastic artificial boundary is proposed. Four seismic waves—the Tianjin wave, the El Centro wave, the Taft wave, and the Qian’an wave—are selected as the seismic input waveforms, and only the impact of the lateral ground motion on the wheel-track-subgrade system is considered. In this paper, the ground motion problem is transformed into a wave source problem, the seismic input is transformed into an equivalent load acting on the artificial boundary, and the wave input of the viscoelastic artificial boundary is realized. The normalization method is used to process the seismic waves, and a method that converts the input of the seismic waves into equivalent loads is proposed. The changing laws of different dynamic response indexes under the influence of the four waveforms are studied. Under the action of the Tianjin wave, the wheel-rail dynamic response is very violent near the acceleration peak, whereas, after the peak, all dynamic response indexes are within a safe range. Under the effect of the El Centro wave, the collision between the wheel and the track is relatively violent, and the train is already in a dangerous state. Under the action of the Taft wave, due to the sudden action of the peak ground motion acceleration, the displacement between the wheel and the track increases instantaneously, causing the train to derail. Under the action of the Qian’an wave, the force between the wheel and rail changes approximately linearly with respect to the frequency of the ground motion, and all dynamic response indexes are within a safe range. The vibration intensity of the four seismic waves is amplified by an intensity expansion factor. Except for the Tianjin wave, the amplified seismic wave has a greater impact on safe train operations. This paper can provide a reference for research on the running safety of trains under similar dynamic disturbance conditions.

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