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Dynamic and electrical responses of a curved sandwich beam with glass reinforced laminate layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact
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作者 N.SHAHVEISI S.FELI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第1期155-178,共24页
The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigate... The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigated.The current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial velocity.For the layer analysis,the high-order shear deformation theory(HSDT)and Frostig's second model for the displacement fields of the core layer are used.The classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of time.In order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the LVI.Finite element(FE)simulations are conducted by means of the ABAQUS software.The effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed. 展开更多
关键词 analytical model piezoelectric layer curved sandwich beam glass reinforced laminate(GRL) pliable core low-velocity impact(LVI) classical non-adhesive elastic contact theory
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Preliminary analysis for the roles of crustal low-velocity and high-conductivity body in process of strong earthquake preparation 被引量:3
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作者 李炳乾 牛志仁 段锋 《Acta Seismologica Sinica(English Edition)》 CSCD 2000年第2期151-158,共8页
In this paper, the roles of low velocity and high conductivity body inside the crust in the process of strong earth quake preparation are approached by using theoretical analysis method based on the comprehensive rese... In this paper, the roles of low velocity and high conductivity body inside the crust in the process of strong earth quake preparation are approached by using theoretical analysis method based on the comprehensive researches on the fine structure of strong seismic source in the North China. The following results are obtained. The low-velocity and high-conductivity body plays the promoting role for the action of deep-seated structure in the medium stage of earthquake preparation, except that its existence is advantageous to the stress concentrating in the overlying brittle layer during the process of earthquake preparation. And it plays the triggering role for the occurrence of strong earthquake in the later stage of earthquake preparation. 展开更多
关键词 low-velocity and high-conductivity body strong earthquake preparation promoting function triggering function
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Characteristics of head wave in multi-layered half-space
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作者 张坚 张海明 陈晓非 《Acta Seismologica Sinica(English Edition)》 CSCD 2002年第6期585-594,共10页
In this article, we analyze the dynamic characteristics of head wave in multi-layered half-space media models with high-velocity layer or low-velocity layer, and the model with a continuous transition-zone between the... In this article, we analyze the dynamic characteristics of head wave in multi-layered half-space media models with high-velocity layer or low-velocity layer, and the model with a continuous transition-zone between the crust and the mantle by using synthetic seismogram. It is concluded that the dynamic characteristics of head wave are sensitive to the thickness and velocity of the high-velocity layer. There is obvious diffraction phenomenon of seismic wave if the thickness of high-velocity layer is very small compared with the characteristic wavelength. In this case, the high-velocity layer cannot shield the head wave propagating along the upper interface of the media below it, and the amplitude of this head wave is proportional to the thickness or the velocity of the high-velocity layer. When the thickness of high-velocity layer is nearly identical to the characteristic wavelength of seismic wave, the wave phases reflected from the bottom of the high-velocity layer and the head wave phase may have very close arrival and weaken each other because of destructive interference. As to low-velocity layer, the amplitude of the head wave is weak and decreases with the velocity of this layer. It is also found that if a continuous transition-zone between the crust and the mantle is introduced, we can get a strong apparent head wave phase in synthetic seismogram and the amplitude of this phase increases with the thickness or velocity gradient of the transition-zone. 展开更多
关键词 synthetic seismogram head wave high-velocity layer low-velocity layer transition-zone be-tween crust and mantle
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On the physical model of earthquake precursor fields and the mechanism of precursors'timespace distribution──origin and evidences of the strong body earthquake──generating model 被引量:16
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作者 梅世蓉 《Acta Seismologica Sinica(English Edition)》 CSCD 1995年第3期337-349,共13页
According to the requirement of the project 'Establishment of the Physical Model of Earthquake PrecursorFields',this paper elucidates the train of thinking for research on the project and some scientific probl... According to the requirement of the project 'Establishment of the Physical Model of Earthquake PrecursorFields',this paper elucidates the train of thinking for research on the project and some scientific problems whichmust be studied i, the elucidation emphasizes that the core of this project is to study the conditions and processesof the generation of strong earthquakes. The paper first outlines the origin and development of the'strong-bodyearthquake-generating model' proposed by the author in the 1980;and then proves the reasonableness of themodel from three aspects, namely: deep structures, mechanical analysis and rock fracture experiments. Bystudying the tomographic image for the northern part of North China, it can be seen that the sources of strongearthquakes are all distributed in high-velocity bodies,or in the contact zone between high-velocity and lowvelocity bodies but nearer to the high-velocity body. It has been affirmed through studies of the mechanical modelsof hard and soft inclusions that the existence of a hard inclusion is an imPOrtant condition for the high concentration of large amounts of strain energy. A lot of theoretical and experimental studies have been made to investigate the conditions for rock instability; the results have consistently indicated that rock instability,sudden fracture and stress drop would be possible only if the stiffness of the source body is greater than the environmentalstiffness. 展开更多
关键词 inclusion theory pattern strong-body pattern stress concentration layered block structure highand low-velocity body fracture instability
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Electrical Structure and Fault Features of Crust and Upper Mantle beneath the Western Margin of the Qinghai-Tibet Plateau:Evidence from the Magnetotelluric Survey along Zhada-Quanshui Lake Profile 被引量:3
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作者 金胜 叶高峰 +2 位作者 魏文博 邓明 景建恩 《Journal of China University of Geosciences》 SCIE CSCD 2007年第4期326-333,共8页
The magnetotelluric (MT) survey along the Zhada (札达)-Quanshui (泉水) Lake profile on the western margin of the Qinghai (青海)-Tibet plateau shows that the study area is divided into three tectonic provinces ... The magnetotelluric (MT) survey along the Zhada (札达)-Quanshui (泉水) Lake profile on the western margin of the Qinghai (青海)-Tibet plateau shows that the study area is divided into three tectonic provinces by the Yalung Tsangpo and Bangong (班公)-Nujiang (怒江) sutures. From south to north these are the Himalayan terrane, Gangdise terrane, and Qiangtang (羌塘) terrane. For the study area, there are widespread high-conductivity layers in the mid and lower crust, the top layers of which fluctuate intensively. The high-conductivity layer within the Gangdise terrane is deeper than those within the Qiangtang terrane and the Himalaya terrane, and the deepest high-conductivity layer is to the south of the Bangong-Nujiang suture. The top surface of the high-conductivity layer in the south of the Bangong-Nujiang suture is about 20 km lower than that in the north of it. The high-conductivity layer within the Gangdise terrane dips toward north and there are two high-conductivity layers within the crust of the southern Qiangtang terrane. In the upper crust along the profile, there are groups of lateral electrical gradient zones or distortion zones of different scales and occurrence indicating the distribution of faults and sutures along the profile. According to the electrical structure, the structural characteristics and space distribution of the Yalung Tsangpo suture, Bangong.Nujiang suture, and the major faults of Longmucuo (龙木错) and Geerzangbu are inferred. 展开更多
关键词 west margin of Qinghai-Tibet plateau MT high-conductivity layers of crust electrical structure structural characteristics of fault.
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Study on the Electrical Conductivity of 0.025 mol NaCl Solution at 0.25-3.75 GPa and 20-370℃ 被引量:1
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作者 Zheng Haifei Xie Hongsen +2 位作者 Xu Yousheng Song Maoshuang Guo Jie and Zhang Yueming Earth’s Interior Material Laboratory,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,Guizhou 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1997年第3期273-281,共9页
The electrical conductance of 0.025 mol NaCl solution was measured at0.25-3.75 GPa and 20-370℃. As shown by the results, the conductance increases with temper-ature, and there is a liner relation between the reciproc... The electrical conductance of 0.025 mol NaCl solution was measured at0.25-3.75 GPa and 20-370℃. As shown by the results, the conductance increases with temper-ature, and there is a liner relation between the reciprocal of temperature and the logarithm ofthe conductance but their slopes are different at different pressures. The relations between theconductance and pressure is rather complex and there are some discontinuities: in the range of2.25-3.75 GPa, the conductance increases with the pressure; in the range of 1.25-2.0 GPa, theconductance is not related to the pressure; and at a pressure of 0.75 GPa, the conductance ishigher than that at the pressures nearby. This reflects that the NaCl solution has rather differentproperties of electronic chemistry at various pressures, and probably is an important cause forthe existence of the layers with high electrical conductance and low velocity in the Earth's crustand mantle. 展开更多
关键词 high T/ P NaCl solution electrical conductivity low-velocity and high-conductance layer
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Crustal S-wave velocity structure of the Yellowstone region using a seismic ambient noise method 被引量:2
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作者 Yan Lü Sidao Ni +3 位作者 Jun Xie Yingjie Xia Xiangfang Zeng Bin Liu 《Earthquake Science》 2013年第5期283-291,共9页
The Yellowstone volcano is one of the largest active volcanoes in the world, and its potential hazards demand detailed seismological and geodetic studies. Previous studies with travel time tomography and receiver func... The Yellowstone volcano is one of the largest active volcanoes in the world, and its potential hazards demand detailed seismological and geodetic studies. Previous studies with travel time tomography and receiver functions have revealed a low-velocity layer in the crust beneath the Yellowstone volcano, suggesting the presence of a magma chamber at depth. We use ambient seismic noise from regional seismic stations to retrieve short-period surface waves and then study the shallow shear velocity structure of the Yellowstone region by surface wave dispersion analysis. We first obtained a crustal model of the area outside of the Yellowstone volcano and then constructed an absolute shear wave velocity structure in combination with receiver function results for the crust beneath the Yellowstone volcano. The velocity model shows a low-velocity layer with shear velocity at around 1.3 km/s, suggesting that a large-scale magma chamber exists at shallow levels within the crust of the Yellowstone volcanic region. 展开更多
关键词 YELLOWSTONE Seismic ambient noise low-velocity layer
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The westward drift of the lithosphere:A tidal ratchet? 被引量:1
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作者 A.Carcaterra C.Doglioni 《Geoscience Frontiers》 SCIE CAS CSCD 2018年第2期403-414,共12页
Is the westerly rotation of the lithosphere an ephemeral accidental recent phenomenon or is it a stable process of Earth's geodynamics? The reason why the tidal drag has been questioned as the mechanism determinin... Is the westerly rotation of the lithosphere an ephemeral accidental recent phenomenon or is it a stable process of Earth's geodynamics? The reason why the tidal drag has been questioned as the mechanism determining the lithospheric shift relative to the underlying mantle is the apparent too high viscosity of the asthenosphere. However, plate boundaries asymmetries are a robust indication of the 'westerly'decoupling of the entire Earth's outer lithospheric shell and new studies support lower viscosities in the low-velocity layer(LVZ) atop the asthenosphere. Since the solid Earth tide oscillation is longer in one side relative to the other due to the contemporaneous Moon's revolution, we demonstrate that a non-linear rheological behavior is expected in the lithosphere mantle interplay. This may provide a sort of ratchet favoring lowering of the LVZ viscosity under shear, allowing decoupling in the LVZ and triggering the westerly motion of the lithosphere relative to the mantle. 展开更多
关键词 Westward drift of the LITHOSPHERE TECTONIC EQUATOR low-velocity layer ASTHENOSPHERE viscosity Non-linear rheology TIDAL RATCHET
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Earthquake-controlling Processes of Detachment Zones in Eastern North China 被引量:1
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作者 SUNAiqun NIUShuyin +2 位作者 SHAOJi'an HOUQuanlin ZHANGJianzhen 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第1期283-290,共8页
The basin-and-range area in eastern North China is known for frequent occurrence of earthquakes, their great magnitudes and heavy losses thereby incurred. Seismic studies in the past usually emphasized the intersectio... The basin-and-range area in eastern North China is known for frequent occurrence of earthquakes, their great magnitudes and heavy losses thereby incurred. Seismic studies in the past usually emphasized the intersections, inflexions and branches of the faults. However, the intensities of many great earthquakes in this area do not show linear distribution, and the epicenters are horizontally dispersed at certain depths instead of along the strike of faults. Based on the sub-mantle plume studies made by authors in the past decade, it is thought that there exists an uplifted sub-mantle plume under the fault depression area in North China. The uplifting and intrusion of mantle materials caused the upper crust to be faulted, while low-velocity and high-velocity layers are alternatively distributed in the middle crust under the influence of the mantle and the lower crust. The middle and lower crust materials were detached from the top of the sub-mantle plume to the surroundings while the sub-mantle plume materials were detached outward. When the detached middle and lower crust come to the boundary of fault basins in the upper crust, they will be obstructed by the orogenic zone and the detachment will go slower. The shearing between them will cause the stress to accumulate and release alternatively, so that earthquakes occurred frequently in the areas of sub-mantle plume and its surroundings. 展开更多
关键词 sub-mantle plume detachment belt earthquake-controlling structure low-velocity and high-conductivity zones north China basin-and range area
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Properties of wave velocity for two types of granitoids at high pressure and temperature and their geological meaning 被引量:2
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作者 杨树锋 陈汉林 +5 位作者 姜继双 竺国强 谢鸿森 侯渭 张月明 徐惠刚 《Science China Earth Sciences》 SCIE EI CAS 1997年第5期470-476,共7页
The wave velocity for two types of granitoids was measured using the analytic method of full-wave vibration at high pressure and high temperature. The laws of velocity changes for them differ with the pressure hoost a... The wave velocity for two types of granitoids was measured using the analytic method of full-wave vibration at high pressure and high temperature. The laws of velocity changes for them differ with the pressure hoost and temperature rise, and the velocity change of S-type is more violent than that of I-type. The 'softening point' of compressional wave velocity ( Vp) is also revealed during the measurement for two types of granitoids imitating the pressure and temperature at a certain depth. But the depth of 'softening', Vp after 'softening' and the percentage of Vp' s drop around the 'softening point' for two types of granitoids are obviously different. The depth of 'softening' is 15 km approximately and Vp after 'softening' is 5. 62 km/s for S-type granitoid. But for I-type granitoid the depth of 'softening' is 26 km approximately and Vp after 'softening' is 6. 08 km/s. Through careful analysis of rock slices after the experiment, it was found that the 'softening' of elastic-wave velocity is caused by the partial melting of granite. Combined with the results of geophysical prospecting, these results suggest that the low-velocity layers developing in the interior of Earth crust are related to the partial melting of different types of granitoids. The formation of the low-velocity layer in the upper-middle Earth crust is closely related to the development of S-type granitoid, but that in the lower Earth crust is closely related to the development of I-type granitoid. 展开更多
关键词 I-TYPE GRANITOID S-TYPE GRANITOID wave VELOCITY low-velocity layer
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VELOCITY STRUCTURE OF THE CRUST AND UPPER MANTLE IN THE COASTAL REGION OF SOUTH CHINA
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作者 廖其林 王振明 +2 位作者 王屏路 余兆康 黄向荣 《Chinese Science Bulletin》 SCIE EI CAS 1988年第17期1462-1465,共4页
Ⅰ. INTRODUCTION The coastal region of South China is located on the southeast tongue of Eurasian plate and borders on the Pacific plate in the east and on the Indian plate in the southwest. Having been driven by thre... Ⅰ. INTRODUCTION The coastal region of South China is located on the southeast tongue of Eurasian plate and borders on the Pacific plate in the east and on the Indian plate in the southwest. Having been driven by three plates, the crust and upper mantle 展开更多
关键词 deep SEISMIC SOUNDING (D.S.S.) VELOCITY structure low-velocity layer (LVL)
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