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Seismic response and correlation analysis of a pile-supported wharf to near-fault pulse-like ground motions
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作者 Wang Jianfeng Su Lei +2 位作者 Xie Libo Ling Xianzhang Ju Peng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第4期883-897,共15页
Earthquake investigations have shown that near-fault pulse-like(NF-P)ground motions have unique characteristics compared to near-fault non-pulse-like(NF-NP)and far-field(FF)ground motions.It is necessary to study the ... Earthquake investigations have shown that near-fault pulse-like(NF-P)ground motions have unique characteristics compared to near-fault non-pulse-like(NF-NP)and far-field(FF)ground motions.It is necessary to study the seismic response of pile-supported wharf(PSW)structures under NF-P ground motions.In this study,a three-dimensional finite element numerical model is created to simulate a PSW.By imparting three types of ground motion,the engineering demand parameters(EDPs)of PSW under NF-P ground motions were analyzed and compared,in which EDPs are the maximum displacement and bending moment of the piles.Twenty intensity measures(IMs)were selected to characterize the properties of ground motions.The correlation between IMs and EDPs was explored.The results show that the piles present larger displacement and bending moment under NF-P ground motions compared to NF-NP and FF ground motions.None of the IMs have a high correlation with EDPs under NF-P ground motions,and these IMs are more applicable to FF ground motions.The correlation coefficients between EDPs and IMs under three types of ground motion were obtained,which will provide a valuable reference for the seismic design of PSWs. 展开更多
关键词 pile-supported wharf correlation analysis near-fault pulse-like ground motion intensity measure seismic response
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Dynamic characteristics of coal specimens with varying static preloading levels under low-frequency disturbance load
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作者 WEN Xiao-ze FENG Guo-rui +5 位作者 GUO Jun YU Lu-yang QIAN Rui-peng ZHANG Jie ZHANG Peng-fei FENG Wen-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2644-2657,共14页
The mechanical properties of residual coal pillars under the influence of upward mining disturbances significantly affect the safety of residual mining activities on working faces.This study conducted low-frequency di... The mechanical properties of residual coal pillars under the influence of upward mining disturbances significantly affect the safety of residual mining activities on working faces.This study conducted low-frequency disturbance dynamic uniaxial compression tests on coal specimens using a self-developed dynamic-static load coupling electro-hydraulic servo system,and studied the strength evolutions,surface deformations,acoustic emission(AE)characteristic parameters,and the failure modes of coal specimens with different static preloading levels were studied.The disturbance damage is positively correlated with the coal specimen static preload level.Specifically,the cumulative AE count rates of the initial accelerated damage stage for the coal specimens with static preloading level of 60%and 70%of the uniaxial compressive strength(UCS)were 2.66 and 3.19 times that of the 50%UCS specimens,respectively.Macroscopically,this behaviour manifested as a decrease in the compressive strength,and the mean strengths of the disturbance-damaged coal specimens with 60%and 70%of UCS static preloading decreased by 8.53%and 9.32%,respectively,compared to those of the specimens under pure static loading.The crack sources,such as the primary fissures,strongly control the dynamic response of the coal specimen.The difference between the dynamic responses of the coal specimens and that of dense rocks is significant. 展开更多
关键词 low-frequency disturbance dynamic response coal specimens static preloading level
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Analysis of Wave Added Drag and Motion Response of Mid-high-speed Ship against Waves
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作者 Jing Wang Yu Zhou 《Sustainable Marine Structures》 2023年第1期1-10,共10页
In order to accurately predict the on-wave resistance and responses to hull motions of ships in actual sea conditions,the k-εmethod of the RNG model is adopted on the basis of the unsteady RANS method.The two-formula... In order to accurately predict the on-wave resistance and responses to hull motions of ships in actual sea conditions,the k-εmethod of the RNG model is adopted on the basis of the unsteady RANS method.The two-formula turbulence model deals with the viscous flow,the VOF method captures the free surface,the velocity boundary method makes waves,the artificial damping method is used to eliminate waves,and the nested grid technology is used to deal with the motion response of ships on waves.Combined with the 6-DOF motion formula,a three-dimensional numerical wave cell for regular waves is established.For one example,taking a KCS Container ship and fishing boat sailing at a mid-high-speed,the increase of wave resistance and motion response at different wavelengths are analyzed,and the simulation results are compared with the experimental value,the content of strip theory in potential flow theory and the panel method to prove the reliability of CFD method in predicting ship motion. 展开更多
关键词 CFD method Wave added resistance motion response Numerical pool Numerical simulation
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Molecular mechanisms and roles of inflammatory responses on low-frequency residual hearing after cochlear implantation 被引量:1
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作者 Juanjuan Gao Haijin Yi 《Journal of Otology》 CSCD 2022年第1期54-58,共5页
Preservation of low-frequency residual hearing is very important for combined electro-acoustic stimulation after cochlear implantation.However,in clinical practice,loss of low-frequency residual hearing often occurs a... Preservation of low-frequency residual hearing is very important for combined electro-acoustic stimulation after cochlear implantation.However,in clinical practice,loss of low-frequency residual hearing often occurs after cochlear implantation and its mechanisms remain unclear.Factors affecting lowfrequency residual hearing after cochlear implantation are one of the hot spots in current research.Inflammation induced by injury associated with cochlear implantation is deemed to be significant,as it may give rise to low-frequency residual hearing loss by interfering with the blood labyrinth barrier and neural synapses.Pathological changes along the pathway for low-frequency auditory signals transmission may include latent factors such as damage to neuroepithelial structures,synapses,stria vascularis and other ultrastructures.In this review,current research on mechanisms of low-frequency residual hearing loss after cochlear implantation and possible roles of inflammatory responses are summarized. 展开更多
关键词 low-frequency residual hearing loss Cochlear implantation Electro-acoustic stimulation(EAS) Inflammatory response Blood labyrinth barrier(BLB)
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Influence of Total Ionizing Dose Irradiation on Low-Frequency Noise Responses in Partially Depleted SOI nMOSFETs
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作者 彭超 恩云飞 +3 位作者 雷志锋 陈义强 刘远 李斌 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第11期106-109,共4页
Total ionizing dose effect induced low frequency degradations in 130nm partially depleted silicon-on-insulator (SOI) technology are studied by ^60Co γ -ray irradiation. The experimental results show that the flick... Total ionizing dose effect induced low frequency degradations in 130nm partially depleted silicon-on-insulator (SOI) technology are studied by ^60Co γ -ray irradiation. The experimental results show that the flicker noise at the front gate is not affected by the radiation since the radiation induced trapped charge in the thin gate oxide can be ignored. However, both the Lorenz spectrum noise, which is related to the linear kink effect (LKE) at the front gate, and the flicker noise at the back gate are sensitive to radiation. The radiation induced trapped charge in shallow trench isolation and the buried oxide can deplete the nearby body region and can activate the traps which reside in the depletion region. These traps act as a GR center and accelerate the consumption of the accumulated holes in the floating body. It results in the attenuation of the LKE and the increase of the Lorenz spectrum noise. Simultaneously, the radiation induced trapped charge in the buried oxide can directly lead to an enhanced flicker noise at the back gate. The trapped charge density in the buried oxide is extracted to increase from 2.21×10^18 eV^-1 cm^-3 to 3.59×10^18?eV^-1 cm^-3 after irradiation. 展开更多
关键词 SOI MOSFET Influence of Total Ionizing Dose Irradiation on low-frequency Noise responses in Partially Depleted SOI nMOSFETs
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An extended multiple-support response spectrum method incorporating fluid-structure interaction for seismic analysis of deep-water bridges 被引量:1
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作者 Wu Kun Li Ning Li Zhongxian 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第1期211-223,共13页
The effects of ground motion spatial variability(GMSV)or fluid-structure interaction(FSI)on the seismic responses of deep-water bridges have been extensively examined.However,there are few studies on the seismic perfo... The effects of ground motion spatial variability(GMSV)or fluid-structure interaction(FSI)on the seismic responses of deep-water bridges have been extensively examined.However,there are few studies on the seismic performance of bridges considering GMSV and FSI effects simultaneously.In this study,the original multiple-support response spectrum(MSRS)method is extended to consider FSI effect for seismic analysis of deep-water bridges.The solution of hydrodynamic pressure on a pier is obtained using the radiation wave theory,and the FSI-MSRS formulation is derived according to the random vibration theory.The influence of FSI effect on the related coefficients is analyzed.A five-span steel-concrete continuous beam bridge is adopted to conduct the numerical simulations.Different load conditions are designed to investigate the variation of the bridge responses when considering the GMSV and FSI effects.The results indicate that the incoherence effect and wave passage effect decrease the bridge responses with a maximum percentage of 86%,while the FSI effect increases the responses with a maximum percentage of 26%.The GMSV and FSI effects should be included in the seismic design of deep-water bridges. 展开更多
关键词 response spectrum method seismic response of bridge ground motion spatial variability fluid-structure interaction rdiation wave theory
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Time-frequency response spectrum of rotational ground motion and its application 被引量:16
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作者 Wei Che Qifeng Luo 《Earthquake Science》 CSCD 2010年第1期71-77,共7页
The rotational seismic motions are estimated from one station records of the 1999 Jiji (Chi-Chi), Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum (TFRS... The rotational seismic motions are estimated from one station records of the 1999 Jiji (Chi-Chi), Taiwan, earthquake based on the theory of elastic plane wave propagation. The time-frequency response spectrum (TFRS) of the rotational motions is calculated and its characteristics are analyzed, then the TFRS is applied to analyze the damage mechanism of one twelve-storey frame concrete structure. The results show that one of the ground motion components can not reflect the characteristics of the seismic motions completely; the characteristics of each component, especially rotational motions, need to be studied. The damage line of the structure and TFRS of ground motion are important for seismic design, only the TFRS of input seismic wave is suitable, the structure design is reliable. 展开更多
关键词 Jiji (Chi-Chi) earthquake ground motion rotational component time-frequency response spectrum damage line
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An investigation of the influence of near-fault ground motion parameters on the pile's response in liquefiable soil 被引量:7
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作者 Hui Shuqing Tang Liang +3 位作者 Zhang Xiaoyu Wang Youqing Ling Xianzhang Xu Bowen 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2018年第4期729-745,共17页
The performance of a soil-pile system can be significantly influenced by ground motion parameters. However, few research efforts have been performed to provide a complete description of the influence of key ground mot... The performance of a soil-pile system can be significantly influenced by ground motion parameters. However, few research efforts have been performed to provide a complete description of the influence of key ground motion parameters on the pile’s behavior in liquefiable soil. In this study, a three-dimensional finite element(FE) model, incorporating a multisurface plasticity solid-fluid fully coupled formulation soil constitutive model, is developed and calibrated based on centrifuge test data. Seventy-two near-fault non-pulse-like(NF-NP) and seventy-two near-fault pulse-like(NF-P) ground motion records are studied with the calibrated FE model to distinguish the effects of several common ground motion parameters soon afterwards. Base on the parametric study results, a simple index, RPGV/PGA(i.e., the ratio of peak ground velocity(PGV) to peak ground acceleration(PGA)), shows its capability on characterizing the pile behavior under both NF-NP and NF-P ground motions. Furthermore, two equations are developed to characterize the relationships between the RPGV/PGA as well as the maximum pile’s moments and displacements. In general, this study can be helpful to gain new insights on the influence of typical index parameters for near-field ground motions on the response of the pile foundation in liquefiable soil. 展开更多
关键词 seismic response predictive equations near-fault ground motion pile foundation LIQUEFACTION
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Artificial ground motion compatible with specified ground shaking peaks and target response spectrum 被引量:6
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作者 赵凤新 张郁山 吕红山 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2006年第1期41-48,共8页
This article describes a hybrid simulation method to generate artificial ground motion time histories that are compatible with specified peak seismic acceleration, velocity and displacement as well as the target respo... This article describes a hybrid simulation method to generate artificial ground motion time histories that are compatible with specified peak seismic acceleration, velocity and displacement as well as the target response spectrum of absolute acceleration. First, based on traditional methods that match the target spectrum in the frequency domain, an initial acceleration time history was synthesized to satisfy the specified peak acceleration, target spectral acceleration and intensity envelope. Second, by using the inversion formula of the seismic input to a linear single-degree-of-freedom system and by superimposing a series of narrow-band time histories in the time domain, the initial time history is further modified to allow its peak velocity and displacement to approach the targets and improve its matching precision with the target spectrum. Numerical examples are provided to demonstrate that the proposed method achieves good agreement with the target values. 展开更多
关键词 artificial ground motion acceleration response spectrum ground shaking peaks spectrum matching
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Dynamic Responses of Top Tensioned Riser Under Combined Excitation of Internal Solitary Wave, Surface Wave and Vessel Motion 被引量:11
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作者 GUO Haiyan ZHANG Li +1 位作者 LI Xiaomin LOU Min 《Journal of Ocean University of China》 SCIE CAS 2013年第1期6-12,共7页
An investigation on the dynamic response of a top tensioned riser (TTR) under combined excitation of internal solitary wave, surface wave and vessel motion is presented in this paper. The riser is idealized as a ten... An investigation on the dynamic response of a top tensioned riser (TTR) under combined excitation of internal solitary wave, surface wave and vessel motion is presented in this paper. The riser is idealized as a tensioned slender beam with dynamic boundary conditions. The KdV-mKdV equation is chosen to simulate the internal solitary wave, and the vessel motion is analysed by using the method proposed by Sexton. Using finite element method, the governing equation is solved in time domain with Newmark-13 method. The computation programs for solving the differential equations in time domain are compiled and numerical results are obtained, including dimensionless displacement and stress. The action of internal solitary wave on the riser is like a slow powerful impact, and is much larger than those of surface wave and vessel motion. When the riser is under combined excitation, it vibrates at frequencies of both surface wave and vessel motion, and the vibration is dominated by internal solitary wave. As the internal solitary wave crest passes by the centre of the riser, the maximum displacement and stress along the riser occur. Compared to the lower part, the displacement and stress of the riser in the upper part are much larger. 展开更多
关键词 dynamic response TTR internal solitary wave surface wave vessel motion
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Engineering characteristics of near-fault vertical ground motions and their effect on the seismic response of bridges 被引量:3
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作者 李新乐 窦慧娟 朱晞 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2007年第4期345-350,共6页
A wide variety of near-fault strong ground motion records were collected from various tectonic environments worldwide and were used to study the peak value ratio and response spectrum ratio of the vertical to horizont... A wide variety of near-fault strong ground motion records were collected from various tectonic environments worldwide and were used to study the peak value ratio and response spectrum ratio of the vertical to horizontal component of ground motion, focusing on the effect of earthquake magnitude, site conditions, pulse duration, and statistical component. The results show that both the peak value ratio and response spectrum ratio are larger than the 2/3 value prescribed in existing seismic codes, and the relationship between the vertical and horizontal ground motions is comparatively intricate. In addition, the effect of the near-fault ground motions on bridge performance is analyzed, considering both the material nonlinear characteristics and the P-A effect. 展开更多
关键词 near-fault vertical ground motion peak value ratio spectrum ratio BRIDGE seismic response
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Orthogonal expansion of ground motion and PDEM-based seismic response analysis of nonlinear structures 被引量:2
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作者 Li Jie Liu Zhangjun Chen Jianbing 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2009年第3期313-328,共16页
This paper introduces an orthogonal expansion method for general stochastic processes. In the method, a normalized orthogonal function of time variable t is first introduced to carry out the decomposition of a stochas... This paper introduces an orthogonal expansion method for general stochastic processes. In the method, a normalized orthogonal function of time variable t is first introduced to carry out the decomposition of a stochastic process and then a correlated matrix decomposition technique, which transforms a correlated random vector into a vector of standard uncorrelated random variables, is used to complete a double orthogonal decomposition of the stochastic processes. Considering the relationship between the Hartley transform and Fourier transform of a real-valued function, it is suggested that the first orthogonal expansion in the above process is carried out using the Hartley basis function instead of the trigonometric basis function in practical applications. The seismic ground motion is investigated using the above method. In order to capture the main probabilistic characteristics of the seismic ground motion, it is proposed to directly carry out the orthogonal expansion of the seismic displacements. The case study shows that the proposed method is feasible to represent the seismic ground motion with only a few random variables. In the second part of the paper, the probability density evolution method (PDEM) is employed to study the stochastic response of nonlinear structures subjected to earthquake excitations. In the PDEM, a completely uncoupled one-dimensional partial differential equation, the generalized density evolution equation, plays a central role in governing the stochastic seismic responses of the nonlinear structure. The solution to this equation will yield the instantaneous probability density function of the responses. Computational algorithms to solve the probability density evolution equation are described. An example, which deals with a nonlinear frame structure subjected to stochastic ground motions, is illustrated to validate the above approach. 展开更多
关键词 seismic ground motion stochastic processes orthogonal expansion probability density evolution method nonlinear structures stochastic response analysis
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Motion and Dynamic Responses of A Semisubmersible in Freak Waves 被引量:1
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作者 LI Xin DENG Yan-fei +2 位作者 LI Lei TIAN Xin-liang LI Jun 《China Ocean Engineering》 SCIE EI CSCD 2017年第6期754-763,共10页
The present research aims at clarifying the effects of freak wave on the motion and dynamic responses of a semisubmersible. To reveal the effects of mooring stiffness, two mooring systems were employed in the model te... The present research aims at clarifying the effects of freak wave on the motion and dynamic responses of a semisubmersible. To reveal the effects of mooring stiffness, two mooring systems were employed in the model tests and time-domain simulations. The 6-DOF motion responses and mooring tensions have been measured and the 3- DOF motions of fairleads were calculated as well. From the time series, trajectories and statistics information, the interactions between the freak wave and the semisubmersible have been demonstrated and the effects of mooring stiffness have been identified. The shortage of numerical simulations based on 3D potential flow theory is presented. Results show that the freak wave is likely to cause large horizontal motions for soft mooring system and to result in extremely large mooring tensions for tight mooring system. Therefore, the freak wave is a real threat for the marine structure, which needs to be carefully considered at design stage. 展开更多
关键词 motion response mooring tension semisubmersible freak wave mooring stiffness
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Dynamic-Response Analysis of the Branch System of a Utility Tunnel Subjected to Near-Fault and Far-Field Ground Motions in Different Input Mechanisms 被引量:2
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作者 Yuhang Jin Endong Guo +1 位作者 Houli Wu Peilei Yan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第1期167-186,共20页
There are few studies on the dynamic-response mechanism of near-fault and far-field ground motions for large underground structures,especially for the branch joint of a utility tunnel(UT)and its internal pipeline.Base... There are few studies on the dynamic-response mechanism of near-fault and far-field ground motions for large underground structures,especially for the branch joint of a utility tunnel(UT)and its internal pipeline.Based on the theory of a 3D viscous-spring artificial boundary,this paper deduced the equivalent nodal force when a P wave and an SV wave were vertically incident at the same time and transformed the ground motion into an equivalent nodal force using a self-developed MATLAB program,which was applied to an ABAQUS finite element model.Based on near-fault and far-field groundmotions obtained fromtheNGA-WEST2 database,the dynamic responses of a utility tunnel and its internal pipeline in different inputmechanisms of near-fault and far-field groundmotions were compared according to bidirectional input and tridirectional input,respectively.Generally,the damage to the utility tunnel caused by the near-fault ground motion was stronger than that caused by the far-field ground motion,and the vertical ground motion of near-fault ground motion aggravated the damage to the utility tunnel.In addition,the joint dislocation of the upper and lower three-way joints of the pipeline in the branch systemunder the seismic action led to local stress concentrations.In general,the branch system of the utility tunnel had good seismic performance to resist the designed earthquake action and protect the internal pipeline fromdamage during the rare earthquake. 展开更多
关键词 Dynamic response utility tunnel near-fault ground motion far-field ground motion earthquake input seismic design
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A study on amplification response of soil ground motion in Shanghai using strong motion records 被引量:1
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作者 徐永林 熊里军 +1 位作者 章纯 赵志光 《Acta Seismologica Sinica(English Edition)》 CSCD 2002年第6期691-695,共5页
关键词 soil ground motion amplification response soil layers INTENSITY
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A Method for Calculation of Low-Frequency Slow Drift Motions Based on NURBS for Floating Bodies 被引量:2
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作者 刘文玺 任慧龙 《China Ocean Engineering》 SCIE EI 2009年第3期399-414,共16页
Through a higher-order boundary element method based on NURBS (Non-uniform Rational B-splines), the calculation of second-order low-frequency forces and slow drift motions is conducted for floating bodies. In the fl... Through a higher-order boundary element method based on NURBS (Non-uniform Rational B-splines), the calculation of second-order low-frequency forces and slow drift motions is conducted for floating bodies. In the floating body's inner domain, an auxiliary equation is obtained by applying a Green function which satisfies the solid surface condition. Then, the auxiliary equation and the velocity potential equation are combined in the fluid domain to remove the solid angle coefficient and the singularity of the double layer potentials in the integral equation. Thus, a new velocity potential integral equation is obtained. The new equation is extended to the inner domain to reheve the irregular frequency effects; on the basis of the order analysis, the comparison is made about the contribution of all integral terms with the result in the second-order tow-frequency problem; the higher-order boundary element method based on NURBS is apphed to calculate the geometric position and velocity potentials; the slow drift motions are calculated by the spectrum analysis method. Removing the solid angle coefficient can apply NURBS technology to the hydrodynamic calculation of floating bodies with complex surfaces, and the extended boundary integral method can reduce the irregular frequency effects. Order analysis shows that free surface integral can be neglected, and the numerical results can also prove the correctness of order analysis. The results of second-order low-frequency forces and slow drift motions and the comparison with the results from references show that the application of the NURBS technology to the second-order low-frequency problem is of high efficiency and credible results. 展开更多
关键词 splines higher-order boundary element method second-order low-frequency force slow drift motions irregular frequencies spectrum analysis order analysis
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Study on the effect of ground motion direction on the response of engineering structure 被引量:1
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作者 Sun Menghan Fan Feng +1 位作者 Sun Baitao Zhi Xudong 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2016年第4期649-656,共8页
Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on... Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW (East -West) direction, NS (South- North) direction and perpendicular to the surface (z) direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations: (1) the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; (2) response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and (3) the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage to structures following earthquakes and explaining the seismic damage. Meanwhile, it also provides a reference value for research into the most severe ground motion. 展开更多
关键词 direction of grotmd motion structure effect coordinate transformation response spectrum
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Spiral piezoelectric transducer in torsional motion as low-frequency power harvester 被引量:1
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作者 王海仁 胡洪平 +1 位作者 杨嘉实 胡元太 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2013年第5期589-596,共8页
A structure consisting of a spiral piezoelectric transducer and a concentrated mass is proposed as a low-frequency piezoelectric power harvester. A theoretical model is developed for the system from the theory of piez... A structure consisting of a spiral piezoelectric transducer and a concentrated mass is proposed as a low-frequency piezoelectric power harvester. A theoretical model is developed for the system from the theory of piezoelectricity. An analysis is performed to demonstrate the low-frequency nature of the system. Other basic characteristics of the power harvester including the output power, voltage, and efficiency are also calculated and examined. 展开更多
关键词 PIEZOELECTRIC torsional motion low-frequency power harvester
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Vertical-to-horizontal response spectral ratio for offshore ground motions:Analysis and simplified design equation 被引量:12
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作者 陈宝魁 王东升 +2 位作者 李宏男 孙治国 李超 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第1期203-216,共14页
In order to study the differences in vertical component between onshore and offshore motions,the vertical-to-horizontal peak ground acceleration ratio(V/H PGA ratio) and vertical-to-horizontal response spectral ratio(... In order to study the differences in vertical component between onshore and offshore motions,the vertical-to-horizontal peak ground acceleration ratio(V/H PGA ratio) and vertical-to-horizontal response spectral ratio(V/H) were investigated using the ground motion recordings from the K-NET network and the seafloor earthquake measuring system(SEMS).The results indicate that the vertical component of offshore motions is lower than that of onshore motions.The V/H PGA ratio of acceleration time histories at offshore stations is about 50%of the ratio at onshore stations.The V/H for offshore ground motions is lower than that for onshore motions,especially for periods less than 0.8 s.Furthermore,based on the results in statistical analysis for offshore recordings in the K-NET,the simplified V/H design equations for offshore motions in minor and moderate earthquakes are proposed for seismic analysis of offshore structures. 展开更多
关键词 offshore ground motion vertical component simplified design equation vertical-to-horizontal response spectral ratio (V/H) vertical-to-horizontal peak ground acceleration ratio (V/H PGA ratio) K-NET network seafloor earthquake measuring system (SEMS)
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Seismic Responses of Asymmetric Base-Isolated Structures under Near-Fault Ground Motion 被引量:1
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作者 叶昆 李黎 方秦汉 《Journal of Southwest Jiaotong University(English Edition)》 2008年第4期335-345,共11页
An inter-story shear model of asymmetric base-isolated structures incorporating deformation of each isolation bearing was built, and a method to simultaneously simulate bi-directional near-fault and far-field ground m... An inter-story shear model of asymmetric base-isolated structures incorporating deformation of each isolation bearing was built, and a method to simultaneously simulate bi-directional near-fault and far-field ground motions was proposed. A comparative study on the dynamic responses of asymmetric base-isolated structures under near-fault and far-field ground motions were conducted to investigate the effects of eccentricity in the isolation system and in the superstructures, the ratio of the uncoupled torsional to lateral frequency of the superstructure and the pulse period of near-fault ground motions on the nonlinear seismic response of asymmetric base-isolated structures. Numerical results show that eccentricity in the isolation system makes asymmetric base-isolated structure more sensitive to near-fault ground motions, and the pulse period of near-fault ground motions plays an import role in governing the seismic responses of asymmetric base-isolated structures. 展开更多
关键词 Asymmetric base-isolated structure Near-fault ground motion Far-field ground motion Nonlinear seismic response
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