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Impact of Earthquake Action on the Design and Sizing of Jointed Masonry Structures in South Kivu, DRC
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作者 Edmond Dawak Fezeu Marcelline Blanche Manjia +3 位作者 Chérif Bishweka Biryondeke Patient Kubuya Binwa Élodie Rufine Zang Chrispin Pettang 《Open Journal of Civil Engineering》 2024年第1期127-153,共27页
This article deals with the investigation of the effects of seismic impacts on the design and dimensioning of structures in South Kivu. The starting point is the observation of an ambivalence that can be observed in t... This article deals with the investigation of the effects of seismic impacts on the design and dimensioning of structures in South Kivu. The starting point is the observation of an ambivalence that can be observed in the province, namely the non-consideration of seismic action in the study of structures by both professionals and researchers. The main objective of the study is to show the importance of dynamic analysis of structures in South Kivu. It adopts a meta-analytical approach referring to previous researches on South Kivu and proposes an efficient and optimal method. To arrive at the results, we use Eurocode 7 and 8. In addition, we conducted static analysis using the Coulomb method and dynamic analysis using the Mononobe-Okabe method and compared the results. At Nyabibwe, the results showed that we have a deviation of 24.47% for slip stability, 12.038% for overturning stability and 9.677% for stability against punching through a weight wall. 展开更多
关键词 jointed Masonry Weight-Bearing structures Seismic Action Eurocode 7 and 8 Static and Dynamic Analysis
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Joint inversion of gravity and vertical gradient data based on modified structural similarity index for the structural and petrophysical consistency constraint
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作者 Sheng Liu Xiangyun Wan +6 位作者 Shuanggen Jin Bin Jia Quan Lou Songbai Xuan Binbin Qin Yiju Tang Dali Sun 《Geodesy and Geodynamics》 EI CSCD 2023年第5期485-499,共15页
Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysica... Joint inversion is one of the most effective methods for reducing non-uniqueness for geophysical inversion.The current joint inversion methods can be divided into the structural consistency constraint and petrophysical consistency constraint methods,which are mutually independent.Currently,there is a need for joint inversion methods that can comprehensively consider the structural consistency constraints and petrophysical consistency constraints.This paper develops the structural similarity index(SSIM)as a new structural and petrophysical consistency constraint for the joint inversion of gravity and vertical gradient data.The SSIM constraint is in the form of a fraction,which may have analytical singularities.Therefore,converting the fractional form to the subtractive form can solve the problem of analytic singularity and finally form a modified structural consistency index of the joint inversion,which enhances the stability of the SSIM constraint applied to the joint inversion.Compared to the reconstructed results from the cross-gradient inversion,the proposed method presents good performance and stability.The SSIM algorithm is a new joint inversion method for petrophysical and structural constraints.It can promote the consistency of the recovered models from the distribution and the structure of the physical property values.Then,applications to synthetic data illustrate that the algorithm proposed in this paper can well process the synthetic data and acquire good reconstructed results. 展开更多
关键词 joint inversion Gravity and vertical gradient data Modified structural similarity index
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Characteristics of structural loess strength and preliminary framework for joint strength formula 被引量:18
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作者 Rong-jian LI Jun-ding LIU +2 位作者 Rui YAN Wen ZHENG Sheng-jun SHAO 《Water Science and Engineering》 EI CAS CSCD 2014年第3期319-330,共12页
The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress ( Kf line), and the strength failure envelope of structu... The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress ( Kf line), and the strength failure envelope of structurally intact loess and remolded loess were analyzed through three kinds of tests: the tensile strength test, the uniaxial compressive strength test, and the conventional triaxial shear strength test. Then, in order to describe the tensile strength and shear strength of structural loess comprehensively and reasonably, a joint strength formula for structural loess was established. This formula comprehensively considers tensile and shear properties. Studies have shown that the tensile strength exhibits a decreasing trend with increasing water content. When the water content is constant, the tensile strength of the structurally intact soil is greater than that ofremolded soil. In the studies, no loss of the originally cured cohesion in the structurally intact soil samples was observed, given that the soil samples did not experience loading disturbance during the uniaxial compressive strength test, meaning there is a high initial structural strength. The results of the conventional triaxial shear strength test show that the water content is correlated with the strength of the structural loess. When the water content is low, the structural properties are strong, and when the water content is high, the structural properties are weak, which means that the water content and the ambient pressure have significant effects on the stress-strain relationship of structural loess. The established joint strength formula of structural loess effectively avoids overestimating the role of soil tensile strength in the traditional theory of Mohr-Coulomb strength. 展开更多
关键词 structurally intact loess remolded loess tensile strength shear strength stress path failure envelope of principal stress Kf line) strength failure envelope joint strength formula
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Influence of Shim Layers on Progressive Failure of a Composite Componentin Composite-Aluminum Bolted Joint in Aerospace Structural Assembly 被引量:2
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作者 Cephas Yaw Attahu An Luling +1 位作者 Li Zhaoqing Gao Guoqiang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2018年第1期188-202,共15页
The influence of varying shim layers on the progressive damage/failure of a composite component in a bolted composite-aluminum aerospace structural assembly was investigated using a non-linear three-dimensional(3 D)st... The influence of varying shim layers on the progressive damage/failure of a composite component in a bolted composite-aluminum aerospace structural assembly was investigated using a non-linear three-dimensional(3 D)structural solid elements assembled model of a carbon fiber-reinforced polymer(CFRP)-aluminum single-lap joint with a titanium(Ti-6 Al-4 V)fastener and a washer generated with the commercial finite element(FE)software package,ABAQUS/Standard.A progressive failure algorithm written in Fortran code with a set of appropriate degradation rules was incorporated as a user subroutine in ABAQUS to simulate the non-linear damage behavior of the composite component in the composite-aluminum bolted aerospace structure.The assembled 3 DFE model simulated,as well as the specimen for the experimental testing consisted of a carbon-epoxy IMS-977-2 substrate,aluminum alloy 7075-T651 substrate,liquid shim(Hysol EA 9394),solid peelable fiberglass shim,a titanium fastener,and a washer.In distinction to previous investigations,the influence of shim layers(liquid shim and solid peelable fiberglass shim)inserted in-between the faying surfaces(CFRP and aluminum alloy substrates)were investigated by both numerical simulations and experimental work.The simulated model and test specimens conformed to the standard test configurations for both civil and military standards.The numerical simulations correlated well with the experimental results and it has been found that:(1)The shimming procedure as agreed upon by the aerospace industry for the resolution of assembly gaps in bolted joints for composite materials is the same for a composite-aluminum structure;liquid shim series(0.3,0.5 and 0.7 mm thicknesses)prolonged the service life of the composite component whereas a solid peelable fiberglass shim most definitely had a better influence on the 0.9 assembly gap compared with the liquid shim;(2)The shim layers considerably influenced the structural strength of the composite component by delaying its ultimate failure thereby increasing its service life;and(3)Increasing the shim layer′s thickness led to a significant corresponding effect on the stiffness but with minimal effect on the ultimate load. 展开更多
关键词 composite-aluminum progressive failure MODELING finite element MODELING single-lap BOLTED joint SHIMMING AEROSPACE structures
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Information Entropy Measures for Stand Structural Diversity:Joint Entropy 被引量:2
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作者 LeiXiangdong LuYuanchang 《Forestry Studies in China》 CAS 2004年第2期12-15,共4页
Structural diversity is the key attribute of a stand. A set of biodiversity measures in ecology was introduced in forest management for describing stand structure, of which Shannon information entropy (Shannon index) ... Structural diversity is the key attribute of a stand. A set of biodiversity measures in ecology was introduced in forest management for describing stand structure, of which Shannon information entropy (Shannon index) has been the most widely used measure of species diversity. It is generally thought that tree size diversity could serve as a good proxy for height diversity. However, tree size diversity and height diversity for stand structure is not completely consistent. Stand diameter cannot reflect height information completely. Either tree size diversity or height diversity is one-dimensional information entropy measure. This paper discussed the method of multiple-dimensional information entropy measure with the concept of joint entropy. It is suggested that joint entropy is a good measure for describing overall stand structural diversity. 展开更多
关键词 stand structural diversity Shannon index joint entropy conditional entropy
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Application of Modern Wood Product Glulam in Timber Frame With Tenon- Mortise Joints and Its Structural Behavior 被引量:2
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作者 Guofang Wu Yong Zhong +1 位作者 Yingchun Gong Haiqing Ren 《Journal of Renewable Materials》 SCIE 2019年第5期451-461,共11页
Tenon-mortise joint is widely used in traditional timber structures around the world.This paper summarizes the results of an experimental study of the structural behavior of tenon-mortise joints made with glulam and C... Tenon-mortise joint is widely used in traditional timber structures around the world.This paper summarizes the results of an experimental study of the structural behavior of tenon-mortise joints made with glulam and CNC technology instead of traditional material and manual work.30 full-scale tenonmortise joints were manufactured and tested under monotonic loading,and the effects of dimension,shape,processing error and adhesive were evaluated.It was found that the round rectangular shaped tenon-mortise joints were comparable with traditional joints in terms of structural performance,but were time and labor saving.The variability of the proposed tenon-mortise joints was lower,which would benefit the design value.Applying adhesive between tenon and mortise increased the average stiffness by 4.3 times and average moment capacity by 27.4%,respectively.The gaps between wood members had little effect on the capacity and stiffness in monotonic bending but may influence the energy dissipation ability in cyclic bending.This study showed the feasibility of combining the traditional joinery method with modern wood products and manufacturing technology,which may promote the application of tenon-mortise joints in modern timber structures. 展开更多
关键词 Tenon-mortise joint moment carrying capacity beam to column connection semi-rigid joint timber structure
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Nonlinear identification and characterization of structural joints based on vibration transmissibility 被引量:2
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作者 Liu Xin Sun Beibei +2 位作者 Li Lie Chen Jiandong Xue Fei 《Journal of Southeast University(English Edition)》 EI CAS 2018年第1期36-42,共7页
In order to investigate the nonlinear characteristics of structural joint,the experimental setup with a jointed mass system is established for dynamic characterization analysis and vibration prediction,and a correspon... In order to investigate the nonlinear characteristics of structural joint,the experimental setup with a jointed mass system is established for dynamic characterization analysis and vibration prediction,and a corresponding nonlinearity identification method is studied.First,the sine-sweep vibration test with different baseexcitation levels areapplied to the structural joint system to study the dominant modal of mass rigid motion.Then,based on t e harmonic balance method principle,t e measured vibration transmissibilities a e utilized for nonlinearity identification using different excitation levels.Experimental results show that nonlinear spring and damping force can be represented by a polynomial order approximation.The identified nonlinear stiffness and damping force can predict the system’s response,and they can reveal t e shifts of resonant frequency or damping due to discontinuity of contact mechanisms within a certain range. 展开更多
关键词 structural joint vibration transmissibility nonlinear identification harmonic balance method
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Nonlinear Modeling and Identification of Structural Joint by Response Control Vibration Test 被引量:1
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作者 LIU Xin WANG Lixiao +1 位作者 CHEN Qidong SUN Beibei 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2019年第6期964-976,共13页
Components of mechanical product are assembled by structural joints,such as bolting,riveting,welding,etc.Structural joints introduce nonlinearity to some engineering structures,and the nonlinearity need to be modeled ... Components of mechanical product are assembled by structural joints,such as bolting,riveting,welding,etc.Structural joints introduce nonlinearity to some engineering structures,and the nonlinearity need to be modeled precisely.To meet serious quality requirements,it is necessary to detect and identify nonlinearity of mechanical products for structural optimization.Modal test to acquire a dynamic response has been applied for decades,which provides reliable results for finite element(FE)model updating.Here response control vibration test for identification of nonlinearity is presented.A nonlinear system can be regarded as linearity for particular steady state response,and classical linear analysis tool is applicable to extract modal data for particular response.First,its applicability is illustrated by some numerical simulations.Subsequently,it is implemented on experimental setup with structural joints by shaking table.The stiffness and damping function dependent of relative displacement are fitted to describe its inherent nonlinearity.The spring and damping forces are identified by harmonic balance method(HBM)to predict output response.Based on the identified results,the procedure is recommended that it allows a reliable measurement of nonlinearity with a certain accuracy. 展开更多
关键词 nonlinear identification shaking table response control vibration test relative displacement structural joint constant response
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Effect of cold-working on corrosion induced damage in lug joints
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作者 Ramanath M.N Chikmath L. Murthy H. 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第6期175-182,共8页
Lug joints are preferred joineries for transferring heavy loads to parent components in aerospace vehicles.They experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement b... Lug joints are preferred joineries for transferring heavy loads to parent components in aerospace vehicles.They experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement between the pin and lug-hole.This causes damage of different sizes and shapes near the lug-hole.Stiffness degradation due to corrosion-induced damage is modelled as a through-pit at one of the identified critical locations through stress analysis.The effect of this pit on fatigue crack initiation life is estimated.Lug-hole is pre-stressed by cold-working and the benefits of inducing plastic wake on the intended performance of the lug joint during the damages due to corrosion are brought out and compared with non-cold-worked lug-hole.Numerical analysis is performed on this lug joint with pressfit.The results obtained highlight the benefits of cold-working and the methodology can be extended to damage growth and analyse the effect of surface treatments for better structural integrity of components of aerospace vehicles. 展开更多
关键词 Lug joint CORROSION Crack initiation COLD-WORKING structural integrity
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Structural Analysis of Platforms with the Effect of Joint Flexibility
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作者 Mu, Yang Zhang, Shengkun 《China Ocean Engineering》 SCIE EI 1993年第3期243-252,共10页
A modified space beam element is presented in this paper to consider the local joint flexibility of T, Y tubular joints subjected to axial forces and in-plane bending moments for analysis of platforms. Two numerical e... A modified space beam element is presented in this paper to consider the local joint flexibility of T, Y tubular joints subjected to axial forces and in-plane bending moments for analysis of platforms. Two numerical examples are shown to verify the efficiency and validity of the method presented here. 展开更多
关键词 Bending (deformation) joints (structural components) Loads (forces) Mathematical models Ocean engineering structural analysis WELDS
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Finite Element Analysis of Tubular KK Joint under Compressive Loading
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作者 Mohammad Tanzil Hasan Md. Jobayer Mia Md. Syful Isalm Bipul 《American Journal of Computational Mathematics》 2024年第3期291-304,共14页
KK tubular joints are used to build jacket-type offshore structures. These joints are mostly made up of structural steel. These joints can withstand yield, buckling, and lateral loads depending on the structure’s des... KK tubular joints are used to build jacket-type offshore structures. These joints are mostly made up of structural steel. These joints can withstand yield, buckling, and lateral loads depending on the structure’s design and environment. In this study, the Finite Element Model of the KK-type tubular joint has been created, and analysis has been performed under static loading using the Static Structural analysis system of ANSYS 19.2 commercial software and structural mechanics module of COMSOL Multiphysics. The KK tubular model is analyzed under compressive load conditions, and the resulting stress, strain, and deformation values are tabulated in both graphical and tabular form. This study includes a comparison of the outcomes from both commercial software. The results highlight that maximum stress, strain, and deformation values decrease as joint thickness increases. This study holds significant relevance in advancing the understanding of tubular KK joints and their response to compressive loading. The insights derived from the analysis have the potential to contribute to the development of more robust and reliable tubular KK joints in various engineering and structural applications. . 展开更多
关键词 KK joint BRACE Offshore structures CHORD Numerical Analysis Static Analysis
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Continuous Damage Monitoring of a Thin Composite Structural with Mismatched Stiffener in a Combined Joint Using Fiber Bragg Grating under Tension and Three-Point Loading
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作者 Agus Trilaksono Naoyuki Watanabe +3 位作者 Hikaru Hoshi Atsush Kondo Yutaka Iwahori Shin-Ichi Takeda 《Open Journal of Composite Materials》 2013年第3期63-87,共25页
A joint combining riveting and bonding is considered in terms of structural performance if the composite structure has a mismatched stiffener. The transfer loading is correlated with high performance aerospace joints ... A joint combining riveting and bonding is considered in terms of structural performance if the composite structure has a mismatched stiffener. The transfer loading is correlated with high performance aerospace joints to increase delamination resistance in the out-of-plane direction. However, combined joints (rivet/bonded) will create a bearing area that induces another potential damage source aside from secondary bending moment on the edge of the stiffener. Another problem is that the structure is difficult to be inspected by using conventional methods because of limited accessibility. The use of embedded fiber Bragg grating (FBG) technology in the structure as a strain sensor can potentially solve the problem in structures that have a stiffness mismatch. The FBG can be used to detect and characterize delamination before it reaches a critical stage. The model used to represent this problem is a thin composite stiffened skin under two load cases: tension and three-point bending. Finite element modeling using a traction versus separation theory is performed to determine the critical area on the specimen for placement of the FBG before manufacturing and testing. Experiments were presented to determine the distribution of load in a combined joint under both loading cases using ideal loads to create a secondary bending moment and bearing loads in the stiffness-mismatched structure. In this research, the FBG successfully detected and characterized the delamination caused in both loading cases. In addition, FBG can predict the delamination growth quantitatively. A spectrum graph of the FBG results can be used to replace the conventional mechanical graph in composite structural health monitoring in real applications. 展开更多
关键词 Carbon Fiber joints/Joining COHESIVE Elements Secondary BENDING MOMENT structural Health Monitoring
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Effects of Joint on Dynamics of Space Deployable Structure 被引量:5
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作者 GUO Hongwei ZHANG Jing +1 位作者 LIU Rongqiang DENG Zongquan 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第5期861-872,共12页
Joints are necessary components in large space deployable truss structures which have significant effects on dynamic behavior of these joint dominated structures.Previous researches usually analyzed effects of one or ... Joints are necessary components in large space deployable truss structures which have significant effects on dynamic behavior of these joint dominated structures.Previous researches usually analyzed effects of one or fewer joint characters on dynamics of jointed structures.Effects of joint stiffness,damping,location,number,clearance and contact stiffness on dynamics of jointed structures are systematically analyzed.Cantilever beam model containing linear joints is developed based on finite element method,influence of joint on natural frequencies and mode shapes of the jointed system are analyzed.Analytical results show that frequencies of jointed system decrease dramatically when peak mode shapes occur at joint locations,and there are cusp shapes present in mode shapes.System frequencies increase with joint damping increasing,there are different joint damping to achieve maximum system damping for different joint stiffness.Joint nonlinear force-displacement is described by describing function method,one-DOF model containing nonlinear joints is established to analyze joints freeplay and hysteresis nonlinearities.Analysis results show that nonlinear effects of freeplay and hysteresis make dynamic responses switch from one resonance frequency to another frequency when amplitude exceed demarcation values.Joint contact stiffness determine degree of system nonlinearity,while exciting force level,clearance and slipping force affect amplitude of dynamic response.Dynamic responses of joint dominated deployable truss structure under different sinusoidal exciting force levels are tested.The test results show obvious nonlinear behaviors contributed by joints,dynamic response shifts to lower frequency and higher amplitude as exciting force increasing.The test results are further compared with analytical results,and joint nonlinearity tested is coincident with hysteresis nonlinearity.Analysis method of joint effects on dynamic characteristics of jointed system is proposed,which can be used in optimal design of joint parameters to achieve optimum dynamic performance of jointed system. 展开更多
关键词 deployable structure joint DYNAMIC mode shape EXPERIMENT
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Practical Structural Design Approach of Multiconfiguration Planar Single‑Loop Metamorphic Mechanism with a Single Actuator 被引量:7
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作者 Qiang Yang Guangbo Hao +2 位作者 Shujun Li Hongguang Wang Haiyang Li 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2020年第5期19-33,共15页
As a type of multiconfiguration mechanism that can operate in an under-actuated state,metamorphic mechanisms were proposed more than two decades ago and attracted significant interest.Studies on structural synthesis o... As a type of multiconfiguration mechanism that can operate in an under-actuated state,metamorphic mechanisms were proposed more than two decades ago and attracted significant interest.Studies on structural synthesis of metamorphic mechanisms tend to focus more on metamorphic techniques and the structural synthesis of source mechanisms for metamorphic mechanisms.By designing different constraint architectures of metamorphic joints,multistructures can be obtained from the same source metamorphic mechanism.To determine the constraint architectures of metamorphic joints and their different assembly combinations,a kinematic status matrix and a corresponding constraint status matrix are constructed based on the metamorphic cyclogram of a source mechanism.According to the equivalent resistance gradient model and the constraint status matrix,an equivalent resistance matrix for the metamorphic joints is proposed.A structural synthesis matrix of the metamorphic mechanism is then obtained from the equivalent resistance matrix by deducing the constraint form vectors of the metamorphic joints.Furthermore,a kinematic diagram synthesis of the source metamorphic mechanism of a planar single-loop metamorphic mechanism is proposed,which is based on only the 14 one-or zero-degrees-of-freedom linkage groups.The entire structural design method of a metamorphic mechanism is based on the structural synthesis matrix and is presented as a systematic process.Finally,the proposed structural design approach is illustrated by two examples to verify its feasibility and practicality.This study provides an effective method for designing a practical multi-mobility and multiconfiguration planar single-loop metamorphic mechanism with a single actuator. 展开更多
关键词 Metamorphic mechanism structural design Form of metamorphic joints Multiconfiguration Equivalent resistance Single actuator
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Equivalent continuum modeling of beam-like truss structures with flexible joints 被引量:3
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作者 Fushou Liu Libin Wang +1 位作者 Dongping Jin Hao Wen 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2019年第5期1067-1078,共12页
The paper investigated the equivalent continuum modeling of beam-like repetitive truss structures considering the flexibility of joints,which models the contact between the truss member and joint by spring-damper with... The paper investigated the equivalent continuum modeling of beam-like repetitive truss structures considering the flexibility of joints,which models the contact between the truss member and joint by spring-damper with six directional stiffnesses and dampings.Firstly,a two-node hybrid joint-beam element was derived for modeling the truss member with flexible end joints,and a condensed model for the repeating element with flexible joints was obtained.Then,the energy equivalence method was adopted to equivalently model the truss structure with flexible joints and material damping as a spatial viscoelastic anisotropic beam model.Afterwards,the equations of motion for the equivalent beam model were derived and solved analytically in the frequency domain.In the numerical studies,the correctness of the presented method was verified by comparisons of the natural frequencies and frequency responses evaluated by the equivalent beam model with the results of the finite element method model. 展开更多
关键词 Large space TRUSS structure Flexible joint EQUIVALENT CONTINUUM modeling ANISOTROPIC BEAM model Frequency response
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Determining relative block structure rating for rock erodibility evaluation in the case of non-orthogonal joint sets 被引量:1
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作者 Lamine Boumaiza Ali Saeidi Marco Quirion 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2019年第1期72-87,共16页
The most commonly used method for assessing the hydraulic erodibility of rock is Annandale's method.This method is based on a correlation between the erosive force of flowing water and the capacity of rock resista... The most commonly used method for assessing the hydraulic erodibility of rock is Annandale's method.This method is based on a correlation between the erosive force of flowing water and the capacity of rock resistance. This capacity is evaluated using Kirsten's index, which was initially developed to evaluate the excavatability of earth materials. For rocky material, this index is determined according to certain geomechanical factors related to intact rock and rock mass, such as compressive strength of intact rock, rock block size, discontinuity shear strength and relative block structure. To quantify the relative block structure, Kirsten(1982) developed a mathematical expression that accounts for the shape and orientation of the blocks relative to the direction of flow. Kirsten's initial concept for assessing the relative block structure considers that the geological formation is mainly fractured by two joint sets forming an orthogonally fractured system. An adjusted concept is proposed to determine the relative block structure when the fractured system is non-orthogonal where the angle between the planes of the two joint sets is greater or less than 90°. An analysis of the proposed relative block structure rating shows that considering a non-orthogonally fractured system has a significant effect on Kirsten's index and, as a consequence, on the assessment of the hydraulic erodibility of rock. 展开更多
关键词 Fractured ROCK DIP angle DIP direction joint SPACING RELATIVE block structure Hydraulic ERODIBILITY of ROCK Annandale’s method Kirsten’s index
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Microstructure and mechanical properties of Cu/Al joints brazed using(Cu,Ni,Zr,Er)-modified Al−Si filler alloys 被引量:1
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作者 Hua-xin LI Ying-dian FENG +7 位作者 Wei-jian SHEN Chuan-yang LÜ Wen-jian ZHENG Ying-he MA Gang MA Zhong-ping JIN Yan-ming HE Jian-guo YANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第11期3623-3634,共12页
To design a promising Al−Si filler alloy with a relatively low melting-point,good strength and plasticity for the Cu/Al joint,the Cu,Ni,Zr and Er elements were innovatively added to modify the traditional Al−Si eutect... To design a promising Al−Si filler alloy with a relatively low melting-point,good strength and plasticity for the Cu/Al joint,the Cu,Ni,Zr and Er elements were innovatively added to modify the traditional Al−Si eutectic filler.The microstructure and mechanical properties of filler alloys and Cu/Al joints were investigated.The result indicated that the Al−Si−Ni−Cu filler alloys mainly consisted of Al(s,s),Al_(2)(Cu,Ni)and Si(s,s).The Al−10Si−2Ni−6Cu filler alloy exhibited relatively low solidus(521℃)and liquidus(577℃)temperature,good tensile strength(305.8 MPa)and fracture elongation(8.5%).The corresponding Cu/Al joint brazed using Al−10Si−2Ni−6Cu filler was mainly composed of Al_(8)(Mn,Fe)_(2)Si,Al_(2)(Cu,Ni)3,Al(Cu,Ni),Al_(2)(Cu,Ni)and Al(s,s),yielding a shear strength of(90.3±10.7)MPa.The joint strength was further improved to(94.6±2.5)MPa when the joint was brazed using the Al−10Si−2Ni−6Cu−0.2Er−0.2Zr filler alloy.Consequently,the(Cu,Ni,Zr,Er)-modified Al−Si filler alloy was suitable for obtaining high-quality Cu/Al brazed joints. 展开更多
关键词 Cu/Al joint BRAZING Al−Si filler alloy interface structure joint strength
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Analysis on seismic performance of a new type of joint in steel structures 被引量:1
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作者 Li Xiaodong Ma Guangtian Yan Yinji 《Journal of Southeast University(English Edition)》 EI CAS 2021年第3期290-298,共9页
To examine the seismic performance of a newly fabricated weakened joint at the beam end position,four groups of energy-consuming steel plates with different weakening depths and thicknesses were subjected to horizonta... To examine the seismic performance of a newly fabricated weakened joint at the beam end position,four groups of energy-consuming steel plates with different weakening depths and thicknesses were subjected to horizontal cyclic reciprocating loading tests on beam ends.The tests were designed to evaluate the beams'hysteresis curve,skeleton curve,bearing capacity degradation curve,stiffness degradation curve,and ductility and the nodes'energy dissipation capacity.The test results show that a newly fabricated joint will not undergo brittle damage when the beam-column joint is welded at a displacement of 105 mm.Thus,the hysteresis curve will show an inverse S shape,and an obvious slip phenomenon will occur,which is mainly due to splicing.The diameter of the bolt connecting the slab to the beam flange is slightly smaller than the aperture.Due to the existence of slippage,the skeleton curve has no evident yield point.The joint ductility coefficient is less than 3.0,and the initial rotational stiffness of the joint is also small.The buckling of the splicing panel causes a rapid decrease in the joint bearing capacity.The main approaches,appropriately reducing the weakening depth and increasing the thickness of the splicing plate,can delay the occurrence of buckling and improve the ductility of the joint. 展开更多
关键词 steel structure energy-dissipating members weakened joint seismic performance cyclic loading tests
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Effect of the Chord-Brace Angle on the Strength of Rectangular Hollow Sections K- and N-Joints in Galvanized Structures 被引量:1
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作者 Miguel A. Serrano Carlos Lopez-Colina +1 位作者 Gorka Iglesias Jorge Gonzailez 《Journal of Civil Engineering and Architecture》 2014年第10期1226-1232,共7页
An important consideration when using hot-dip galvanized tubular structures is the uncertainty of the joint behaviour due to the possible reduction in the global joint resistance produced by the vent holes required fo... An important consideration when using hot-dip galvanized tubular structures is the uncertainty of the joint behaviour due to the possible reduction in the global joint resistance produced by the vent holes required for the galvanizing process. This paper assesses the effect on the joint strength of the angle between the brace members and the chord in a K- or N-joints made with rectangular hollow sections. The study is focused on the case when those brace members include characteristic holes required for the hot-dip galvanizing process. To accomplish the objective of the proposed work, some tests on full-scale K- and N-joints, including angles of 35°, 45°, 55° and 90°, were carried out. The experimental work was complemented by a validated numerical simulation in order to give some design recommendations and to extend the research to other joint configurations. 展开更多
关键词 structural joints tubular structures galvanized structures experimental tests numerical simulation.
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Deep structural research of the South China Sea: Progresses and directions 被引量:4
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作者 Xu-wen Qin Bin Zhao +5 位作者 Fu-yuan Li Bao-jin Zhang Hou-jin Wang Ru-wei Zhang Jia-xiong He Xi Chen 《China Geology》 2019年第4期530-540,共11页
The South China Sea(SCS)is the hotspot of geological scientific research and nature resource exploration and development due to the potential for enormous hydrocarbon resource development and a complex formation and e... The South China Sea(SCS)is the hotspot of geological scientific research and nature resource exploration and development due to the potential for enormous hydrocarbon resource development and a complex formation and evolution process.The SCS has experienced complex geological processes including continental lithospheric breakup,seafloor spreading and oceanic crust subduction,which leads debates for decades.However,there are still no clear answers regarding to the following aspects:the crustal and Moho structure,the structure of the continent-ocean transition zone,the formation and evolution process and geodynamic mechanism,and deep processes and their coupling relationships with the petroliferous basins in the SCS.Under the guidance of the“Deep-Earth”science and technology innovation strategy of the Ministry of Natural Resources,deep structural and comprehensive geological research are carried out in the SCS.Geophysical investigations such as long array-large volume deep reflection seismic,gravity,magnetism and ocean bottom seismometer are carried out.The authors proposed that joint gravitymagnetic-seismic inversion should be used to obtain deep crustal information in the SCS and construct high resolution deep structural sections in different regions of the SCS.This paper systematically interpreted the formation and evolution of the SCS and explored the coupling relationship between deep structure and evolution of Mesozoic-Cenozoic basins in the SCS.It is of great significance for promoting the geosystem scientific research and resource exploration of the SCS. 展开更多
关键词 DEEP structure evolution DEEP seismic exploration joint inversion of gravity magnetic and seismicdata Oil gas and HYDRATE resource SURVEY ENGINEERING OCEANIC geological SURVEY ENGINEERING South China Sea China
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