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  • 工程力学
    Engineering Mechanics
    (月刊,1984年创刊)
    主管单位:中国科学技术协会
    主办单位:中国力学学会
    主  编:陆新征
    编辑出版:《工程力学》编辑部
    ISSN 1000-4750 CN 11-2595/O3
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SEISMIC FRAGILITY MODELS AND FORWARD-BACKWARD PROBABILISTIC RISK ANALYSIS IN SECOND-GENERATION PERFORMANCE-BASED EARTHQUAKE ENGINEERING
Lü Da-gang, LIU Yang, YU Xiao-hui
Engineering Mechanics    2019, 36 (9): 1-11,24.   DOI: 10.6052/j.issn.1000-4750.2018.07.ST08
Accepted: 22 January 2019

Abstract168)      PDF(pc) (631KB)(135)       Save
The seismic fragility in 2nd-generation performance-based earthquake engineering (PBEE) generally refers to the seismic capacities of both structural components and non-structural components. However, this concept is different from the definition and the content of seismic fragility in traditional seismic risk theory. To clarify the differences between the two fragility definitions, the definition and its probabilistic model for seismic fragility in traditional seismic risk theory are firstly introduced. And then, five seismic fragility models in 2nd-generation PBEE are identified:seismic demand fragility model, seismic capacity fragility model, seismic damage fragility model, seismic loss fragility model, and seismic decision fragility model. The differences and their relationships of the five seismic fragility models are pointed out. The analytical formulations for the probability models and their distribution parameters in a seismic demand fragility model and a seismic damage fragility model are derived. On the basis of the above theoretical deduce, the concepts of forward PBEE and backward PBEE are put forward according to the directions of uncertainty propagation. Through this new concept, the risk integration equation in 2nd-generation PBEE can be solved by different methods. By integrating the approximate formulation of seismic hazard and the analytical formulations of fragility probability models and their distribution parameters, the three probabilistic seismic risk formulations with the same formats for EDP, DM and DV levels are obtained via the methods of forward PBEE and backward PBEE. Through the study of this paper, the traditional seismic risk theory and the 2nd-generation PBEE are unified into a consistent theoretical framework.
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NUMERICAL SIMULATION ON DYNAMIC COMPRESSIVE BEHAVIOR OF ULTRA-HIGH TOUGHNESS CEMENTITIOUS-COMPOSITES
XU Shi-lang, CHEN Chao, LI Qing-hua, ZHAO Xin
Engineering Mechanics    2019, 36 (9): 50-59.   DOI: 10.6052/j.issn.1000-4750.2018.03.0147
Accepted: 12 July 2019

Abstract125)      PDF(pc) (2326KB)(142)       Save
Investigates the dynamic compressive behavior of PVA fiber reinforced ultra-high toughness cementitious-composites (PVA-UHTCC) using Split Hopkinson Pressure Bar (SHPB) test based on HJC constitutive model. Firstly, 21 parameters of HJC model are determined and the numerical simulation is verified. Then dynamic compressive stress-strain curves under 5 different strain rates are obtained for analyzing the strain-rate effects on Dynamic Increase Factor (DIF). The failure modes of specimens under different strain rates are also researched. The results show that with the increase of strain rate, DIF increases and the strain-hardening dominated behavior will transform into a strain-softening dominated behavior. Besides, PVA-UHTCC shows an obvious different strain-rate sensitivity in the different range of strain rates. Thusly, a functional expression between DIF and lgε is proposed. Compared with Steel Fiber Reinforced Cementitious Composites (SFRCC) and normal concrete, PVA-UHTCC has a lower strain-rate sensitivity. Finally, the crack propagation mechanism and failure modes are observed at LS-DYNA software to furtherly understand the dynamic compressive behavior of PVA-UHTCC.
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SOME NEW DEVELOPMENTS OF THE FIRE PERFORMANCE RESEARCH ON COMPOSITE STRUCTURES
SONG Tian-yi;HAN Lin-hai
Engineering Mechanics    2008, 25 (增刊Ⅱ): 230-253.  
Abstract1248)      PDF(pc) (1230KB)(579)       Save
The research on fire-endurance performance and fire-resistance design of composite structures is one of the hot topics in structural engineering. This paper briefly summarizes and reviews some of the recent progress on the fire performance of composite slabs, composite beams, composite columns, beam-column connections, frames and structural system. Finally, A number of issues need to be addressed on the fire performance of composite structures are identified and discussed.
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LITERATURE REVIEW OF RESEARCHES ON RIGID BODY MODEL OF ROCKING STRUCTURE
ZHAO Zi-xiang, SU Xiao-zu
Engineering Mechanics    2019, 36 (9): 12-24.   DOI: 10.6052/j.issn.1000-4750.2018.08.0454
Accepted: 29 April 2019

Abstract133)      PDF(pc) (701KB)(125)       Save
A rational theoretical model is essential for structure analysis. The most widely used model in theoretical research for rocking structure is rocking rigid body model, which is systematically reviewed in this paper. The research origin and research status of rocking rigid body model are introduced. The classical rocking rigid body model, and other typical rocking rigid body model, as well as related experimental research, finite element simulation and application in structure system, are discussed. The advantages and limitations of existing rocking rigid body models are discussed and key issues in future study of rocking rigid body model are highlighted, which provides reference for the establishment of a more complete and practical rigid body model for rocking structure and its application to the analysis of rocking structure.
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RESEARCH AND APPLICATIONS OF PREFABRICATED STEEL STRUCTURE BUILDING SYSTEMS
HAO Ji-ping, SUN Xiao-ling, XUE Qiang, FAN Chun-lei
Engineering Mechanics    2017, 34 (1): 1-13.   DOI: 10.6052/j.issn.1000-4750.2016.08.ST14
Abstract400)      PDF(pc) (3080KB)(430)       Save
The development of steel structures can resolve excess capacity of steel industry and promote building greenization, industrialization and informatization. Promoted by the national policy, the assembled steel structures in China have marched from v1.0 towards v2.0 quickly, during which three new types of building systems have been developed, including the improved system based on traditional steel structures, the modular construction system, and industrialized residential building system. Under the new situation, precast concrete components have solved the traditional problems of steel structures, new types of envelope system have been developed due to the application of different walls, and information technology speeded up the development of the construction industry. Fully assembled steel frames and box-type modular building systems are new types of low-rise multi-story construction system which use the design concept of "building elements". They are based on the combination of basic components including structural components and building functional units, which have the advantages of assembly, integrated envelope, industrialized production and so on. The new MCFTS (Multi-Core Concrete Filled Steel Tube System) high-rise steel structure system is suitable for residential and public buildings. The MCFTS consists of multi-core concrete filled steel tube frame-braced residential system and multi-core concrete filled steel shear-wall-concrete filled steel tube frame system for public buildings. The MCFTS takes the combination of multi-core concrete filled steel tube column and the double side plate beam-to-column connection as its core technology. It can be concluded that the system has excellent seismic performance and can be repaired.
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EXPERIMENTAL STUDY ON ASEISMIC BEHAVIOR OF LOCALLY USED HDC ASSEMBLED FRAME BEAM-COLUMN JOINTS
DENG Ming-ke, MA Fu-dong, YE Wang, YIN Peng-fei
Engineering Mechanics    2019, 36 (9): 68-78.   DOI: 10.6052/j.issn.1000-4750.2018.05.0263
Accepted: 29 April 2019

Abstract68)      PDF(pc) (1999KB)(70)       Save
In order to improve the deformation and energy dissipation capacity of fabricated beam-column joints and avoid the construction difficulties caused by crowded steel bars, high ductile fiber reinforced concrete (HDC) is used as the core material of beam-column joints. Considering the influence of axial compression ratio and stirrup ratio, 5 fabricated beam-column joints partly adopted HDC and 1 reinforced concrete (RC) beam-column joint were tested. The failure patterns, hysteretic characteristics, deformation capacity, stiffness degradation, energy dissipation capacity and shear deformation of the joint core area were analyzed. The results are as follow. First, failure position changed from node core area to beam end after adopted HDC in node core area. The design principle of a strong node is realized, and the deformation ability and energy dissipation capacity of frame nodes are effectively improved. Second, column ends should be strengthened because the failure position transferred to the end of column adopted HDC in the node area and beam end. Third, the amount of stirrups can be reduced when HDC is used in node core area.
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STABILITY AND VIBRATION BEHAVIOR OF FGM BEAMS UNDER HYGRO-THERMAL-MECHANICAL-ELASTIC LOADS
PU Yu, ZHOU Feng-xi
Engineering Mechanics    2019, 36 (9): 32-39.   DOI: 10.6052/j.issn.1000-4750.2018.08.0443
Accepted: 17 May 2019

Abstract75)      PDF(pc) (427KB)(75)       Save
The stability and vibration behavior of functionally graded material (FGM) beams resting on a Winkler-Pasternak elastic foundation under the action of initial axial mechanical load considering the hygro-thermal environment is investigated. Three hygro-thermal distributions through the thickness of the beams are assumed. The material properties are temperature-dependent and are distributed according to the Voigt mixture power law model. An n-th order generalized beam theory is proposed. The governing equations of buckling and free vibration are derived from the Hamilton's principle, in which the fundamental unknown functions are the axial displacement, bending and shear components of the transverse displacement. Applying the Navier method, the analytical solutions of the buckling and free vibration responses of FGM simply supported beams are obtained. The availability and accuracy of the n-th order generalized beam theory are tested and discussed through several numerical examples. The results show that it refines the beam theories and can be used as a benchmark to verify or modify other shear deformation beam theories. The effects of three types of hygro-thermal distribution, moisture and temperature rise, initial axial mechanical load, length-to-thickness ratio, elastic foundation stiffness and material graded index on the stability and vibration behavior of FGM beams are analyzed.
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INVERSE ANALYSIS OF INTERNAL DEFECTS IN STRUCTURES USING EXTENDED FINITE ELEMENT METHOD AND IMPROVED ARTIFICIAL BEE COLONY ALGORITHM
WANG Jia-ping, DU Cheng-bin, WANG Xiang, JIANG Shou-yan
Engineering Mechanics    2019, 36 (9): 25-31.   DOI: 10.6052/j.issn.1000-4750.2017.11.0874
Accepted: 26 July 2019

Abstract72)      PDF(pc) (506KB)(60)       Save
The information of defect in a structure is determined using the extended finite element method combined with a kind of improved artificial bee colony algorithm, based on real structural response. As searching optimal value may appear in an arbitrary direction in traditional artificial bee colony (ABC) algorithm, weighted average mutation and a cross operator are introduced to avoid the local optimum in the optimizing. The presented inverse method is also used to determine the location of a single-circular-like defect and an elliptical-like defeat and two irregular defects, and the robustness of the algorithm under the condition of measuring error is also studied. The numerical results indicate that the adapting artificial bee colony (AABC) algorithm proposed can present the real information of defects accurately. The convergence speed of AABC is faster than that of traditional ABC, and it is unlikely that the local optimum will appear in the optimizing. The presented method can locate the defects accurately and show a high robustness.
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SEISMIC MITIGATION EFFECT ANALYSIS ON FRICTION PENDULUM BEARINGAPPLIED IN THE UNDERGROUND SUBWAY STATION
DU Xiu-li, XU Zi-gang, XU Cheng-shun, JIANG Jia-wei
Engineering Mechanics    2019, 36 (9): 60-67,88.   DOI: 10.6052/j.issn.1000-4750.2018.04.0225
Accepted: 22 February 2019

Abstract61)      PDF(pc) (1067KB)(60)       Save
Based on the failure mode and damage mechanism of the Daikai subway station during Kobe earthquake, this paper proposes a new seismic mitigation structure. The friction pendulum bearing is installed at the top of the central columns, using the seismic isolation and mitigation design concept of surface structures. The 2D finite element models of soil-structure are analyzed, and then the seismic response of the original and proposed structure in different slide way radius and friction coefficient are compared by dynamic time history analysis method. The comparison results show that the new structure with friction pendulum bearing is softer than the original structure, resulting in a larger relative horizontal deformation. The deformation, shear forces and moments of the central columns are significantly reduced, when the slide way radius is large and the friction coefficient is small.
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INERTER SYSTEM AND ITS STATE-OF-THE-ART
ZHANG Rui-fu, CAO Yan-ru, PAN Chao
Engineering Mechanics    2019, 36 (10): 8-27.   DOI: 10.6052/j.issn.1000-4750.2018.09.0496
Accepted: 12 April 2019

Abstract124)      PDF(pc) (3418KB)(98)       Save
An inerter is a two-terminal acceleration-dependent mechanical element for structure control systems. The inerter system is an integrated system for the structural vibration control with inerters. A large number of studies and research projects on the inerter systems have been comprehensively reviewed in this paper. The state-of-the-art of inerter systems in the field of structural vibration control system were discussed from the following three aspects:realization of the inerter mechanism; performance of the inerter system and design of the structures with inerter system. Compared with traditional vibration control systems, the inerter system has its advantages including:the inertia of the structure can be adjusted and the tuning can be achieved flexibly; additional physical mass is negligible when the inertia of the structure changes obviously; the efficiency of energy dissipation is enhanced. This review paper is intended to provide theoretical evidence and practical guidance for the design, application and further development of inerter systems.
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COMPARISON ON THE SEISMIC DEISGN OF BASE-ISOLATED RC FRAMES USING TWO CHINESE CODES
YIN Chuan-yin, XIE Lin-lin, LI Ai-qun, ZENG De-min, CHEN Xi, GE Dong-dong, YANG Can-tian
Engineering Mechanics    2019, 36 (9): 197-204,212.   DOI: 10.6052/j.issn.1000-4750.2019.02.0044
Accepted: 23 May 2019

Abstract88)      PDF(pc) (651KB)(66)       Save
There will be two seismic design codes for the base-isolated structures in the near future in China, including Code for Seismic Design of Buildings and Code of Design for Seismic Isolated Buildings. It is notable that significant differences exist in terms of design methods and critical design indexes between these two codes. However, comparisons on the seismic design of base-isolated structures using these two codes are rarely reported. The seismically isolated reinforced concrete (RC) frame structure is herein selected as the study subject. Using three pairs of structure cases with different heights which were designed according to the two codes, the controlling factor for the seismic design of such structures using Code of Design for Seismic Isolated Buildings was identified. In addition, the seismic responses and economic investment of such structures designed according to the two codes were compared and analyzed. The results indicate that the abovementioned controlling factor is base shear ratio. For the superstructure, a smaller stiffness is selected if Code of Design for Seismic Isolated Buildings is adopted, and the corresponding seismic load reduces by approximately 15%~20% in comparison with that designed following Code for Seismic Design of Buildings. However, because the degree of stiffness reduction of superstructure is greater than that of seismic load reduction, a significant increase of maximum inter-story drift ratio (i.e., θmax) of superstructure is observed. Furthermore, the increment of θmax basically increases with the increase of total height of structure. As for the material consumption, the concrete consumption is reduced by 7.7%~12.1% while the reinforcement consumption is increases by 11.02%~26.29% if Code of Design for Seismic Isolated Buildings is adopted. With the increase of total height of structure, the reduction of concrete consumption increases, while the increment in reinforcement consumption decreases. The research outcome will assist in providing a useful reference for seismic design of base-isolated RC frame structures.
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RELIABILITY ANALYSIS OF THE VERTICAL PROGRESSIVE COLLAPSE OF BASE-ISOLATED FRAME-WALL STRUCTURES UNDER EARTHQUAKES
HUANG Xiao-ning, WANG Ning, DU Yong-feng
Engineering Mechanics    2019, 36 (9): 89-94,127.   DOI: 10.6052/j.issn.1000-4750.2018.07.0389
Accepted: 11 April 2019

Abstract39)      PDF(pc) (820KB)(40)       Save
Based on the introduction of a seismic damage model of isolators, a reliability analysis of base-isolated frame-wall structures was conducted using the global reliability method. First, the most probable isolators to fail under strong motions were identified by the seismic damage model of isolators. Considering the basic random variables of damaged structures, progressive collapse load factors were then obtained using the random vertical incremental dynamic analysis method. As a global performance parameter, the load factor was adopted in the performance-based seismic fragility analysis. Probability and reliability indices of progressive collapse were determined using the second-order fourth-moment method. On the basis of this method, the probability and reliability indices of vertical progressive collapse were obtained. By using this method, the performance of progressive collapse resistance and structural seismic damage can be acquired.
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COMPUTATIONAL INVESTIGATIONS FOR AERODYNAMIC CHARACTERISTIC ANALYSIS OF LOW REYNOLDS NUMBER DOUBLY-TANDEM WING CONFIGURATIONS
ZHANG Qing, YE Zheng-yin
Engineering Mechanics    2019, 36 (10): 244-256.   DOI: 10.6052/j.issn.1000-4750.2018.09.0514
Accepted: 25 June 2019

Abstract30)      PDF(pc) (17547KB)(23)       Save
As a configuration with high aerodynamic efficiency, a tandem wing is an innovative kind of aerodynamic configuration for flight vehicles with inflatable aerodynamic structures such as stratosphere airships or inflatable wings at low Reynolds number flow regimes. However, its aerodynamic characteristics are limited understanding because of complicated interferences of the two wings. Therefore, based on conducted wind tunnel experiments, computational simulations have been carried out. Then the effects of airfoil thickness, surface wavelet and hindwing deflection angle on general aerodynamic characteristics were compared and presented quantitatively. The computational results demonstrate that at the computational range of attack angle, tandem wing configuration could delay, or even suppress the trailing edge separation and then increase the aerodynamic efficiency significantly, thus it is concluded that the aerodynamic configuration is attractive and promising for UAVs or airships with flexible structures in the near future.
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ANALYTICAL SOLUTION FOR ONE-DIMENSIONAL RHEOLOGICAL CONSOLIDATION OF SOIL BASED ON CONTINUOUS DRAINAGE BOUNDARY
ZONG Meng-fan, WU Wen-bing, MEI Guo-xiong, LIANG Rong-zhu, TIAN Yi
Engineering Mechanics    2019, 36 (9): 79-88.   DOI: 10.6052/j.issn.1000-4750.2018.06.0349
Accepted: 09 September 2019

Abstract24)      PDF(pc) (445KB)(28)       Save
Based on a four-element rheological model, the one-dimensional rheological consolidation problem of soil under one-step loading was studied by introducing continuous drainage boundary conditions. The analytical solution under constant loading is obtained by the separation variable method and the Laplace transform technique, and the analytical solution under one-step loading is obtained by the integral method. Then, by degrading the drainage boundary and rheological model, the solution of one-dimensional rheological consolidation under the Terzaghi's boundary and the three-element rheological model is obtained, and the correctness of the present solution is verified by the comparison with existing solutions. Finally, the consolidation behavior of soil is analyzed for different interface parameters, rheological parameters or loading rate. The results show that:the difference between the consolidation solution based on continuous drainage boundary conditions and that based on Terzaghi's drainage is mainly in the early stage of consolidation, and the difference decreases with the increase of interface parameters α and β. The difference between rheological consolidation and linear elastic consolidation is mainly in the late stage of consolidation, and rheological consolidation requires a longer time for soil to be fully consolidated. In addition, the consolidation rate of soil increases with the increase of loading rate.
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ULTIMATE LOAD-CARRYING CAPACITY OF LONG-SPAN STEEL ARCH BRIDGES
CHENG Jin;JIANG Jian-jing;XIAO Ru-cheng;XIANG Hai-fan
Engineering Mechanics    2003, 20 (2): 7-10.  
Abstract750)      PDF(pc) (179KB)(505)       Save
With the increase of span of arch bridges, ultimate load-carrying capacity has received more attention in design and construction. In this paper, three methods for evaluation of the ultimate load-carrying capacity of longspan bridges are reviewed. A long-span half-through steel arch bridge of 550m central span under construction in China is studied. Results show that the overall safety of a long-span arch bridge depends primarily on the material nonlinearity of individual bridge element. The effects of different load distributions on the ultimate load-carrying capacity of the bridge are investigated.
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CONCEPT AND DEVELOPMENT OF NOVEL BLADE STRUCTURE OF LARGE HORIZONTAL-AXIS WIND TURBINE
YANG Yang, ZENG Pan, LEI Li-ping
Engineering Mechanics    2019, 36 (10): 1-7.   DOI: 10.6052/j.issn.1000-4750.2018.06.ST04
Accepted: 22 January 2019

Abstract31)      PDF(pc) (918KB)(41)       Save
During the development of large-scale horizontal axis wind turbines, the major problem is the contradiction among the structure reliability and the requirement of light weight and aerodynamics efficiency. The structural characteristics of a traditional cantilever blade has restricted the further development of large wind turbines. The novel form of a blade structure is the effective solution to the problem, such as bionic flexible blades, segmented blades and multi-element blades. This paper reviews the state of the art of novel blade structures in recent years, providing some references for large blade design.
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STUDY ON THE TIME HISTORY ENVELOPE FUNCTION OF GROUND MOTION BASED ON INPUT ENERGY
WANG De-cai, HUA Bei, CHONG Xun, JIANG Qing, YE Xian-guo
Engineering Mechanics    2019, 36 (9): 161-168.   DOI: 10.6052/j.issn.1000-4750.2018.08.0452
Accepted: 12 July 2019

Abstract34)      PDF(pc) (1897KB)(43)       Save
The conversion between power spectral density functions and response spectra is widely used in random vibration analysis and procedure of generating artificial ground motions, where the envelope function of ground motion has significant influence on the conversion results. In order to determine the parameters of the envelope function model reasonably, the conversion between nonstationary power spectra and input energy spectra is established based on the method of exact computation of input energy spectra from Fourier amplitude spectra. The influence of different parameters on power spectrum and input energy spectrum is analyzed. The average input energy spectrum of the natural ground motions matching the design spectrum is used for comparison. The values of different parameters of the envelope function model are obtained for the conversion between power spectra and design spectra of different site condition through comparing with the input energy spectra converted by design spectra. The rationality of the values of parameters is validated by the characteristics of input energy spectra of artificial records.
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DIRECT DISPLACEMENT-BASED BRACE PARAMETERS DESIGN AND ANALYSES OF STEEL FRAME WITH SELF-CENTERING BRACES
XU Long-he, YANG Xue-fei
Engineering Mechanics    2019, 36 (8): 141-148.   DOI: 10.6052/j.issn.1000-4750.2018.07.0406
Abstract52)      PDF(pc) (548KB)(48)       Save
The equivalent damping ratio expression of steel frame with pre-pressed spring self-centering energy dissipation (PS-SCED) brace is proposed and validated in this paper. Then the direct displacement-based seismic design method is employed to determine the brace parameters of a 6-story PS-SCED braced frame. The results show that the designed brace stiffness is conservative and the brace bearing capacity demand is too large when the equivalent damping ratio is not considered. However, considering the equivalent damping ratio design makes the stiffness and bearing capacity demand of PS-SCED brace smaller and enables the braced frame to meet the specified performance level. Under the same performance level, the brace stiffness ratio has little effect on the structural displacement responses. Therefore, the designed brace parameters according to the proposed stiffness ratio interval are capable of making the PS-SCED braced frame meet the requirement of deformation limit.
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THE INFLUENCE OF BIONIC AIRFOIL ON POWER EXTRACTION PERFORMANCE OF SEMI-ACTIVE FLAPPING WING
ZHU Jian-yang, ZHANG Jia-cheng, WANG Zhao
Engineering Mechanics    2019, 36 (10): 223-228,237.   DOI: 10.6052/j.issn.1000-4750.2018.10.0555
Accepted: 25 June 2019

Abstract25)      PDF(pc) (2455KB)(21)       Save
In order to analyze the effect of airfoil bionic shape onthe power extraction performance of semiactive flapping wing, a set of computational programiscompiled so as to effectively solve the fluid flow, active rotation and passive reciprocating flapping of airfoil by means ofan improved fluent fluid solver.Based on this developed program, four types of airfoils:dragonfly airfoil, seagull airfoil, NACA0012 and NACA0015 are studied, and the results show that the airfoils with bionic shape have better power extraction performance. Further analysis forthe flow field of flapping airfoils with different shapes shows that bionic airfoils can generate stronger vortices in the process of passive reciprocating flapping, and that the vortex shedding from the flapping airfoil surface in pitching motion is delayed, which results in the airfoil to have better energy extraction characteristics.
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CORRELATION BETWEEN STRUCTURAL FAILURE MODES AND CALCULATION OF SYSTEM RELIABILITY UNDER HAZARD LOADS
LI Gang;CHENG Geng-dong
Engineering Mechanics    2001, 18 (3): 1-9.  
Abstract688)      PDF(pc) (324KB)(340)       Save
The structural system reliability is an important factor of the structural overall performance. However, in civil engineering the concept of structural system reliability still stays at the stage of theoretical analysis, and there are hardly any practical applications due to the difficulties in calculation. With the high redundancy of civil engineering structures, the number of failure modes is numerous and the correlation between them is very complex. In the present paper, the property of hazard loads is studied by introducing the factor-load Roughness Index. Correlation between structural failure modes and the approximate approach of structural system reliability under hazard loads are studied. The following conclusions are reached: the structural failure modes under hazard loads are fully correlated and thus the structural system reliability under hazard loads can be determined by the weakest failure mode.
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RESEARCH ON SLIDING MODE DECENTRALIZED CONTROL BASED ON ADAPTIVE LEARNING RATE RBF NEURAL NETWORK FOR LARGE-SCALE ENGINEERING STRUCTURES
PAN Zhao-dong, LIU Liang-kun, TAN Ping, ZHOU Fu-lin
Engineering Mechanics    2019, 36 (9): 120-127.   DOI: 10.6052/j.issn.1000-4750.2018.07.0429
Accepted: 26 July 2019

Abstract42)      PDF(pc) (485KB)(58)       Save
This paper Proposes a decentralized adaptive learning rate RBF neural network sliding mode control (DALRBFSMC) algorithm for dealing with the influence and the uncertainty of the interaction forces between subsystems and the external loads. Lyapunov stability theory is employed to design the decentralized sliding mode control law which depends only on the displacement and the velocity response of relevant subsystems. Combined with RBF neural network theory and the classical gradient descent method, the adaptive learning rate of RBF network weights-adjustment is derived by using a Lyapunov function. And then the decentralized adaptive learning rate RBF neural network sliding mode control (DALRBFSMC) is designed, which can adjust the switching gain of the sliding mode control law in real time. An ASCE 9-story benchmark building is selected as a numerical example to evaluate the control performances of decentralized control and centralized control. Numerical simulation results indicate that the DALRBFSMC algorithm is suitable for different decentralized control strategy, and that overlapping decentralized control can perform up to a superior control performance when comparing with traditional centralized control, and also guarantee each of the actuators to be operating at maximum efficiency.
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SEISMIC BEHAVIOR OF WIDENED FLANGE CONNECTIONS WITH LYP160 STEEL COMPONENTS
WANG Meng, KE Xiao-gang
Engineering Mechanics    2019, 36 (8): 149-160.   DOI: 10.6052/j.issn.1000-4750.2018.07.0410
Abstract36)      PDF(pc) (2673KB)(35)       Save
To promote structural systems with replaceable components in the new urbanization process, connections with LYP160 steel cover-plate components in steel frame systems were improved by widening the beam flange section to increase the bearing capacity and fuse performance. A numerical model of full-bolted connections was established by using ABAQUS and was proven correct and applicable due to test results at home and abroad. Subsequently, cover-plate connection models with different degrees of widening and weakening of the flange were established. The load-carrying capacity, hysteretic behavior, fracture performance and energy dissipation capacity were compared, and the influence of the degree of widening on the seismic behavior of widened flange cover-plate connections with different degrees of weakening was discussed in depth. Finally, a design procedure was proposed to provide a basis for engineering application. The analysis results showed that widening the beam flange section can reduce the energy dissipation of the main frame and increase that of the cover-plate components. Widening the flange can also effectively transfer the position of the plastic hinge, and improve the effect and time of fuses. With the increase in the widening, the required design value of the bearing capacity was improved, which avoided excessive weakening and guaranteed the bearing capacity for normal use and the replaceable function of fuses. When the degree of widening reached a certain value, the influence of widening on the increase in the energy dissipation of cover-plate components was limited. Based on the calculation results, a relation curve of the limit value of bearing capacity coefficient and the widened flange coefficient was obtained. To ensure the full play of fuse, the design value of the bearing capacity coefficient should be less than the limit value, and the limit of the bearing capacity coefficient of the widened flange connection was 22% higher than that of the unwidened flange connection, indicating that the fuse effect will adequately exert with a smaller weakened degree of connection.
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THE INELASTICITY-SEPARATED SOLID ELEMENT MODEL AND COMPUTATIONAL EFFICIENCY ANALYSIS
LI Jia-long, LI Gang, LI Hong-nan
Engineering Mechanics    2019, 36 (9): 40-49,59.   DOI: 10.6052/j.issn.1000-4750.2018.07.0383
Accepted: 10 April 2019

Abstract39)      PDF(pc) (1258KB)(38)       Save
Due to the large number of elements required in the calculation of solid finite element models, large computational resource is consumed in the element state determination process and the factorization of the global tangent stiffness matrix with large dimensions, thus resulting in low efficiency. In this paper, linear tetrahedron and hexahedron isoparametric elements are established based on the inelasticity-separated finite element method. Six direct integration points are considered for hexahedron elements as the nonlinear strain interpolation points instead of eight gauss integration points, of which the computational accuracy is stable and the efficiency is improved. In addition, the main solving process of the governing equation is only the back substitution of the initial stiffness matrix and the matrix-vector multiplication by using the Woodbury formula and combined approximation approach. Therefore, the efficiency is significantly improved. Finally, the computational efficiency of the proposed method based on the time complexity theory indicates that, with the increase of the number of nodal degrees of freedom, the computational efficiency of the proposed method is significantly improved as compared with the traditional variable stiffness method. The numerical examples verify the correctness of the proposed solid element model and the high efficiency of the proposed algorithm.
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FLEXURAL BEHAVIOR AND CAPACITY ANALYSIS OF RC BEAMS WITH PERMANENT UHPC FORMWORK
LIANG Xing-wen, WANG Ping, XU Ming-xue, YU Jing, LI Lin
Engineering Mechanics    2019, 36 (9): 95-107.   DOI: 10.6052/j.issn.1000-4750.2018.07.0402
Accepted: 12 April 2019

Abstract41)      PDF(pc) (1514KB)(35)       Save
Four reinforced concrete (RC) beams with pre-fabricated permanent ultra-high performance concrete (UHPC) formworks and two RC beams were tested for flexural behavior. The reinforcement ratio and thickness of concrete cover were varied. The mechanical properties of pre-fabricated UHPC formwork RC beams and the interface bonding performance between UHPC formwork and post-cast-in-place concrete were mainly studied. The results show that when the load reached the peak value, no slip was observed on the interface between the prefabricated UHPC formwork and the post-cast-in-place concrete. The interface between the pre-fabricated UHPC formwork and the post-cast-in-situ concrete was slightly debonded after the peak load. Cracking load of prefabricated UHPC formwork RC beams increased by approximately 50%, and the yield load and ultimate load increased by about 10%, compared to that of standard RC beams. A flexural capacity calculation model of the pre-fabricated UHPC formwork RC beams was established based on the section balance condition, the assumption of plane section and the constitutive relation amongst UHPC, plain concrete and the reinforcement. The calculation results of flexural capacity agreed well with the experimental results.
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Steel rust layer form of sustained load segments under combined action of chloride ion and stray current
YU Shuo, JIN Hao, ZHOU Shun-hua, BI Xiang-li
Engineering Mechanics    2019, 36 (7): 174-183.   DOI: 10.6052/j.issn.1000-4750.2018.06.0354
Abstract39)      PDF(pc) (1840KB)(33)       Save
Under the influence of stray current as well as chloride ion and external load, the shield tunnel steel easily appear corrosion during its service period. Therefore, a three-dimensional numerical model is established in an electrical as well as chemical and mechanical coupling field. The change rule of segment steel corrosion rate at arch and the steel rust layer distribution form are analyzed. The results show that:1) the steel corrosion rate near the segment outside is larger than that near the inside, the intersection angle between the direction of maximum steel corrosion rate and the circle center line is 0°~52°; 2) the segment steel corrosion rate is related to volumetric strain under loading, and the segment steel corrosion rate in the middle is larger than that in the two ends; 3) when the steel occur depassivation, the steel corrosion rate increases linearly with the potential difference of cathode to anode, and it increases logarithmically with the chloride ion content; 4) under the joint action of three factors, the segment steel rust layer form appear eccentric circle, and the radius size and circular center are related to the non-uniform corrosion coefficient as well as the maximum corrosion current density.
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NUMERICAL SIMULATION AND ANALYSIS OF ‘TIME-VARYING CANOPY EFFECT’ OF MOISTURE TRANSPORT IN SUBGRADE SOIL
SONG Er-xiang, TONG Rui, LUO Shuang, LI Peng
Engineering Mechanics    2019, 36 (8): 30-39.   DOI: 10.6052/j.issn.1000-4750.2018.09.0505
Abstract53)      PDF(pc) (690KB)(55)       Save
The top cover condition of railway subgrade may change from evaporation boundary to sealed boundary after frozen in winter time, which will influence the transportation of moisture up from the bottom and its accumulation beneath the frozen surface. The concept of ‘time-varying canopy effect’ is introduced and a mathematical model is established for its analysis based on the non-isothermal coupled water and heat migration model as well as the rigid ice model. Water migration in one-dimension soil column is simulated considering constant canopy effect and ‘time-varying canopy effect’ respectively. Simulation results show that the frost heave under time-varying canopy conditions is smaller than that under constant canopy conditions, but it may still be large enough to disturb the normal performance of the railway. The influences of soil type, temperature difference and initial water content on the ‘time-varying canopy effect’ are also discussed.
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STABILITY ANALYSIS AND STRENGTHENING OF RECTANGULAR LONGITUDINAL EXTERIOR WALL IN STAIRCASES
WEI Bo-chen, ZHANG Jing-shu, YU Xiao-xu, LIU Tao
Engineering Mechanics    2019, 36 (8): 133-140.   DOI: 10.6052/j.issn.1000-4750.2018.07.0403
Abstract44)      PDF(pc) (511KB)(32)       Save
High-rise buildings are often associated with stability problems of longitudinal exterior walls in staircases. The longitudinal exterior walls, of no support, are generally connected to other parts of the building by coupling beams. In traditional structure design, the stability of the walls is often overestimated when the walls subject to transverse bending. This study investigated the stability issue of out-plane bending of longitudinal stair walls under self-weight. Firstly, a theoretical method was proposed to calculate the critical loading based on the energy principles. The theoretical results were in good agreement with the results of finite element simulation. Subsequently, a high-rise shear wall structure was taken into consideration as a case study. The results show that the instability of the rectangular longitudinal exterior wall in staircase might occur. Finally, four measures were suggested to maintain the wall stability:1) adding flanges or air shafts; 2) anchoring the distributed reinforcements of stair slabs into the rectangular wall; 3) replacing the rectangular wall with the infill wall, and 4) calculating the earthquake action without taking into account the rectangular wall. Based on the analysis results of the four measures, it has been concluded that abolishing the rectangular wall, arranging the beam at the story height, and setting the lightweight infill wall on the beam can avoid the stability issue of the rectangular wall in a staircase. This measure is easy to construct and is recommended. However, in seismic zones, improving the collapse-resistant capacity of lightweight infill walls in staircases is necessary to keep the emergency exit unimpeded.
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A SIMPLIFIED MODEL FOR SEISMIC RESILIENCE IMPROVEMENT OF REGIONAL RC FRAME STRUCTURES USING SEISMIC ISOLATION
LU Jia-ming, XIE Lin-lin, LI Ai-qun, ZENG De-min, YANG Can-tian, LIU Qian-min
Engineering Mechanics    2019, 36 (8): 226-234,247.   DOI: 10.6052/j.issn.1000-4750.2019.02.0057
Abstract51)      PDF(pc) (1339KB)(50)       Save
Seismic resilience of structures has become a critical issue in earthquake engineering worldwide, recently. RC frame structure, as a typical structure, is selected as the research object here. Considering the computational efficiency and accuracy, a simplified model for it was suggested and investigated with emphasis put on the critical requirements of seismic resilience of RC frames with seismic isolation, including the capacities of predicting critical design indices, seismic responses and resilient performance. Employing a basic case, the prediction accuracy of the widely-used hybrid simplified model based on shear beam (referred to as "HSS model" hereafter) was evaluated firstly. The results indicate that such model cannot predict the critical design index (i.e. base shear ratio) well. Furthermore, it is not capable of predicting the maximum absolute floor acceleration, which is the critical seismic response affecting seismic resilience. In view of these, a hybrid simplified model based on Timoshenko beam (referred to as "HST model" hereafter) was recommended and validated to be capable of predicting the abovementioned critical design index and seismic response. Based on this model, the seismic resilience improvement using seismic isolation was analyzed for an existing RC frame structure. Subsequently, the corresponding results were used to guide the detailed design of seismic isolation scheme. The results indicate that HST model can well predict the critical design index and seismic response. Furthermore, the relative errors of resilient performances predicted by the refined model and HST model are less than 4.5%. In contrast, relative errors are as large as 177% and 31.5% for the repair cost and repair time predicted by HSS model, respectively. The research outcome proves that the recommended model (i.e. HST model) can be used for analyzing the seismic resilience improvement based on seismic isolation.
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STUDY ON THE GEORISK MIS OF HIGH SLOPES AT MOUNTAINOUS REGION CITIES
WEN Hai-jia;LI Xin;ZHANG Yong-xing
Engineering Mechanics    2010, 27 (增刊I): 168-171.  
Abstract1342)      PDF(pc) (309KB)(450)       Save
The occurrence of Geotechnical catastrophe caused by high slope has haltered the economic development of mountain cities. A risk management information system based on the GIS is established by integrating the high slope risk evaluation model of mountainous cities with the graphic processing and the spatial analysis function of the GIS. The system is composed of database module, editing module, analyses module, query and display module as well as webgis module. On the basis of collection, storing, searching, and management for the relevant information, the system can perform the regional assessment and vulnerability assessment of geotechnical high slope risk.
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MECHANICAL PROPERTIES ANALYSIS AND EXPERIMENTAL RESEARCH ON MAGNIFIED VISCOUS DAMPING WALL
LIU Wen-guang, ZHANG Xin, GUO Yan, ZHANG Qiang
Engineering Mechanics    2019, 36 (8): 40-48.   DOI: 10.6052/j.issn.1000-4750.2018.10.0534
Abstract52)      PDF(pc) (879KB)(70)       Save
An amplified multi-lever parallel viscous damping wall was proposed. Given its structure and force characteristics, vertical pulling effect, the damping force and energy dissipation theoretical formulas of both common and magnified viscous damping walls were analyzed, as well as its deformation and energy dissipation. An experimental model of both common and magnified viscous damping walls with triple displacements was designed to carry out a reciprocating loading test under the action of a sine wave. The hysteresis curve of viscous damping wall was verified by the comparison between a theoretical curve and the experimental curve under different experimental conditions. Furthermore, the hysteretic curve of the amplified viscous damping wall was rounder than that of a normal damping wall, and the energy dissipation was more significant under the same displacements. Therefore, the three-storey concrete frame structure was used as the calculation model for seismic analysis, which confirms the influence of vertical pulling was effective to the structure of a magnified viscous damping wall.
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DISCUSSION AND DEFINITION ON YIELD POINTS OF MATERIALS, MEMBERS AND STRUCTURES
FENG Peng, QIANG Han-lin, YE Lie-ping
Engineering Mechanics    2017, 34 (3): 36-46.   DOI: 10.6052/j.issn.1000-4750.2016.03.0192
Abstract469)      PDF(pc) (944KB)(506)       Save
The yield point is a very critical characteristic of structural performance in design and research of engineering structures, which is the basis of evaluating properties such as ductility, yield-ultimate ratio and so on. However, there is no unified definition and expression for yield point of structures. With the development of new mechanical behavior of emerging structural materials, the existing graphic method, the equivalent energy method, and the residual plastic deformation method are not suitable for them. In this paper, a unified expression of yield point for the typical materials including steel, concrete and fiber reinforced polymer is given based on the original definition of metal yielding under uniaxial tension. Then, for structural members and structures, the definition of the yield point based on the application conditions and the physical reality is proposed, which provides the basis for design of emerging material structures. As examples, this definition is applicable for reinforced concrete beams and short columns. Furthermore, a simplified method named Farthest Point Method is given, which has a specific physical meaning and a wide applicability. This method is more suitable for the computer programming. Based on existing experimental results of members and structures, the rationality of the farthest point method is verified by comparing the yield points defined by farthest point method and the presented definition. Thus, an explicit and unified definition for yield points of materials, members and structures is given in terms of the fundamentals and determination approach.
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AN EXPERIMENTAL INVESTIGATION ON THE LOW SPEED VERTICAL WATER-ENTRY OF HOLLOW CYLINDERS
HOU Yu, HUANG Zhen-gui, CHEN Zhi-hua, LUO Yu-chuan
Engineering Mechanics    2019, 36 (9): 237-246.   DOI: 10.6052/j.issn.1000-4750.2018.08.0440
Accepted: 12 April 2019

Abstract54)      PDF(pc) (2906KB)(31)       Save
To reveal cavity evolution rules of the low speed vertical water-entry of hollow cylinders, an experiment was conducted incorporating high-speed video cameras and the visualization technique. According to the images of the flow patterns and motion parameters, the effects of hollow structures on cavity pinch-off, bubble evolution and velocity changes were addressed during the water-entry process. The results show that the deep-closed cavity at low water-entry speed collapses to an arc line between through-hole jets and cavitating flow instead of a point under the free surface. Therefore, the bubble shedding in steps, annular cavity on the jet and cloud cavity are observed at the stabilization stage of the cavity. The increase of water-entry velocity makes the cavity change from deep-closure to surface-closure with the cavity volume changed and different shedding patterns of the tail bubbles. The surface tension around the droplet presents minor effects on the overall motion of jets with a small bubble, which is approximately regarded as toss motion under gravity. The inflow in the hole contributes to the stability of the movement and the resistance curve has two types of changes and more inflection points with higher water-entry velocities.
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A COUPLED MOISTURE-HEAT MODEL FOR UNSATURATED SOIL BASED ON LATTICE BOLTZMANN METHOD
LI Teng-feng, WANG Zhi-liang, SHEN Lin-fang, XU Ze-min
Engineering Mechanics    2019, 36 (9): 154-160,196.   DOI: 10.6052/j.issn.1000-4750.2018.08.0449
Accepted: 25 March 2019

Abstract22)      PDF(pc) (576KB)(22)       Save
By considering the moisture-heat coupling mechanism of unsaturated soil under heat source, the double distribution functions are employed to describe the evolution of temperature field and moisture field respectively, and the coupled moisture-heat model is established based on the lattice Boltzmann method. Meanwhile, the corresponding program is compiled to verify the proposed model, using an example of moisture-heat coupling problem in the semi-infinite space. Finally, the evolution of temperature field and moisture field in unsaturated soil are discussed considering the effects of moisture-heat coupling mode, heat source temperature, and soil porosity. The results show that the traditional one-way coupling mode could not characterize the influence of moisture migration on the thermal conductivity of soil, which leads to deviation of temperature field. The proposed two-way coupling mode is more reasonable. The evolution of temperature field and moisture field are greatly influenced by the heat source temperature, and the volume moisture content also changes rapidly at locations where the temperature of unsaturated soil rises fast. Under the same heat source, when the initial volume moisture content is constant, the temperature increases faster for the soil with lower porosity, but the overall difference is not significant, which makes the distribution of volume moisture content very close.
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EXPERIMENTAL STUDY ON BOND-SLIP BEHAVIOR AND BEARING CAPACITY OF CORRUGATED STEEL PLATE CONCRETE COMPOSITE MEMBER WITH STUD
WANG Wei, ZHAO Chun-lei, SU San-qing, REN Tan, LIU Ge-wei, DONG Chen-yang
Engineering Mechanics    2019, 36 (9): 108-119.   DOI: 10.6052/j.issn.1000-4750.2018.07.0411
Accepted: 31 May 2019

Abstract42)      PDF(pc) (797KB)(54)       Save
Eleven corrugated-steel-plate concrete composite members with studs and one comparative corrugated-steel-plate concrete member without studs on the surface of corrugated steel plate were statically tested to study the failure pattern, crack mode, load-slip characteristics, corrugated steel plate strain distribution and bearing capacity of corrugated-steel-plate concrete specimens with studs. The test results exhibit that concrete split failure is the main failure pattern of specimens with studs. The load-slip curves of specimens consists of the rising stage, the descending stage and the residual stage. Due to the action of concrete and studs, the free end of the corrugated steel plate has a tension stress area and a zero-value crossing phenomenon is generated. The shear bearing capacity of corrugated-steel-plate concrete composite specimens increases linearly with the increasing of diameter and quantity of the studs, but it is little affected by the stud length and thickness of corrugated steel plate. In addition, increasing the spacing of the studs within the range of 200 mm can improve the shear bearing capacity. Based on the analysis on experimental results and force spread principles of the specimens, both the constitutive model for the interface bond-slip of corrugated-steel-plate concrete considering the effect of studs and the formula for calculating the bearing capacity are presented. The results from the proposed model is in a good agreement with test results. The results of the bearing capacity formula are not only generally consistent with the test results, but also on the safe side.
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STUDY ON SHEAR STRENGTH ANALYSIS FOR A NEW TYPE LIGHT STEEL-FRAMED COMPOSITE WALL FILLED WITH FOAM CONCRETE
TIAN Wen-ling, WEN Xiao-dong, PENG Jia-bin, XU Li-li, LI Zi-xiang
Engineering Mechanics    2019, 36 (9): 143-153.   DOI: 10.6052/j.issn.1000-4750.2018.08.0448
Accepted: 15 April 2019

Abstract62)      PDF(pc) (1957KB)(63)       Save
To obtain a practical calculation method for the shear strength of light steel-framed composite walls covered with skin plates and a new type light steel-framed composite wall filled with foam concrete, four walls of identical dimensions, DD-1, DD-2, DD-1(D-300), DD-2(D-400), were subjected to monotonic loading and another two walls of identical dimensions, DZ-1(D-300), DZ-2(D-400), were subjected to reversed cyclic loading. On the experimental basis, a shear strength calculation method is established based on the bolt group failure model of light steel-framed composite walls covered with skin plates. The lightweight steel-lightweight concrete models and the strut-and-tie model are adopted to simplify the new type light steel-framed composite walls filled with foam concrete so as to derive a practical shear strength formula of the wall. The shear strength formula is revised according to the experimental results. The revised calculation results have good agreement with the experimental results. The lightweight steel-lightweight concrete model exhibits a higher agreement. The results can be used as a reference for structural design and construction.
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THE SHEAR STRENGTH AND MODE II FRACTURE TOUGHNESS OF LAYERED CONCRETE
QIN Xi, XU Qian-jun
Engineering Mechanics    2019, 36 (9): 188-196.   DOI: 10.6052/j.issn.1000-4750.2018.08.0468
Accepted: 16 April 2019

Abstract51)      PDF(pc) (957KB)(52)       Save
The bond characteristics of layered concrete was studied by direct shear tests and double-edge notched single-edge compressing tests (DNSCT) to obtain the parameters of shear strength and mode Ⅱ fracture toughness. The influence of the pouring interval of two layers on the bond characteristics was researched. A linear relation between the cohesive and the mode Ⅱ fracture toughness was found, while there is no remarkable relation between the friction coefficient and the mode Ⅱ fracture toughness. According to the definition of the mode Ⅱ fracture, Mohr-Coulomb criterion was used to judge the mode Ⅱ fracture. A linear relation between the cohesive and the mode Ⅱ fracture toughness was derived theoretically. The mode Ⅱ fracture toughness could be estimated based on the cohesive strength so that the mode Ⅱ fracture tests which are complex and uncontrollable could be avoided. This research can provide referable parameters for the fracture mechanics study of layered concrete.
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CAE ANALYSIS TECHNIQUES OF AUTOMOTIVE HANDLING AND STABILITY CHARACTERISTICS AND APPLICATIONS
CHANG Fang;LU Zhen-hua;GUO Kong-hui
Engineering Mechanics    2009, 26 (12): 196-203.  
Abstract1484)      PDF(pc) (4276KB)(913)       Save
Based on the automotive multi-body models of a dynamic system as well as according to corresponding experiment standards, the virtual experiments of automotive handling and stability were carried out under conditions of step steering angle input, stable-state cornering and impulse steering angle input, respectively. The simulation methods of automotive handling and stability characteristics by using virtual experiments techniques were implemented and summarized in details. Some key factors affecting the computation accuracy were studied and checked by comparing both results of the experiments and simulations. The optimization of automotive handling and stability characteristics was tried using method of Design of Experiments, and influences of rubber bushing stiffness to the car steering performance under step steering angle input were investigated.
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SIMULATION AND OPTIMUM DESIGN OF TRANSIENT MIXED FREE-SURFACE-PRESSURE FLOW FOR THE HYDROPOWER STATION
CHU Bao-xin;FAN Hong-gang;CHEN Nai-xiang
Engineering Mechanics    2003, 20 (4): 166-170.  
Abstract671)      PDF(pc) (323KB)(290)       Save
In tailrace tunnels of some hydropower stations, a transient Mixed Free-Surface-Pressure Flow (MFSPF) may occur, so a global computer model that can detect and simulate the mixed flow is needed. In this paper, a new MFSPF computation method (Characteristic Implicit Method) with good stability based on implicit finite difference scheme has been offered. Transient simulation programs have been developed based on the new method and other computation models for large-scale hydropower stations with MFSPF. By use of these programs, transient simulations of four large-scale Hydropower Stations such as the Three Gorges and the Xiluodu are studied. And the pressures in tailrace tunnel with MFSPF and other flow are analyzed and compared. Suggestions are made for the optimum design of tailrace tunnels with MFSPF.
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LONG-TERM BEHAVIOR OF COMPOSITE BEAM INCORPORATING SHEAR LAG EFFECT
MIAO Lin, CHEN De-wei
Engineering Mechanics    DOI: 10.6052/j.issn.1000-4750.2010.12.0941
COMPARISON STUDY OF CONSTITUTIVE MODEL OF CONCRETE IN ABAQUS FOR STATIC ANALYSIS OF STRUCTURES
NIE Jian-guo,WANG Yu-hang
Engineering Mechanics    2013, 30 (4): 59-67.   DOI: 10.6052/j.issn.1000-4750.2011.07.0420
Abstract2574)      PDF(pc) (964KB)(2109)       Save

The smeared crack and plasticity damage models in general finite element program ABAQUS were detailed introduced, including the uniaxial stress-strain relationship, crack model, yield criterion, flow rules and hysteretic rules. Then comparison and analysis were made on the key factors of concrete constitutive models that have effect on the static mechanical behavior of structural members. The mechanical behavior of reinforced concrete members and steel-concrete composite members under monotonic and cyclic loadings were simulated using various concrete constitutive models, thusly the suitable model could be chosen when analyzing structural members according to the comparison results.

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