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2015 Vol. 34, No. 13
Published: 2015-07-15
 
1 Ballistic Limit Velocity of Tungsten Alloy Spherical Fragment Penetrating Ceramic/DFRP Composite Target Plates
Mao Liang1，Wang Hua1，Jiang Chun-lan 2，Li,Ming2
An experimental study on the ballistic limit velocities (v50) of tungsten alloy spherical fragment penetrating Ceramic/DFRP composite target plates were carried out. Firstly, the tungsten alloy spherical fragment impacted different thickness ratio of ceramic/DFRP composite target plates were studied by using ballistic gun equipment. According to the ballistic experimental results, the relationship between ballistic limit velocity (v50) and area density (AD) of composite target was obtained. Secondly, according to the dimensional analysis method and the similarity theory, the simulation law of tungsten alloy spherical fragments penetrating ceramic/DFRP composite target plates was researched. Based on the above results, the empirical formula of ballistic limit velocity v50 was built. The predictive value using the empirical formula was consistent with the experimental results. The research results were valuable for designing fragment warhead and light armor protective structure.
2015 Vol. 34 (13): 1-5 [Abstract] ( 301 ) HTML (1 KB)  PDF (1264 KB)  ( 575 )
6  Research on Seismic Response of Bridges Crossing Active Fault and Best Crossing Angle
Hui Yingxin1,2 Wang Kehai1,2 Wu Gang1,2 LI Chong1,2
This paper presents a study on seismic response feature and the best crossing angle for the bridges crossing active fault. One bridge crossing strike-slip active fault was taken as an example. The seismic ground motions at the site of the bridge are generated following a hybrid simulation methodology. Multi-support excitations displacement input models and nonlinear time history analysis was used to calculate seismic response of structures. The influences of the crossing angle θ between bridge and fault on seismic response is also analyzed and the influence law and variation curve were acquired. The results showed that design pier torque values of bridge crossing fault was greater, and pier transverse bending moment increased with the decreased of the fault distance. The displacement response is with the main characteristics as large displacement and plane torsional deformation of main girder, residual displacement of bearings and piers, which pose significant unseating risk. When the bridge vertically across the fault（θ=90°）, the optimal rationality and economy for piers internal force is presented, the bridge axial displacement component caused by fault dislocation is minimal, accordingly, the risk of unseating is relatively low. The results provide in this research can be used as a reference to the seismic design and bridge location.
2015 Vol. 34 (13): 6-11 [Abstract] ( 184 ) HTML (1 KB)  PDF (2340 KB)  ( 466 )
12 Experimental and modeling investigation into damage of pressure vessels’ rear wall produced by hypervelocity impact on pressure vessels
GAI Fang-fang 1 CAI Yuan 2 HAO Jun-cai 1 QIAO Mu 1

Ground simulation impact experiment and theoretical analysis method is used for investigate damage characteristic of pressure vessel rear wall by spherical projectiles hypervelocity impact on gas-filled pressure vessels at normal angles. First, experiments of spherical projectiles hypervelocity impact on gas-filled pressure vessels are performed by two stage light gas gun loading technique, the damage characteristic of pressure vessel rear wall is obtained. based on linear-elastic fracture mechanics theory and elastic mechanics theory, simplified model prediction model for damage of pressure vessels is build on different fragmentized patterns of projectiles. In the model the rear wall is assumed to be fixed plate, the debris cloud and gas shock wave is assumed to be uniformly load. To verify the effectiveness of the model through the comparison with experimental results. The critical condition of rear wall perforation and crack, and damage size under the action of debris cloud and gas shock wave is obtained. The critical condition of catastrophic rupture of rear wall in the conditions of considering the curvature effect is obtained.
2015 Vol. 34 (13): 12-17 [Abstract] ( 218 ) HTML (1 KB)  PDF (1366 KB)  ( 205 )
18 Wave Propagation Analysis of Functionally Graded Material Structures Using Time-Domain Spectral Element
XU Chao WANG Teng
A new arbitrary quadrangular Gauss-Lobatto-Legendre time-domain spectral element was established, considering spatially continuous variation of material property of functionally graded material structures in the macroscopic sense. The variation of material property was modeled by the uniformed model, layer-wise model and continuous material model, respectively. Wave dynamic response in functionally graded structure under a central impact load was studied. The proposed element was verified through comparisons to the analytical solution of reference literature. Characteristics of high-frequency guided wave propagation in planar functionally graded material structures were investigated. Numerical Results demonstrate that uniformed model fails to describe the wave field behavior in the graded material structure. There are obvious differences about Amplitude of wave response, phase and phase velocity calculated by layer-wise model and continuous model. Continuous model can simulate the spatially variation of material property better. Symmetry longitudinal wave and asymmetry transverse wave doesn’t disperse obviously, while symmetry transverse wave disperse obviously.   
2015 Vol. 34 (13): 18-23 [Abstract] ( 246 ) HTML (1 KB)  PDF (1549 KB)  ( 263 )
24 Mining Dump Truck Ride Optimization Based on Identification Road
ZHU Yi-fan 1 GU Zheng-qi 1,2 ZHANG Sha1
Aiming at harsh driving mining road,road surface excitation is an important factor in the research of mining dump truck  ride comfort. Combined with rigid-flexible vehicle model ,this paper proposes that using BP neural network which is optimized by genetic algorithm to identify the mining road, prediction ability are improved greatly compared with standard BP network.The accuracy of the method is verified through vehicle road test. Compared with simulation results of ride comfort under common C-class and D-class roads, the  model simulation accuracy based on identification road is increased by 12.3%. Through the establishment of Kriging approximation model,the structure parameters of hydro-pneumatic suspension and seat are optimized by multi-island genetic algorithm, which makes the root mean square value of the seat acceleration as optimization objective and makes the sprung mass and tire stiffness damping as uncertainties. After optimizing, the value is descended by 37.4%, which achieves the purpose of improving the ride comfort.
2015 Vol. 34 (13): 24-30 [Abstract] ( 171 ) HTML (1 KB)  PDF (2653 KB)  ( 121 )
31 The intelligent diagnosis model research of QGA-VPMCD
YNAG Yu LI Zi-zhu He Zhi-yi CHENG Jun-sheng
Aiming at the defects that only one single model was selected during the variable predictive model-based class discriminate (VPMCD) classification method, an intelligent diagnosis model quantum genetic algorithm - variable predictive model-based class discriminate (QGA-VPMCD) is presented. The optimal weight matrix is used to comprehensively consider the effect of each diagnosis model of classification results in this model. Firstly, multiple subordinate variable predictive models (SVPMs) can be established through samples training. Secondly, intelligent quantum genetic algorithm is used to acquire the weights of each SVPM and the optimal weight matrix is obtained. Finally, optimal weights matrix is exploited to get optimal feature variables predictions by weight fusion for the values, which are predicted by the SVPMs for the test samples, and fault types are identified according to the minimum error square sum which is regarded as discrimination function simultaneously. The analysis results from the vibration signals of rolling bearings show the effectiveness of the proposed model. 
2015 Vol. 34 (13): 31-35 [Abstract] ( 244 ) HTML (1 KB)  PDF (1302 KB)  ( 433 )
36 Singularity and chaos of nonlinear galloping for an iced transmission line
HUO Bing1,2 LIU Xi-jun 1,2 ZHANG Su-xia 1,2 LIU Peng1,2
A three degree-of-freedom continuous dynamic model for an iced transmission line is proposed for describing the coupling of in-plane, out-of-plane and torsional vibrations, which is built on the basis of Hamilton principle with the consideration of geometric and aerodynamic nonlinearities. Galerkin procedure is applied to spatially disperse the partial differential governing equations. Together with average method, the bifurcation equation is derived from the average equations. The relevance of the bifurcated, unfolding and physical parameters is established, in which the bifurcated and unfolding parameters are separated and decoupled. Transition sets and their corresponding regions of original physical parameters are then made on the bifurcation equation by employing the singularity theory. The topological structures of bifurcated curves in different regions are presented, where saddle nodes and jumping phenomenon are found in certain regions. Numerical procedures are then implemented in the stable and jumping regions, respectively. The bifurcated diagrams obtained by numerical calculations are consistent with those derived by theoretical analysis, where periodic and chaotic solutions are observed, providing theoretical support to practical engineering.
2015 Vol. 34 (13): 36-41 [Abstract] ( 232 ) HTML (1 KB)  PDF (2103 KB)  ( 425 )
42 Vibration Self-synchronous Study of Wind Turbine Blade Single-point Fatigue Loading Test System#br#
ZHANG Leian123 WANG Zhongbin2 LIU Weisheng3 HUANG Xuemei1
For the self-synchronous vibration phenomenon in the process of the single-point fatigue loading test of wind turbine blade, the mathematical model of the single-point fatigue loading system based on LaGrange equation was established and the influence factors of the self-synchronous vibration phenomenon were obtained. Applying the phase plane method, the vibration system is converted into an autonomous system. Then the vibration system’s simulation model was built with Matlab/Simulink and the basic law of the self-synchronous vibration phenomenon in different initial phase was obtained. At last, a set of single-point fatigue loading test equipment which was used to test the accuracy of the mathematical model and simulation model was set up. The experimental results shows that under the premise of load source rotary drive frequency the same as the blade’s natural frequency, the self-synchronous vibration phenomenon occurs when the initial phase difference is less than   and in this state, the amplitude of blade is the largest and constant; when the initial phase difference is  , the self-synchronous vibration phenomenon is weak, and the amplitude of the blade gradually stabilizes at a low value after a period of time; when the initial phase difference is   , the self-synchronous vibration phenomenon do not occur and the amplitude of blade is disorder. The above conclusion provide theoretical basis for the control algorithm of fatigue loading test.
2015 Vol. 34 (13): 42-47 [Abstract] ( 145 ) HTML (1 KB)  PDF (1812 KB)  ( 364 )
48 Simulation Analysis of Multiaxial Heavy Vehicle Dynamic Load Characteristics under Bilateral Tracks’ Road Excitation
Liu Xiangyin Chen Yang Gao Pan Liu Dawei
In order to study the dynamic load characteristics of multiaxial heavy vehicle under bilateral tracks’ road excitation，the random road surface in spatial domain was simulated through harmonic superposition method of rational function power spectral density(PSD), and a rigid-flexible coupling virtual prototype vehicle was established. Then a ride dynamic model of multiaxial heavy vehicle under bilateral tracks’ spatial domain road excitation was established, and the vehicle tire normal force and tire normal dynamic load coefficient were computed. Simulation results indicated that, comparing with the single tracks’ road excitation, the value and change law of normal forces on the both sides of each axle’s tires under bilateral tracks’ road excitation were not the same, and maximum value of tire normal force appeared in a different location; The value and change law of normal dynamic load coefficient of each axies’s tires were completely different in different driving speeds，the front-mid axles’ tire normal dynamic load coefficient was minimum, the mid-rear and rear axles’ tire normal dynamic load coefficients were maximum. The research results could provide the basis for the calculation of vehicle tire dynamic load and verification of dynamic response of road surface.
2015 Vol. 34 (13): 48-52 [Abstract] ( 256 ) HTML (1 KB)  PDF (2116 KB)  ( 676 )
53 Surge analysis and active-passive control of central driven pure electric vehicle
YU Peng1,2，ZHANG Tong1,2,3， WANG Xiao-hua1,2, GUO Rong 1,2
Take a typical pure electric vehicle as object, analyzes its transient surge problem and control methods. Firstly, according to the constant mesh characteristics of the drive system, whole vehicle model was established considering motor rotor- gear transmission system, mechanism of surge phenomenon and transfer path analysis was derived. Then, from the perspective of the power transmission system, feed forward- feedback active control simulation based on the simplified model and parts of experiment were conducted. On this basis, optimization of the power train mount system was carried out from the facet of passive control. Finally, the simulation effect of the active- passive integrated control was validated based on whole vehicle platform. Results show that the whole vehicle model is suitable for the simulation and control of the electric vehicle’s surge problem; the active and passive combined control method can improve body surge situation, reduce the dynamic reaction force of mounting point and improve the ride comfort of vehicle.
2015 Vol. 34 (13): 53-59 [Abstract] ( 274 ) HTML (1 KB)  PDF (2338 KB)  ( 520 )
60 Numerical Simulation of Hull Grillage Response Under Blast Loading Based on the RKDG Method
YU Fulin GUO Jun YAO Xiongliang REN Shaofei
In order to simulate the characteristics of far field air explosion shock load, the discretizations of Euler equations were solved by RKDG method. The numerical model was established and far field air explosion shock wave load characteristics were simulated. The results were compared with the empirical formula. The density and pressure distribution of high pressure shock wave with large discontinuity were simulated with Fortran program. Combined with LS-DYNA, impulse responses of hull plates under shock load are simulated. The results indicate that the plastic deformed shape profiles along the stiffener direction, and the plate shows local dishing deformation, and the response is inversely proportional to the distance from the explosion center.
2015 Vol. 34 (13): 60-65 [Abstract] ( 187 ) HTML (1 KB)  PDF (2138 KB)  ( 188 )
66 Fault feature enhancement method based on multiscale orthogonal PCA-LPP manifold learning algorithm
Zhang Xiaotao, Tang Liwei, Wang Ping, Deng Shijie
Aiming at the feature enhancement problem of gearbox fault acoustic emission signals, a novel method based on multiscale orthogonal PCA-LPP manifold learning algorithm is proposed in this paper by considering the global distribution variance enhancement of PCA and the local nonlinear characteristics enhancement of LPP, and the redundant information between projection components were eliminated by orthogonal treatment. In the processing results of gearbox fault acoustic emission signals, on the one hand fault lines in envelope spectrum was more clearly, on the other hand, the eigenvectors of fault signals was constructed by wavelet packet energy entropy, the fault identification rate was increased obviously, and it could reach 93.75%.
2015 Vol. 34 (13): 66-70 [Abstract] ( 242 ) HTML (1 KB)  PDF (1532 KB)  ( 133 )
71 Fault Diagnosis of Multi-information Fusion by SVM & Improved Evidence Theory
XIANG Yang-hui, ZHANG Gan-qing, PANG You-xia
To comprehensively reasonably utilize much feature information of the equipment to improve the accuracy of the fault diagnosis, a method of multi-information fusion fault diagnosis is proposed which is based on support vector machine(SVM) and improved evidence theory. It gets the reliability of the local diagnosis evidence of each SVM to every failure mode by the confusion matrix, by which gives different weight coefficient. The basic probability assignment that is constructed by hard output decision matrix from the local diagnosis of each SVM, which effectively combines SVM and improved evidence theory in multi-information fusion fault diagnosis. The experimental results show that the weighted fusion treatment of the local diagnosis evidence from each SVM can significantly reduce the conflict between the local diagnoses, and that the proposed method can effectively improve the accuracy of fault diagnosis.
2015 Vol. 34 (13): 71-77 [Abstract] ( 257 ) HTML (1 KB)  PDF (1384 KB)  ( 477 )
78 Numerical Simulation of Gun Bore Damage During Engraving Process of Driving Band
Guangsheng Liu1,2，Heyang Sun2，Wei Zhou3
A Damage mechanics finite element numerical computation method was established based on HLC microscopic damage model to solve the problem of damage, crack initialization and growth inside bore during the firing process, which combines completely implicit stress renewing algorithm and explicit finite element computation. The method embeds the damage model into the finite element software ABAQUS/EXPLICIT module through VUMAT subroutine. The damage and failure process of the bore surface was simulated numerically during multiple rounds of firing. The law of the barrel material performance changing with the number of firing rounds was analyzed during the engraving process of the driving band and compared with the experimental results. It is proved that HLC microscopic damage model can show the complicate damage behavior and predict the cracking defect, which provides a reference for safety design of the gun barrel.
2015 Vol. 34 (13): 78-82 [Abstract] ( 159 ) HTML (1 KB)  PDF (1456 KB)  ( 217 )
83 Tool point FRF prediction researches of spindle-holder-tool system
WANG Erhua 1 WU Bo2 HU Youmin2 WANGJun 2 YANG Shuzi 2
Tool point frequency response function (FRF) is a prim need for constructing the stability lobe diagrams. Based on Timoshenko beam theory considering rotary inertia and shear deformation, all components of the spindle-holder-tool assembly are modeled as multi-segment Timoshenko beams. This study proposed an analytical method for obtaining the tool point FRF of a given combination by using transfer matrix and receptance coupling approaches. Compared with the calculation results of mode superposition method, the algorithm proposed is verified. The new prediction method can help to obtain the tool point FRFs of machine tools more precisely and quickly, so more accurate stability lobe diagrams can be achieved, and it can lay a foundation for ensuring the stability of high speed cutting processes.
2015 Vol. 34 (13): 83-88 [Abstract] ( 396 ) HTML (1 KB)  PDF (1252 KB)  ( 765 )
89 Acoustic Characteristic Analysis and Experimental Study of Centralized Driving Electric Vehicle
FANG Yuan1,2 ZHANG Tong1,2,3 YU Peng1,2 CHEN Feifei 1,2 GUO Rong1,2
The main noise sources of electric vehicle were analyzed, and then a vibration and noise experiment was conducted in order to investigate the generating mechanism and characteristics of electric vehicle noise. Spectral analysis, order analysis and partial coherence analysis are used to not only analyze the frequency characteristics of auxiliary system and compare vibration and noise characteristics of the electric powertrain between the coasting down condition and driving up condition respectively, but also clarify the contributions of powertrain noise on the vehicle. The research provides experimental support for the NVH optimation of the electric powertrain.
2015 Vol. 34 (13): 89-94 [Abstract] ( 835 ) HTML (1 KB)  PDF (2351 KB)  ( 344 )
95 Partitioned coupling scheme based numerical simulation platform for wind-induced vibration of tall buildings
Zheng De-qian1,2，Gu Ming2，Zhang Ai-she3
In this paper, a numerical simulation platform for fluid-structure interaction (FSI) problems of tall building structures was constructed by secondary development for commercial codes Fluent and Ansys. Conventional partitioned coupling scheme, equipped with subcycles for the fluid field calculation, was adopted in present study. The user defined functions (UDF) were used to implement mesh updating for the fluid field, and the matching & data transferring for the non-matching meshes on the coupled boundaries of the building structures. Large eddy simulation technique and parallel computation method was adopted to solve the fluid field accurately and efficiently, based on UDF and Scheme programming. The Ansys parametric design language (APDL) was programmed to solve the structural motions. Visual C++ programming was applied to mutual calling among modules of present solution procedure. Wind-induced vibrations of a square section tall building immersed in atmospheric boundary layer were numerically investigated by using present method. The simulated results were compared with those of aeroelastic model wind tunnel experiment and previous numerical simulation. By comparison of the simulated results with and without considering FSI, aerodynamic damping effect on wind-induced vibration of the building was analyzed. The results show that present method is verified to be applicable in numerically solving wind-induced aeroelastic responses of tall building structures.
2015 Vol. 34 (13): 95-100 [Abstract] ( 200 ) HTML (1 KB)  PDF (2642 KB)  ( 150 )
101 Study on Thermal Modal Test Method of a Wing Structure Considering Aerodynamic Heating
LIU Hao LI Xiaodong YANG Wenqi SUN Xiasheng
It is important to investigate the thermal modal test of wing structure in the design and flight of the modern hypersonic flight vehicles. The thermal modal test system considering aerodynamic heating is founded. The temperature control parameters depended on transient temperature field calculated by numerical analysis, are used to simulate the transient thermal environment. The temperature changing with heating time is measured, that validates the precious of temperature control. The modal frequency auto-tracing method is founded by combined the intelligent PID (Proportion Integration Differentiation) control technology with the traditional phase resonance method, that expands the traditional phase resonance method into the modal parameters identification of time-dependent structural dynamics system. The modal frequency auto-tracing method has been used to measure the first four thermal modal frequencies of a triangular wing structure in a thermal modal test. The test results are well agreed with the results of numerical calculation by FEM (Finite Element Method), which indicates that the modal frequency auto-tracing method of time-dependent modal parameters identification is accurate and realizable. In addition, the identification results under uniform temperature distribution thermal structure have been measured, that are also well agreed with the results of the numerical computation. The reason of modal frequencies of time-dependent thermal structure changed with the heating time is discovered in the end of this paper, by comparing the identification results under transient temperature field with that under uniform temperature field.
2015 Vol. 34 (13): 101-108 [Abstract] ( 197 ) HTML (1 KB)  PDF (2079 KB)  ( 167 )
109 Probability seismic risk analysis of isolation equipment in seismic design codes 
XIONG Yan 1 WU Di 2,3 CUI Jie 2
The research of the evaluation of seismic performance of base-isolated structure mainly focus on the upperstructure above the isolation equipment at present. However, comparatively little research has been made on the seismic risk analysis of isolation equipment which needs to be perfected further more. The ratio of the horizontal displacement of the isolation equipment and the dimensions of the isolation device (effective diameter of bearing) has been used as the structural demand, and the horizontal displacement limit of the isolation bearing in 2010 Chinese Code for Seismic Design of Buildings (GB50011-2010) has been defined as division standard for reference of the limit states. Then probabilistic seismic demand model (PSDM) for the isolation equipment in the base-isolated structure was initially built, and the exploration of the probability seismic risk analysis of the isolation equipment in base-isolated structure has been performed. At last, a seven-story base-isolated reinforcement concrete (RC) structure which was built in disaster area was studied as an example. This designed model and method was used to evaluate the probability seismic risk of the isolation equipment in the base-isolated structure.
2015 Vol. 34 (13): 109-114 [Abstract] ( 240 ) HTML (1 KB)  PDF (1452 KB)  ( 186 )
115 The dynamic stability research of apricots orientation  during conveying
LUO Jian-qing1, WANG Chun-yao1
Established the apricots mechanics analysis model about apricots transporting situation in the directional device, made the motion simulation of rigid-flexible coupling delivery system by use of Matlab mathematical analysis software, and made the experimental verification The dynamic stability of apricots orientation process based simulation experiments to confirm the findings. The results of motion simulation showed that apricots made gradually pure rolling around horizontal diameter after entering delivery system random, And tend to be stable, orientation well.The state of apricots motion during conveying was described completely by differential equations of motion. The simulated results agree to the experiment,and verify the correctness of the theory of apricots orientation.
2015 Vol. 34 (13): 115-120 [Abstract] ( 200 ) HTML (1 KB)  PDF (2221 KB)  ( 268 )
121 The full-field vibration measurement based on binocular stereo vision and digital speckle images
CHEN Zhong1,2 CHEN Jiao-dou2
The paper studies the  three dimensional full-field vibration measurement related problems based on the 3D digital speckle correlation method(3D-DSCM). In this method, binocular high-speed cameras continuous collect speckle dynamic deformation images, matching of target points combined with digital speckle correlation method, the out-of-plant vibration displacement information changes over time can be obtained. In this paper, through the experimental study by comparison experiment of the steady-state responses of sine excitation and the parameters  (correlation function, area size and shape function) choose influence on measurement results. The results show that relative error of  vibration amplitude measured 50hz steady state incentives is less than 3.5%, the amplitude-frequency curve correlation coefficient is higher than 98%;Correlation function, area size,  shape functions have great influence on accuracy of calculation.
2015 Vol. 34 (13): 121-126 [Abstract] ( 349 ) HTML (1 KB)  PDF (2215 KB)  ( 867 )
127  Dynamic characteristics of the pile under horizontal vibration loading
HAN Hongxia1，2, CUI Wuwen3, LI Yurun2
Based on the theory of elastic wave propagation and the mixed boundary problem of radiant stress of circular, the dynamic stiffness and damping of soil around the pile under horizontal harmonic loads can be calculated by using Fourier expansion method, when considering the effect of pile partially separated from soils. Then by applying it to the infinitely thin horizontal layers theory of Novak, the stiffness and damping of the pile and the vibration amplitude level of the pile with the frequency curve are obtained. It is shown that, in the horizontal vibration loads, the dynamic stiffness of pile is smaller than other stiffness, and the horizontal displacement plays an important role in all displacement. The calculated results considering the influence of pile-soil partial separation are less than that of the other literature, which assumed the bonding of the pile with the soil, and are in good agreement with experiments. The calculated results are closer to the test values when the shear modulus of soils is measured by the static test.
 
2015 Vol. 34 (13): 127-132 [Abstract] ( 235 ) HTML (1 KB)  PDF (1469 KB)  ( 959 )
133 Investigation of Active Vibration Isolation on Nonlinear Diesel Two-stage Vibration Isolation System
XIAO Bin1, GAO Chao1, ZHANG Ai-ping1, LIU Zhi-gang2
 For diesel two-stage vibration isolation system, when considering that heavy nonlinearity of the secondary path influence dynamical system modelling, vibration analysis as well as active control strategy designing and its control performance, in this paper a hybrid adaptive control strategy is presented by integrating adaptive notch filter algorithm with Model Reference Adaptive Inverse Control with Pre-Compensator (PCMRAIC). In active vibration isolation experiment of diesel two-stage vibration isolation system, based on decoupling Hammerstein nonlinear system and analyzing the Generalized Frequency Response Functions (GFRFs), linearized reference models and phase curves of the secondary path were yielded, and then the hybrid adaptive control strategy was investigated, whose results showed that, the linearized reference model that approximated the aimed nonlinear system can be employed to realize excellent linearization of system and to provide accurate phase curves of the secondary path, therewith the linearized reference model and FIR model of its phase curve fitting codetermine performance of the hybrid adaptive control strategy. In addtion, the results of active vibration isolation experiment were compared with vibrational energy modeling, which showed that the optimal isolation effect in vibrational energy level is obtained only when to eliminate nonlinarity and consequently to suppress harmonic vibration of the system.

 
2015 Vol. 34 (13): 133-139 [Abstract] ( 237 ) HTML (1 KB)  PDF (1823 KB)  ( 229 )
140 Unstructured zero-order energy finite element method for coupled plate structures
ZHOU Hong-wei CHEN Hai-bo WANG Yong-yan
Base on the governing equations of Energy Flow Analysis (EFA), meshing plates by triangles, an unstructured zero-order energy finite element method (uEFEM0) is developed. A procedure of calculate the L-shape plates and a simplified vehicle shell was presented, in which both bending and in-plane wave fields were considered. The proposed method was used to predict the distribution of energy response. To confirm its validity, Energy Finite Element Method (EFEM) and Statistical Energy Analysis (SEA) were employed to simulate the same structures, and the results show a good agreement. For simulating plates vibrating in high frequency, it is necessary to considering not only bending wave field but also in-plane wave fields, since the level of in-plane wave energy could be close to that of bending wave energy.
2015 Vol. 34 (13): 140-145 [Abstract] ( 181 ) HTML (1 KB)  PDF (1906 KB)  ( 204 )
146 A two-stage method for structural damage identification using the proportional damage model
ZHAO Jian-hua 1 ZHANG Ling 1 SUN Qing 2
In order to improve the efficiency of structural multi-damage identification, a two-stage method is presented for the identification and quantification of damage in this paper. In the first stage, a normalized modal strain energy based damage index is used to precisely determine the damage locations. The modal strain energy is calculated using the measured modal data and element stiffness matrix extracted from the finite element model. In the second stage, a matrix condensation approach in conjunction with a proportional damage model is then employed to derive the equation of quantifying the damage extent on the basis of damage location. Subsequently, the least-squares technique is used to solve for the unknowns of damage extent. To demonstrate the effectiveness of the proposed approach, numerical study has been carried out on a six-bay planar truss structure. The simulation results indicate that the proposed method is capable of identifying the location and extent of damage accurately with a certain noise level.
2015 Vol. 34 (13): 146-151 [Abstract] ( 214 ) HTML (1 KB)  PDF (1209 KB)  ( 357 )
152 Study on parameters in the new bipedal model for analysis of walking loads
WANG Yihe，YANG Na
It has previously been shown that a bipedal model can be employed to simulate periodic human walking. Based on the model in ISO 5982 and bipedal model, a new bipedal model is introduced. The dynamic equation of human walking is established by means of the Lagrange equation. The mass, damping, stiffness matrices, and the force vector of the system were defined from these equations. Walking characteristics and energy change is studied. And the effects of stiffness, impact angle and walking speed are investigated. The results show that the new bipedal model can reproduce periodic walking cycle that consists of the single and double support phases. The total energy of the model is constant, which convert between the gravitational potential energy, kinetic energy and elastic potential energy. Variations in the leg stiffness, attack angle and walking speed had a substantial effect on the walking characteristics, and increase in leg stiffness had a small effect on the period and step length.
2015 Vol. 34 (13): 152-157 [Abstract] ( 246 ) HTML (1 KB)  PDF (2338 KB)  ( 134 )
158 Bit abnormal drilling condition recognition based on PCA – SVDD
Liu Gang1，Liu Chuang1，Xia Xiangyang1，Pei Chonglian1,CAI Peng2, ZHAO Shao wei3
In order to detect bit abnormal drilling condition quickly and monitor the cluster wells timely, establish bit abnormal drilling recognition model based on PCA—SVDD, according to the characteristics of normalized amplitude frequency of bit vibration signals. Extract the normalized frequency characteristics, which was irrelevant to real amplitude value, of each frame of the bit normal drilling signal, which can adapt to every different situations. Taking the feature vector of signals in normal working conditions whose dimension was reduced by PCA as training samples, a PCA—SVDD bit abnormal drilling diagnostic model was established .The result of real experiment data showed that this method can detect abnormal condition effectively.
2015 Vol. 34 (13): 158-162 [Abstract] ( 179 ) HTML (1 KB)  PDF (1793 KB)  ( 209 )
163 Wind Tunnel Test on the Effect of guy Pretension on Mechanical Properties of UHV Cross-Rope Suspension Tower-Line
Yu Deng-ke 1 Li Zheng-liang 1 Shi Jing-hua2 Yan zhi-tao1 Xiao Zheng-zhi1
The effect of guy initial tension on wind-resistant performance of the ±800kV direct current (DC) cross-rope suspension tower-line is investigated through an aero-elastic model test in a boundary layer wind tunnel. Three kinds of guy initial tensions (15%, 20%, and 25% of the ultimate stress) were selected. The results show that the changes of guy initial tension have a significant influence on mechanical properties of tower-line system under wind load condition. There is a nonlinear-relationship influence on tension in guys and compression in masts. Thus the guy initial tension should be selected optimally.
 
2015 Vol. 34 (13): 163-168 [Abstract] ( 304 ) HTML (1 KB)  PDF (1964 KB)  ( 502 )
169 Optimization Design of Muffler Based on DOE and Improved Simulated Annealing Algorithm
Zhang Jun-hong，Zhu Chuan-feng,Bi Feng-rong，Wang Jian， Li Zhong-peng
To improve the efficiency of muffler optimization，based on the effect of flow rate on the transmission loss numerical modeling of mufflers, whose parameters were analyzed by Latin hypercube design in experimental design (DOE), Combined with improved simulated annealing algorithm, the single objective and multi-objective optimization model were established respectively in the exhaust noise of peak frequency as the goal of transmission loss, then a research on muffler was launched. The result shows that the DOE method can effectively identify the parameters which affect muffler performance, and simplify the optimization model of muffler. The average velocity of the gas in muffler has great impact on the optimization results. The transmission loss of muffler corresponding to the peak frequency through single objective optimization can reach maximum, while multi-objective optimization can make overall optimization results better, and the maximum reduction of exhaust noise can be 31.73dB, which is better than the results of single objective optimization. This study provides a new way of optimization design of the muffler.
2015 Vol. 34 (13): 169-175 [Abstract] ( 204 ) HTML (1 KB)  PDF (1945 KB)  ( 324 )
176 Design and Characteristics of a Passive Constant Force Shock Absorber
ZHANG Chun-hui1, WANG Yu2, DU Jian-ye2, WEN Zhao-dong2
It is well known that the acceleration amplitude and the relative displacement amplitude of ships equipment acceptable are very small when they are subjected to a strong impact. Under this circumstance, none of the vibration isolator and the displacement restrictor could meet the shock isolation requirements of ship equipments. Therefore, a special shock absorber is necessary which could store and dissipate larger shock energy. Based on the optimal shock isolation theory, a passive constant force shock absorber is developed. The relation between stress of cam sliding rail and spring deformation is obtained. Furthermore, the numerical analysis related to the effects of rubber stiffness and damping ratio on shock isolation performance of the absorber is carried out. The results prove that in comparison with the equivalent linearity shock isolation system, the constant force shock absorber can obviously reduce the absolute acceleration amplitude and the relative displacement amplitude and effectively improve the impact resistance performance. The conclusions provide certain value for reference to the design and application of the constant force shock absorber.
Key words: constant force device; impact resistance performance; damping ratio
2015 Vol. 34 (13): 176-181 [Abstract] ( 183 ) HTML (1 KB)  PDF (1892 KB)  ( 363 )
182 Time effect experimental study of the concrete dynamic Mechanical property at high temperature
Li Hong-Chao1 Liu Dian-Shu1 Huang Yong-hui2 Liang Shu-Feng1 Li Ming-Hui1
The aim of this paper is to investigate concrete dynamic mechanical properties at high temperature. In order to determine the concrete specimen heating time in different temperature groups, adopt the ANSYS software to simulate the temperature field during the heating process. Impact loading experiments were carried out on concrete at high temperature and different heating time by using a 75-mm-diameter split Hopkinson pressure bar (SHPB) apparatus and temperature control device. The results show that C60 concrete has obvious temperature effect and time effect. The dynamic compressive strength rises at first and then falls with increasing temperature and achieves the maximum at about 200℃, the peak strain rises with temperature increasing; Under 100℃, 200℃, 300℃, 400℃ and 500℃ steady-state temperature fields respectively, with increasing temperature, the dynamic compressive strength decreases and the peak strain rises and the elastic modulus decreases, and in the 500℃ steady temperature field, when the heating time being greater than 190 min, the dynamic compressive strength is tending towards stability and no longer decreases.
2015 Vol. 34 (13): 182-188 [Abstract] ( 172 ) HTML (1 KB)  PDF (3163 KB)  ( 109 )
189 Seismic Response Analysis and Reasonable Seismic Resisting System Design for Interchange Ramp Bridge
Juhui Zhang1 Zhongguo Guan2
The mainline interchange ramp bridge on the Jiamin Elevated Route in Shanghai was taken as the research object, and the effects of curve radii and earthquake input directions on seismic response of ramp bridges were discussed. The results show that, the seismic response of ramp bridges with smaller curve radius (R=50m) is very complicated. A deviation of 20o to 30o in angle and a lower value of bending moment by nearly 10% to 20% are existed at the pier bottom along the tangential or normal direction of pier columns compared with that of along the worst earthquake input direction. While the seismic response of ramp bridges, whose curve radius is larger than twenty times of bridge width, is nearly consistent with that of the straight bridge. A simplified straight bridge model can be used in the modeling of larger curve radius ramp bridges. Base on the new two-level seismic fortification criterion, the seismic performance of the ramp bridge was evaluated. It shows that it is easier to meet the strength requirements under E1 earthquake; while under E2 earthquake, both the fixed piers under the longitudinal earthquake input and the higher piers under the transverse earthquake input will be yield, especially shear failure is easily occurred in the lower fixed pier. Then the ductility seismic resistant system and the seismic mitigation and isolation system were respectively selected and applied for seismic design of the straight ramp bridge. The applicability of these two seismic systems is evaluated and the results show that only using one kind of seismic systems cannot meet the structural performance. It is suggested that the ductility seismic resistant system is applicable to area of the ramp bridge with tall piers, and the seismic mitigation and isolation system is more applicable to the area of the ramp bridge with short piers.
2015 Vol. 34 (13): 189-194 [Abstract] ( 168 ) HTML (1 KB)  PDF (2013 KB)  ( 147 )
195 Parameter Research of Joints Stiffness in a Rocking Reinforced Concrete Frame
LU Liang 1 LIU Xia1?CHEN Jun Jie2
Parameter research of joints stiffness in a rocking reinforced concrete frame is performed in this paper. Firstly, the finite element model of the rocking reinforced concrete frame is established and verified by the shaking table test. In addition, the method of time-history analysis is performed to investigate the dynamic responses of structure under different conditions, i.e., relative stiffness ratio of nine kinds along with ten earthquake waves. Finally, the peak inter-story drift and peak inter-story shear force of structure are studied using ten different ground motions for time-history dynamic analysis, and are compared by two coefficients; the inter-story drift amplification coefficient and the base earthquake-reduction coefficient. Consequently, the results show that the suitable range of relative stiffness ratio is 0.01 to 0.25.
2015 Vol. 34 (13): 195-199 [Abstract] ( 231 ) HTML (1 KB)  PDF (1782 KB)  ( 400 )
200 Influence of curing time to compressive properties of cemented sand similar materials
Yuan Pu1,2, Xu Ying1,2
In order to investigate the reasonable curing time of similar material, reduce the cycle time and accelerate the progress of physical similar model test, static uniaxial compression test was conducted for cemented sand similar material with 4 kinds of proportions in 3 kinds of curing times. Moreover, impact uniaxial compression test was also carried out by split Hopkinson pressure bar apparatus. The research shows that with the hydration reaction of cemented material in similar material proceeding, both static and dynamic uniaxial compressive strength for 4 kinds of cemented sand similar material increases with curing time growing. And the increase rate from 7d to 14d is fast, while the increase rate from 14d to 21d is slow. So the reasonable curing time for cemented sand similar material is 14d. Under the condition of test strain rate, both the dynamic increase factor for compressive strength and dynamic peak strain of cemented sand similar material decrease gradually with curing time growing. The smaller the sand-cement ratio, the more the cemented material in similar material is, then the bigger the static and dynamic uniaxial compressive strength is and the smaller the dynamic increase factor for compressive strength is.
2015 Vol. 34 (13): 200-204 [Abstract] ( 197 ) HTML (1 KB)  PDF (1665 KB)  ( 166 )
205 Frame supported multi ribbed composite wall structure elastic-plastic finite element analysis based on vibration test
HE Yu-yang1, YUAN Quan1
In this paper, the frame supported multi ribbed composite wall structure vibration table test basis, using finite element software ABAQUS, establish the nonlinear finite element model of the structure, and the earthquake response of the structure under several typical working condition test of numerical simulation calculation, selection of vibration type, representative of the natural frequency of vibration, acceleration, inter story displacement angle, structure failure modes analysis results, the results are compared with experimental results. The analysis results show that the numerical simulation and shaking table model test agree well with the established finite element model can reflect the frame supported multi ribbed composite wall structure of the basic dynamic characteristics, using the finite element model can not only improve the efficiency of seismic analysis of building structure, to make up for the lack of shaking table test, is also more conducive to analysis the seismic performance and energy dissipation mechanism, so as to prove the rationality and reliability of the numerical simulation, and conclude that the dynamic properties of the structure and the basic rules of the elasto plastic seismic response, and provides a basis for the future of the structure of the engineering practice and scientific research.
2015 Vol. 34 (13): 205-210 [Abstract] ( 204 ) HTML (1 KB)  PDF (3683 KB)  ( 390 )
211 Research for the smart micro-displacement active vibration isolation system
WANG Chang-song, LIANG Sen, WEI Liming
In order to isolate the vibration for precision instrument, a smart micro-displacement active vibration isolation system is presented in this paper, which is consisting of the PZT actuator, sensor and controller. Based on NI PXI data acquisition system and BK vibration exciter, the hardware experiment platform for micro-displacement active vibration isolation control system is built in detail. The related principles of active noise control technology are applied to the active vibration control. The data acquisition and F-XLMS control algorithm program are developed by using LabVIEW. The experiment research is carried out under sine, sweep and random excitation signal, respectively. The result verifies the validity of the micro-displacement active vibration isolation system. This investigation will provide an important theoretical foundation for the micro-displacement active vibration isolation system designing of precision instruments and micro-nano equipment.
2015 Vol. 34 (13): 211-216 [Abstract] ( 232 ) HTML (1 KB)  PDF (2584 KB)  ( 209 )
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