28 April 2023, Volume 42 Issue 8
    

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  • ZHANG Wukun1,2,TAN Yonghua2,3,GAO Yushan1,2,ZHAO Jian1,2,XIONG Jian4,WANG Jun1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 1-19.
    Abstract ( 562 ) Download PDF ( 266 )   Knowledge map   Save
    Periodic porous structure has been gaining more and more attentions to many researchers because of its excellent mechanical properties such as lightweight, high strength and multi-functional characteristics such as vibration suppression and energy absorption. The research on the dynamic mechanical properties of lightweight porous structure and its filled hybrid or composite structures were reviewed in this paper in recent years, such as energy absorption and vibration. Firstly, the cells and structures forms of lightweight porous structures with obvious advantages in vibration damping and impact resistance were summarized. Secondly, in terms of energy absorption performance, the research results were concluded from three aspects: quasi-static loadings, impact loadings and their applications. Thirdly, according to the vibration characteristics, the research work on vibration analysis, vibration suppression or isolation and the applications of vibration characteristics were also introduced. Finally, the future development directions were prospected, including dynamic mechanical model of porous structure based on additive manufacturing, fatigue and damage tolerance performance of porous structures, dynamic mechanical properties of porous structures under multiple fields and loadings, the design methods and performance characterization of porous structures under impact and vibration resistance, and the design methods of porous structure-material-function-integration(MSFI) for engineering applications and so on.
  • SHI Junlei1,2,3,DING Zhe1,2,3,ZHANG Lei1,2,3,ZHANG Yan1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 20-27.
    Abstract ( 272 ) Download PDF ( 150 )   Knowledge map   Save
    Calculating the first-order derivatives of Power Spectrum Density (PSD) function with respect to design variables is a prerequisite for random responses when gradient-based optimization algorithms are adopted. Unlike viscous damping model, which assumes that the damping force is proportional to the velocity, the damping force of non-viscous damping model depend on the past history of motion via convolution integrals over some suitable kernel functions. Therefore, the non-viscous damping model is more accurate to modelling the energy dissipation behaviors of viscoelastic materials. This paper considers the design sensitivity analysis of PSD function for non-viscously damped systems subjected stationary stochastic excitations. The governing equations of the non-viscously damped system under stationary random excitations are transformed into a deterministic harmonic response problem based on Pseudo-Excitation method (PEM). The expressions of the first-order derivatives of the PSD function is derived by direct differentiate method. Three numerical methods, namely complex-mode based first- and second-order approximation method (PEM-FAM, PEM-SAM) and real-mode based iterative method (PEM-IM), are proposed to calculate the sensitivity of the PSD function. The computational accuracy and efficiency of the three methods are compared by two numerical methods. The results indicate that the PEM-IM would be the best candidate to compute the sensitivities of the PSD function of non-viscously damped systems, especially for large-scale problems.
  • ZHAO Weiyi,CHEN Peihan
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 28-37.
    Abstract ( 374 ) Download PDF ( 320 )   Knowledge map   Save
    The impact resistance of half steel-concrete composite slabs (HSC slabs) is very excellent, which can effectively resist rockfall impact. Under the premise of meeting the requirements of relevant codes, HSC slabs can be designed to reduce the deformation of HSC slabs under rockfall impact, so as to maximize the safety of infrastructure and people in mountain areas. To quickly and accurately deal with the complex nonlinear relationship between HSC slabs deformation and design parameters, the prediction models of HSC slabs maximum deformation under impact are established based on three machine learning algorithms, and the model is verified by finite element results. On this basis, taking the maximum deformation, self-weight and cost of HSC slabs under rockfall impact as the optimization goal, the genetic algorithm is used to optimize the design of a HSC roof slab in a mountain building, and the optimal solution set of design parameters such as thickness and connector size of HSC roof slabs is solved. The research results show that the gaussian process regression (GPR) model has the highest prediction accuracy for the deformation of HSC roof panels, which can replace the complex and time-consuming finite element calculation, and effectively improve the calculation efficiency of the objective equation, and the final optimization results give a variety of optimization schemes, which can effectively reduce the deformation of HSC roof slabs, and provide a reference for engineering design.
  • LIU Tao1,2,3,ZHANG Shunqi1,LIU Qingyun2,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 38-50.
    Abstract ( 242 ) Download PDF ( 91 )   Knowledge map   Save
    The piezoelectric parameters (piezoelectric stress, strain and dielectric parameters) of piezoelectric materials are sensitive to temperature, and directly affect the performance of piezoelectric smart structures. In order to accurately analyze the nonlinear mechanical behavior and nonlinear active control of functionally graded plates (FGPs) with surface-bonded piezoelectric layers in thermal environment, firstly, the influences of temperature on piezoelectric parameters are introduced into the traditional linear piezoelectric constitutive equation. The nonlinear isogeometric analysis (IGA) model of piezoelectric functionally graded plates (PFGPs) is established based on the first-order shear deformation theory (FSDT) and Von Kármán theory, and the correctness and effectiveness of the model are verified by relevant numerical examples. Secondly, the free vibration and nonlinear static bending of the plates under various loads are analyzed. Finally, the displacement-velocity feedback control method is used to study the nonlinear active control of the plates. The results show that the temperature dependence of piezoelectric parameters have influences on the free vibration, nonlinear static bending response and nonlinear active control effect of piezoelectric functionally graded plates, and the influences are related to the thickness of piezoelectric layers, gradient index n and temperature.
  • TONG Yu,TIAN Zhongliang,QIAO Zhaoyang,LIU Menglong,SUN Yanhua
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 51-61.
    Abstract ( 222 ) Download PDF ( 86 )   Knowledge map   Save
    An automatic balance control algorithm based on improved adaptive notch filter (ANF) was proposed to suppress the unbalance vibration of the rotor supported by active magnetic bearings without the information of the rotation speed. Firstly, the structure and principle of the typical ANF were introduced, and the method to select the control parameters was discussed. In order to solve the instability problem of the system in low speed range which caused by the embedded ANF in the closed-loop system of the magnetic bearings, an optimal phase compensator was presented and the performance of the ANF was improved further while keeping the stability of the whole system in the full speed range. Then, a rotor speed estimator was designed according to the phase relationship between the input and output signals of the ANF. The contradiction between the convergence speed and the estimation accuracy was balanced through normalization of parameters of the estimator and the variable gain algorithm. Thus the convergence property of the estimator was consistent at different rotation speed. Finally, the proposed method was verified by simulation and experiments. The results showed that the speed estimator can quickly and accurately estimate the rotor speed from the displacement signals of the rotor, and the ANF can effectively eliminate the synchronous components in the control currents and the bearing forces. This method can realize the automatic balance control without speed sensor. It not only simplifies the bearing structure but also reduce the cost of the system, and has a good prospect in the industrial application of magnetic bearings.
  • GUO Jianbin1,SHEN Yongjun1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 62-68.
    Abstract ( 231 ) Download PDF ( 76 )   Knowledge map   Save
    The dynamics and stability for the primary resonance of the van der Pol-Mathieu equation with fractional-order differential term under harmonic excitation were studied. At first, the approximate analytical solution of the equation was obtained by the averaging method, and the numerical method verified the accuracy of the analytical results. Moreover, the amplitude-frequency equation of the system steady-state response of the was established, and the stability conditions for the steady-state response were obtained through using Lyapunov theory. On this basis, the effects of the parameters of the parametric excitation, self-excitation and fractional-order differential term on the amplitude-frequency characteristics of the system were analyzed. The results show that: The change of the parameter-excited coefficient mainly affects the response amplitude and resonant frequency range of the system. The change of the self-excitation coefficient mainly affects the response amplitude and multi-value property of the system. The change of the coefficient and order of the fractional-order differential term has a double-regulation effect on the dynamic behavior of the system.
  • CHEN Yuliang1,2,LI Hao1,CHEN Zongping1,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 69-78.
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    In order to study the restoring force model of solid-web steel reinforced concrete columns under the effect of composite torsion, 9 solid-web SRC columns were tested by quasi-static loading test by considering the three main factors of torsion bending ratio, axial compression ratio and shear span ratio. The torque-torsion angle skeleton curves and the hysteretic curves were obtained, and the influence laws of the torsion hysteretic performance under different torsion bending ratios, axial compression ratios and shear span ratios were analyzed. Based on the experimental torque-torsion angle skeleton curves and the hysteretic curves, the trilinear model of skeleton curve with the yield point, peak point and failure point as characteristic point was proposed, while the hysteretic laws were simplified; the restoring force model under composite torsion of solid-web SRC column was established. The results show that with the increase of torsion bending ratio, the failure mode of specimens changed from bending failure to torsional failure. The torsion resistance of solid-web SRC columns is most influenced by torsion bending ratio. The torque-torsion angle skeleton curves’ calculation results under different torsion bending ratios, axial compression ratios and shear span ratios are in good agreement with the experimental ones. The proposed torsional restoring force model considering the influence of unloading stiffness degradation also preferably predicts the torsional hysteretic curves of solid-web SRC columns. The results can provide a reference for elastic-plastic seismic response analysis of such structures under complex stress states.
  • CHEN Zhizhao1,LIU Zhouqiang1,2,XU Yan1,LIANG Bo3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 79-86.
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    Integrated viaduct can accommodate urban viaduct with rail transit lines,saving construction space and helping relief traffic pressure, and thus has received increasing attention and applications in urban transportation planning in recent years. However, due to the lack of speciallized seismic design specifications, the seismic fortification standards, performance objectives and seismic design methods of such bridges need to be studied urgently. Taking an actual bridge as the background project, reasonable seismic fortification standards and performance objectives are proposed, and the influence of the track on the dynamic characteristics and elastic seismic response of the structure is then studied. The nonlinear fiber model is further adopted to study the influence of pier longitudinal reinforcement ratio, pier-beam stiffness ratio, and height ratio of upper and lower piers on the pier’s yielding sequence. The research shows that the track increases the longitudinal stiffness of the structure and the seismic response of the lower pier and the cap beam, and the ductile seismic design should be adopted for the integrated viaduct, the cap beam should be designed as a capacity protected member, and the two-level performance objectives should be satisfied through reasonable design of pier-beam section stiffness, pier height and reinforcement ratio, ensuring that the structure produces an expected ductile failure mode subjected to earthquake shaking.
  • LI Jianhui1,ZHENG Ling1,DENG Jie2,LI Meiyu1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 87-95.
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    In view of non-uniform wavelength distribution and variable wave-number in Acoustic Black Hole (ABH) plates, a semi-analytical model based on the Improved Gaussian Expansion Method(IGEM) is proposed to analyze the flexural vibration of ABH plates. In the framework of the Rayleigh-Ritz method, Gaussian functions are used as basic functions to describe the displacement field around ABH plates. The scale factor of Gaussian functions is adjusted according to the variable thickness of the plate. Meanwhile, the distribution of Gaussian functions will be a function of the scale factor and the shape of the ABH plate. In this process, the scale factor is not a constant anymore as in traditional Gaussian Expansion method. Therefore, the displacement of the plate with different thicknesses can be described more accurately, and the separation of x direction and y direction in the integration process can be realized to improve the efficiency and accuracy in computation. The singularity of the mass and stiffness matrix can be avoided when Improved Gaussian Expansion Method is applied to ABH plates In this paper, a rectangular plate with ABH indentations, a circular plate with ABH indentations and a perforated plate with ABH indentations are taken account as examples. The results are compared with Finite Element method (FEM). Results show that the proposed method demonstrates  more accurate and less computation cost than the conventional Gaussian Expansion Method. This implies a potential application to predict the response characteristics of structures with thickness variation rapidly as ABH plates. 
  • YANG Xiaofeng1,HE Tao1,SHEN Yujie2,LIU Yanling1,ZHANG Ying3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 96-103.
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    In order to further enhance the vibration isolation potential of vehicle suspension using mechatronic inerter, a quarter dynamic model of vehicle mechatronic inertial suspension based on bridge electrical network structure was established, and deduced the output force expression of mechatronic inerter. According to the solution method of bridge network impedance, three basic bridge network structures were selected and compared with their corresponding series-parallel network structures. The analysis results show that under the same number of components, the bridge network can realize higher order impedance transfer function than the series-parallel network. Aiming at improving the comprehensive performance of vehicle suspension, the optimal parameters of several different structures of vehicle mechatronic inertial suspension were obtained by pattern search method. The simulation results under random road surface show that, with the same number of components, the bridge network has better vibration isolation effect than the vehicle mechatronic inertial suspension with series-parallel network, which provides a new method for the design of vehicle suspension system with mechatronic inerter.
  • ZHAO Yufen1,TIAN Ge1,WANG Yizhen1,SONG Leilei1,QI Changjian1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 104-110.
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    The ply scheme and molding process are important factors affecting the ballistic protection performance of ultra-high molecular weight polyethylene (UHMWPE) fiber composites. In order to evaluate influences of the factors on the bulletproof performance of UHMWPE fiber composites, a four-factor and three-level orthogonal table of ply orientation angle and three hot pressing process conditions including temperature, pressure, time was established based on the orthogonal test design, and 9 groups of ballistic limit experiments were carried out. The range and variance analysis of the experiment results show that the effect sequences of experimental factors on ballistic protection from strength to weakness were as follows: ply orientation angle, molding time, molding pressure and molding temperature. In addition, it is found that the ballistic impact energy absorption of [(0°/90°)2]2n and [(-45°/+45°)2]2n laminated composites was reflected in the cooperative energy consumption of multiple failure modes, while the ballistic impact energy absorption of [(0°/90°)2/(-45°/+45°)2]n quasi isotropic laminated composites was reflected in the energy consumption of single failure mode. Finally, considering the bulletproof performance and cost, the optimal combination was determined as follows: forming temperature of 120 ℃, pressure of 25MPa, time of 20min and ply angle of [(0°/90°)2]2n.
  • QIU Yikun1,ZHEN Wei1,ZHOU Changdong2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 111-118.
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    Due to the lack of multi-seismic defense lines, the high-rise concrete TV tower structures are easy to be damaged under the earthquake. The evaluation of the damage state of the structure after the earthquake is of great significance to evaluate the seismic performance and recoverability of the structure after the earthquake. In this paper, a new global damage model,defined by the ratio of the area enclosed by the IDA curves,based on the incremental dynamic analysis (Incremental dynamic analysis, IDA) method is proposed. The principle of structural damage state and the selection method of ground motion intensity measure are introduced, and it is proved that the overall damage value proposed in this paper increases monotonously with the increase of ground motion intensity measure. Taking Beijing CCTV Tower as an object, the applicability of this damage model and other damage models to the structure of high-rise concrete TV tower is studied. The results show that the model proposed in this paper solves the problem of local decline of damage evolution curves of other models. in addition, the shape characteristics of damage evolution curves of this model are more consistent with the brittle failure characteristics of TV tower structure.
  • ZHU Yungui,GUO Yu,ZOU Xiang,TIAN Tian,XU Wantong
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 119-125.
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    For the occasion when the fault characteristics of rolling bearings are weak and the installation of vibration sensors is limited, the fault characteristics are not easy to extract. In this paper, combined with the advantages of short signal transmission path and little interference of rotary encoder, this paper proposes a method for enhancing the fault characteristics of rolling bearings based on instantaneous angular speed (IAS) signal of rotary encoder. Firstly, the de-phasing algorithm (DPA) is used to suppress the strict periodic components such as the frequency conversion and its harmonics; secondly, the bearing fault impact component is enhanced by multi-point optimization minimum entropy deconvolution adjusted (MOMEDA); finally, the enhanced signal is analyzed in the spectrum to extract the bearing fault impact characteristics. The effectiveness of the proposed method is verified by simulation and measured data of bearing outer ring.
  • SUN Yujian1,WANG Zhongmin1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 126-133.
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    The transverse free vibration of a rotating viscoelastic rectangular plate described by fractional derivative constitutive relation is studied. Based on the plane problem of the plate, the Kelvin-Voigt two-dimensional constitutive relation with fractional derivative is obtained from the Kelvin-Voigt three-dimensional constitutive equation with fractional derivative. The differential equation of motion for rotating rectangular plate made of viscoelastic material with fractional derivative is established with Hamilton principle. Differential quadrature method is used to discretize the differential equations of motion and boundary conditions, and the complex eigen-equation of the system is obtained. The effects of fractional derivative order, width to length ratio, radius to length ratio and thickness to length ratio on the imaginary part of dimensionless complex frequency of the system are analyzed. The results show that with the increase of the rotational angular speed, the imaginary part (natural frequency) of the first three order dimensionless complex frequencies increases; with the increase of the fractional derivative order, the imaginary part of dimensionless complex frequency decreases; and the effect of each parameter on the third order imaginary part of the complex frequency is greater than the first and second order.
  • WANG Shuo,HUANG Jin’an,DAI Chenghao,CHEN Haibo
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 134-141.
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    In order to investigate the influence of axial force on the high frequency vibration of beam, the energy radiation transfer model of beam under axial force is established. For the Euler-Bernoulli beam with constant axial force, the wave number and group velocity affected by the axial force are introduced, the governing equation of energy density is established, and the kernel functions of energy density and energy intensity of the beam under axial force are derived. The real source strength is expressed by the input power calculated by the admittance method, and the virtual source strengths are determined by the energy balance equations at the boundaries. According to Huygens principle, the energy response of beam is obtained by the linear superposition of the direct field generated by the real source and the reflected field generated by the virtual sources. Finally, by comparing the results obtained by the energy radiation transfer method (RETM) with the analytical solution calculated by the wave propagation method, the applicability of the input admittance of infinite structure under the action of axial force is analyzed, the accuracy of the proposed RETM is verified, and the influence of axial force on the energy response of beam is also analyzed.
  • SU Yiyi1,ZHANG Liwen1,XU Qiping2,LIU Jinyang1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 142-151.
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    With regard to a kind of hyper-elastic pneumatic toothed soft actuator with planar bending deformation, a dynamic model of the two-dimensional multi-beam structure was established based on the nonlinear constitutive relationship and absolute nodal coordinate method (ANCF) considering the geometrical nonlinearity. The penalty method is used to model the soft contact problem between adjacent chambers, which considers multi-point contact and can avoid the mutual penetration between adjacent chambers, and can accurately simulate the variable topological process of adjacent chambers from no contact to full contact. Compared with the ANCF solid element model, the two-dimensional multi-beam model has lower computational cost, therefore it is more efficient. The precision of the proposed theoretical model was verified by pneumatic bending experiments and ABAQUS simulation. On this basis, the influence of the gravity on the configuration of soft actuator is studied, and the influence of the inflation rate and the final loading pressure on its dynamic response is analyzed.
  • WANG Xuejun,XIONG Jinjin
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 152-159.
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    In order to analyze the vibration during the working process of the ground rod auxiliary drilling rig and improve it. The simulation model of the ground rod auxiliary drilling rig is established and setting parameters, the modal analysis of the ground rod auxiliary drilling rig is carried out to obtain the natural frequency and mode shape of the whole machine, and the transient dynamics of the ground rod auxiliary drilling rig is carried out using the finite element analysis method. Through analysis, the vibration acceleration and frequency spectrum of the machine under different motor speed and different loads are obtained. Through the dynamic signal test of the whole machine, the vibration acceleration and frequency spectrum of each measuring point are obtained. The simulation results are in good agreement with the experimental results. The simulation and experimental results show that the motor speed has a great influence on the vibration characteristics of the ground rod auxiliary drilling rig, while the load has little influence on it. The vibration reduction optimization of the ground rod auxiliary drilling rig is carried out, and the vibration acceleration amplitude and stress strain of the ground rod auxiliary drilling rig before and after optimization are compared. service life.
  • WANG Dai1,2,CHEN Changhao1,ZHANG Hai1,2,LIU Zhongxian1,2,MENG Sibo1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 160-166.
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    For the possible damage risk of the tunnel passing through the underground utility tunnel under the gas explosion, firstly, the overpressure time history of utility tunnel is determined through the field gas explosion test of underground utility tunnel, then the overall three-dimensional finite element model of utility tunnel, soil and undercrossing tunnel is established, and the load is applied to the inner wall of gas tank of utility tunnel to calculate and analyze the dynamic response law of undercrossing tunnel. The results show that the measured peak overpressure of gas explosion is as high as 0.63Mpa, and the duration of overpressure at both rising stage and descending stage is about 0.1s; The vault area of tunnel lining is impacted first, and the lining displacement increases with the increase of time, while the lining stress reaches the maximum at the peak of overpressure. The Mises stress of parallel undercrossing tunnel can be more than 3.5 times than that of orthogonal undercrossing; With the increase of the distance between the tunnel and the utility tunnel, the dynamic response of tunnel, such as lining stress and vibration speed, decreases gradually, and the decreasing trend is more obvious for the case of orthogonal undercrossing; Comprehensively considering the influence of various factors, it is suggested that the orthogonal undercrossing tunnel should be considered preferentially, and the safe spacing for the undercrossing tunnel should be greater than 7m. The research results can provide some reference for the anti-explosion design of utility tunnel and the engineering design of undercrossing tunnel.
  • YU Anbin1,ZHAO Yinglong2,3,HOU Jiuxiao2,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 167-176.
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    In order to study the vibration transmission mechanism of underwater vibration isolator, the vibration coupling theoretical model of double-layer cylindrical shell with elastic connection and interlayer water is established by combining substructure admittance method, wave propagation method and four end parameter method. The model is divided into two substructures: inner and outer shell and the modified substructure composed of elastic connection. The influence of sandwich fluid is described by the matrix composed of structural stiffness and connection stiffness, the sound pressure of water medium in the inner shell is deduced, and the vibration transmission characteristics of underwater vibration isolator are studied. The results show that under the condition of interlayer water medium, the fluid loading effect of water medium in the inner shell acts on the inner shell and outter shell at the same time; The interlayer water between the inner and outer shells plays a "short circuit" role in the vibration transmission between the shells, which reduces the vibration damping performance of the vibration isolator, while has nothing to do with the interlayer thickness; In addition, compared with the rigid support connection, the underwater vibration isolator still has a certain vibration isolation effect.
  • ZHANG Shangrong1,LI Shihao1,LIU Liangkun2,TANG Xiang1,ZHANG Chi1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 177-185.
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    In order to solve the problem of seismic failure caused by co-frequency resonance of two adjacent structures, a damping control strategy for three adjacent structures is proposed. Based on Clough-Penzien spectrum, the corresponding stochastic extended state equation is derived by using single-degree-of-freedom and multi-degree-of-freedom mechanical simplified models, and the influence of parameters on the damping effect of three adjacent structures under different combinations is studied. Based on the principle of minimizing the total energy of structural vibration, the improved genetic algorithm is used to optimize the damping control scheme, and the number and location of dampers under the corresponding control scheme are obtained. The spectral model is input to analyze the inhibitory effect of the control scheme on the high-order response, and the damping control performance of the system under seven groups of ground motions is analyzed. The results show that the three adjacent structures can effectively solve the failure problem of damping control of the same frequency resonance of two adjacent structures, suppress the high-order response, and effectively reduce the seismic response, and have good robustness.
  • YANG Ziqian1,2,CHEN Qingjun1,2,SUN Xiangtao1,2,KONG Qingzhao1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 186-193.
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    Crack repairing receives increasing attentions for aging and damaged concrete structures. Real-time assessment of crack repairing process is of great significance to timely ensure the structural performance recovery condition in construction. An innovative technique for monitoring the process of crack repairing was presented, including a novel concrete implantable module design, a data fusion-based method to evaluate the repairing work. The designed module can be implanted into structure to actuate and receive multi-path stress waves using the embedded piezoceramic sensing elements array. The sampling data in different moments can be fused in the Minkowski distance for a comprehensive reflection of the repairing work. The finite element study reveals the characteristic of stress-wave propagation at the repairing crack interface. Relative energy and correlation coefficient fused by Minkowski distance are proposed to access the crack repair work, respectively; their feasibility to characterize the hydration process of repairing material is demonstrated via a three-dimensional model. Finally, an experimental study was conducted to verify the feasibility of the proposed technique using for monitoring the crack repairing process.
  • JIN Liu,ZHANG Jiangxing,LI Dong,DU Xiuli
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 194-205.
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    Based on ABAQUS finite element numerical calculation platform, considering the heterogeneity of concrete materials and the strain rate effect of reinforcement and concrete, a three-dimensional (3D) meso-scale numerical analysis model of Reinforced Concrete (RC) beam was established, and then the shear performance and size effect of RC beams under different strain rates and stirrup ratios were investigated. The results show that: 1) With the increase of strain rate and stirrup ratio, the shear bearing capacity will increase to varying degrees. 2) The nominal shear strength decreases with the increase of beam height, and there is a significant size effect phenomenon. 3) The increase of strain rate and stirrup ratio can both increase the nominal shear strength of RC beams and weaken the size effect of nominal shear strength. 4) The proposed static/dynamic shear uniform size effect law of RC beams considers the influence of size effect, strain rate effect and stirrup ratio at the same time, which can well predict the nominal shear strength of RC beams under static and dynamic loads, with certain accuracy and rationality.
  • SU Yixin,GONG Chenglong,ZHANG Danhong
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 206-214.
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    In this paper, a recursive sliding-mode dynamic surface control (DSC) law with a saturation handling module is designed for dynamic positioning (DP) of ships with the saturation characteristics of propellers, unmeasurable velocities and unknown external disturbances. A saturation handling module with smooth input and output characteristics is designed based on Gaussian error function to limit the output of the control law. A high-gain observer is constructed to estimate the unmeasurable velocities according to the position and heading angle information of the ship. And a recursive sliding mode DSC strategy is designed to enhance the non-fragility of the control law to the perturbation of system parameters. By properly choosing the Lyapunov function, the stability of the DP closed-loop control system and the ultimately uniformly boundedness of all signals are proved. Finally, the DP simulation analyses of a supply ship is carried out. The results show that the designed control law has a strong rejection ability to the external disturbances and a strong non-fragility to the perturbation of system parameters, which can ensure that the DP control system has a good dynamic quality and steady-state performance.
  • ZHENG Jinde,LI Jiaqi,PAN Haiyang,TONG Jinyu,LIU Qingyun
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 215-225.
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    Multi-scale dispersion entropy (MDE1D) is an effective nonlinear dynamics analysis method to measure the complexity characteristics of one-dimensional vibration signal, but it can only reflect the complexity characteristics in the time domain of the vibration signal, and cannot completely reflect the nonlinear dynamics information in the frequency domain of the vibration signal. To this end, two-dimensional time-frequency dispersion entropy (TFDE2D) is proposed based on the two-dimensional dispersion entropy (DE2D) to measure the time-frequency complexity characteristics of time series. Meanwhile, the traditional coarse-grained method is extended to two-dimensional multi-scale coarse-grained to reflect the complexity of the time-frequency distribution at different scales more completely, and the two-dimensional multi-scale time-frequency dispersion entropy (MTFDE2D) is proposed to measure the multi-scale complexity characteristics of the time-frequency distribution of vibration signal. On this basis, an intelligent diagnosis method for rolling bearings based on MTFDE2D and firefly optimized support vector machines is proposed to extraction of nonlinear features in rolling bearing fault diagnosis. Finally, the proposed method is applied to the analysis of experimental data of rolling bearings and compared with the existing methods. The results show that the proposed method can not only be effective in extracting fault characteristics and realize effective diagnosis of different bearing fault types and degrees, but also has better diagnostic effects than the compared methods.
  • SHEN Guohui,HAN Kanghui,LI Yipeng,JIANG Yonghan
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 226-233.
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    Wind tunnel test was employed to compare the wind pressure distribution and overall wind load of three-centered and bullet-type dry coal sheds. The distribution of shape coefficients of the two types of dry coal sheds under different wind direction was analyzed. Then the testing results were compared with those regulated in various specifications. The overall force coefficients on the two types of dry coal sheds under various wind azimuths were calculated and compared. The overall force coefficients of the middle part and both sides of the bullet-type dry coal shed were given. Studies show that the negative pressure on the windward side of the roof is relatively large when the wind direction is facing the wall, while the negative pressure on the middle and leeward sides is relatively small. The peak negative wind pressures of the two types of dry coal sheds appear near the top of sheds under inclined wind azimuth. When the wind direction is facing the side of the shed, the positive pressure regulated in the GB specification is less than the test values, and the negative pressure regulated in the AIJ and EN specification are greater than the test values. The shape coefficient changes sharply with the angle, therefore the expressions of segmented shape coefficient in the specifications are not reasonable. The fitting equation base on trigonometric function was thereby developed. The lift coefficients of the three-centered dry coal shed are smaller than those of the bullet-type shed with the same rise-span ratio, indicating that the overall averaged wind load of the three-centered shed is smaller than that of the bullet-type shed in the view of design.
  • ZHANG Lu1,2,LI Hua1,CUI Jie1,WANG Xiaodong1,XIAO Ling1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 234-250.
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    This paper presents a sparse index-based variational mode decomposition method to deal with the challenge of determining the decomposition mode number K when the number of composite signal sources is unknown. Based on the sparse prior theory of each component in the VMD decomposition, the adaptive optimal K value of VMD is discovered as the turning point of the sparse index from rising to falling. Considering the energy difference between different components, the energy weight factor is added in the computation of sparsity index. Finally, the sparsity index is determined as the average value of the marginal spectral sparsity of each component after decomposition. The results of simulations and real-world signal decomposition experiments prove the superiority of this method. Compared with the other two modified VMD methods, proposed method determines a more accurate K value and is more adaptive. Moreover, The results of experiment show that the method has a better decomposition effect than other signal decomposition methods like EMD. Proposed method introduces a novel concept for adaptive and efficient VMD decomposition of composite signals with unknown source numbers. To the next level, the robust noise experiment demonstrates that the suggested sparse index approach has a certain anti-noise ability. It shows that this method is relatively robust and it can be developed and applied to practical engineering.
  • SUN Yaru1,JI Jiadong2,HUA Zisen1,WANG Chengjun1,WANG Yan1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 251-258.
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    A hollow helical baffle (HHB) heat exchanger was put forward to balance the vibration performance and improve the heat transfer performance of helical heat transfer element. The fluid-solid coupling method was provided to study the effects of entrance velocity and the installed position of baffle on the performances of vibration and heat transfer. Based on the numerical results, HHB heat exchanger can effectively balance the vibration performance and improve the heat transfer performance. The vibration amplitude and heat transfer coefficient of heat transfer elements increase with the increase of entrance velocity. It is found that when the baffle is installed on the top side of the heat exchanger, the average vibration amplitude is the biggest, the average heat transfer coefficient is the smallest and the heat transfer uniformity is the best. The PEC value of HHB heat exchanger is always bigger than 1 which shows that the HHB heat exchanger has achieved the effect of enhancing heat transfer. When the baffle is installed on the bottom, top, left and right side of HHB heat exchanger, the PEC value of HHB heat exchanger can be increased by 2.04%, 7.87%, 1.32% and 0.03% compared with that of the conventional elastic tube bundle (CETB), respectively. When the baffle is installed on the top side of the HHB heat transfer, the PEC value is the maximum and the comprehensive heat transfer performance is the best.
  • LI Yuanbo1, WANG Jinxiang1, ZHAO Yaoyao2, TANG Kui1, WANG Hongfei1, CHEN Xingwang1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 259-265.
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    In order to comprehensively analyze the influence of configuration of explosively formed projectile (EFP) on its aerodynamic characteristics and penetration performance, the EFP design with good aerodynamic characteristics and penetration performance is realized. The forming and flight tests of EFP are carried out. On the basis of verifying the numerical validity, the forming process and aerodynamic characteristics of three typical configurations of back-ward-turned EFPs (solid rod, small cavity and large cavity) are analyzed based on ALE algorithm, and the numerical simulation of three configurations of EFPs penetrating semi-infinite thick steel are further carried out. The results show that the small cavity structure of EFP improves its flight stability; the increase of cavity reduces the storage capacity of EFP, and the average velocity decrease of the three types of small-caliber EFPs are 158m.s-1、172m.s-1、210m.s-1 at 1000 times the projectile diameter, respectively; with the increase of EFP cavity, the pit shape of the target plate will gradually change from funnel-shaped to equal-diameter shape. When designing EFP configuration from the perspective of engineering practice, solid type should be selected for short-range targets and small cavity type should be selected for long-range targets.
  • ZHAO Guochen1, XU Longjun1, ZHU Xingji2, XIE Lili1, 3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 266-274.
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    Since displacement parameters can describe the seismic performance of structures more scientifically and intuitively, the displacement-based seismic design method has become a research hotspot in the field of Earthquake Engineering. Displacement design spectrum is an essential approach for determining the seismic load in displacement-based seismic design methods. However, the current version of the Chinese seismic design code (after this referred to as the code) does not have relevant provisions on the displacement design spectrum. This paper proposes a displacement design spectrum method adapted to the code based on the characteristics of the actual displacement response spectrum of ground motions to facilitate the practical application. This method does not modify the code parameters but only adds two parameters: control period TD and peak ground displacement PGD, and the added parameters have a one-to-one correspondence with the relevant code parameters. In view of the fact that the force-based seismic design method still plays a dominant role in engineering practice, the proposed displacement design spectrum can be transformed into the acceleration design spectrum. To avoid the contradiction with the code, the proposed acceleration design spectrum is consistent with the code design spectrum when the period is less than 5Tg (site characteristic period). In the long periods, the proposed displacement design spectrum can reflect the main characteristics of the average displacement response spectrum of ground motions, and the proposed acceleration design spectrum is consistent with the average acceleration response spectrum. The research work can serve for the engineering application of the displacement-based seismic design method and guide revising the content about the design spectrum in the code.
  • CHENG Lu1,2,3, WANG Xueqing1,2,3, LIU Yan3, CHENG Xianyou4, XU Xin1,2,3, JI Yicai1,2,3, FANG Guangyou1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 275-281.
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    In order to accurately and efficiently identify nuclear electromagnetic pulse (NEMP) and lightning electromagnetic pulse (LEMP), a recognition and classification method based on adaptive signal decomposition and ensemble learning was proposed. First, for the problem of sample imbalance, data enhancement methods were used to preprocess the data set. In addition, Hilbert-Huang transform was applied to perform adaptive signal decomposition on NEMP and LEMP respectively. Then, features of the decomposed signal in the time domain, frequency domain and wavelet domain were extracted. Finally, the ensemble learning algorithm was used to identify and classify the extracted features. Experimental results show that the accuracy of the method on the measured data can reach more than 99.99%, and the false alarm rate of LEMP signals is less than one in ten thousand.
  • ZHANG Jian1, CHENG Xueli1, YUAN Pingping2, DUAN Minglei3, REN Weixin4
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 282-288.
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    In order to identify damage location and quantify damage degree, a structural damage detection method based on variational mode decomposition (VMD) and Chirplet transform was proposed. VMD was used to decompose structural vibration response signal to obtain modal components, and then Chirplet transform was applied for time-frequency analysis of the modal components. The energy index of modal component Chirplet transform was constructed for damage location identification, and the Chirplet transform time-frequency entropy was defined to quantify the degree of structural damage. The proposed method was verified by a numerical example of a simply supported beam with varied stiffness. The results show that the proposed method can accurately identify the damage location and quantify the damage degree of the structure regardless of single point damage or multi-point damage.
  • BAI Yu, YU Dianlong, ZHANG Zhenfang, CAI Li
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 289-295.
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    An engine acoustic liner model based on gradient acoustic hypersurface is proposed by designing a slit element array with variable length.Numerical simulation models and theoretical calculation models of the acoustic characteristics of the metasurface acoustic liner are established, noise reduction characteristics and mechanism are analyzed, and effects of changing the structural parameters and the spatial layout of the acoustic liner on the noise reduction characteristics are explored. Finally, the noise reduction effect of the metasurface acoustic liner is verified by experiments.The results show that the metasurface structure significantly expands the noise reduction frequency band of the acoustic liner to low frequency, and significantly expands its noise reduction frequency band. The analysis shows that the spatial layout of the acoustic liner also has a great influence on its noise reduction effect.
  • ZHANG Gaowang1,2, ZHANG Jiake1,2, YUAN Jie1,2, XU Wenyi1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 296-304.
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    To clarify the strain response of rubberized concrete pavement under impact loading, a testing method of strain response under impact loading was designed based on fiber Bragg grating strain sensor and heavy weight deflectometer (HWD). With this method, the differences in strain response between rubberized concrete pavement and ordinary concrete pavement under impact loading were compared and analyzed, and the effect of pavement size on the strain response of the pavement under impacting loading was investigated by monitoring different sizes of rubberized concrete pavement. The test results show that the addition of rubber particles changes the strain response distribution of concrete pavement under impact loading compared with ordinary concrete pavement, so that the horizontal strain in the concrete pavement decreases while the horizontal longitudinal strain at the edges and corners increases. Moreover, with the increase of the length of the pavement, the strains in the most unfavorable strain response directions of the rubberized concrete pavement at the center, edge and corner gradually increase, among which the longitudinal strain at the corner of pavement increases the fastest. In other word, the increase of pavement length will transfer the most unfavorable position and direction of rubberized concrete pavement from the transverse direction at the edge of pavement to the longitudinal direction at the corner of pavement. Therefore, the strain at the corner of the slab should also be considered in the design and construction of large size rubberized concrete pavement.
  • ZHAO Xiaofen1, WEN Zengping1, XIE Junju1, XIE Quancai2, XU Chao1, WANG Yuanjie3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 305-318.
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    Near-fault pulse-like ground motions cause severe damage in structures. Hence, for the probabilistic seismic hazard analysis and seismic design in the near-fault region, the pulse effects need to be taken into account. But, traditional ground-motion models may under-predict the velocity pulse-like strong ground motions in the near-fault region. Therefore, how to estimate the near-fault pulse-like strong ground motion is an active research topic in recent years. Here, based on the NGA-West2 database and the near-fault strong ground motions from the recent earthquakes, 316 pulse recordings are quantitatively identified by considering the uncertainty of pulse orientation and using the wavelet method. Then, based on the above data, quantitative empirical models of pulse amplification factor are proposed based on piecewise least-squares fitting of the results and compared with the previous pulse amplification model. Furthermore, the efficiency of the proposed model is tested. Compared with the previous pulse amplification model, the constant ordinate of plateau induced by pulse amplification of the proposed model is enhanced through considering the recent pulse ground motions. Finally, it is concluded that through multiplying the proposed model, the traditional ground-motion models can be corrected to reasonably approximate the pulse strong ground motions.
  • MAO Xiang1, YANG Deqing1,2, LI Qing1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 319-325.
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    Based on the barrel bending theory of rectangular thin plates, an equivalent beam element method is proposed for the calculation of bandgap properties of metamaterials that can be simplified in plane strain mechanical problem. The equivalent beam element method and the conventional equivalent plane strain method are applied to numerically calculate the bandgap characteristics of various typical configurations of negative Poisson's ratio metamaterials (re-entrant hexagonal, star-shaped, double arrowhead and rotating triangle), comparing the differences between the two methods in terms of bandgap calculation accuracy, calculation efficiency and applicability in topology optimization, and verified by experimental test results. It is shown that both the equivalent beam element method and the equivalent plane strain method have a high bandgap calculation accuracy, within 7% of the experimental measurements. The equivalent beam element method is about 50% more efficient than the equivalent plane strain method in bandgap calculation, but the scale of the topology optimization base structure model is larger and suitable for topology optimization of rod-like metamaterial structures. The equivalent plane strain method is less efficient in bandgap calculation and the size of the base structure model is smaller for topology optimization of continuum and skeleton metamaterials. This study can provide a reference for the design of bandgap topology optimization of metamaterials.
  • ZHAO Zhihong1,2, LI Chunxiu2, LI Lehao2, YANG Shaopu1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 326-333.
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    With the development of mechanical equipment fault diagnosis technology, people pay more and more attention to using deep learning technology to judge the type of equipment fault. At present, Transformer model based on attention mechanism has better feature extraction ability than Convolutional Neural Network, and has been successfully applied in the fields of natural language processing and computer vision. A Transformer method for mechanical equipment fault diagnosis (FD-Transformer) is proposed. Firstly, the original vibration signal is enhanced by dropout technology to improve the generalization ability of the model; Then the matrix form is obtained by multi-channel one-dimensional convolution; Then, the Encoder structure connected by Dense is used to extract the fault features of mechanical equipment. Finally, the fault diagnosis results are obtained by using the classification module. The experimental results show that the model achieves a fault recognition rate of more than 99% on both data sets. Compared with CNN, it can better extract the fault characteristics of mechanical equipment, and has certain engineering application value.
  • ZHOU Changwei, ZHANG Lijuan, ZHANG Chenlizi
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 334-340.
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    In flight, the tire burst of the retracted landing gear is caused by previous tire damage, which may occur anywhere on the exposed surface of the tire.In order to study the influence of tire blasting jet load on aircraft structure in the cabin, an engineering fitting method was adopted to reflect the instantaneous air field pressure distribution, and an engineering calculation model was established.Using this calculation model, the dynamic response process of typical large-size structures under instantaneous jet load was observed, and the structural damage was obtained. It was shown that the elastic deformation of the structure near the blasting point is very large, and the structure with the highest stiffness (such as edge strip) is the dangerous part;tire blasting in cabin causes more severe damage to structure;the computed results with the proposed model agree well with the test data,so the calculation model can correctly predict the pressure field distribution of jet load and the dynamic response process of the structure.This method can provide a reliable means for anti-tire blasting impact design and damage analysis of aviation structures.
  • LI Feifan, ZHAO Yanying
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(8): 341-350.
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    Considering the installation of MR damper on the aircraft landing gear and the time-delay issue in the process of shimmy, the time-delay semi-active control is used to achieve the purpose of amplitude reduction optimization. Firstly, in order to eliminate the influence of dimensionality and make the results better describe the objective universal law, after dimensionless treatment of the shimmy equations, the influence of dimensionless MR damper damping coefficient on the shimmy amplitude is analyzed. Then, in order to further reduce the amplitude, the design optimization criterion limits the anti-resonance amplitude in a small enough range. The time-delay semi-active control term is introduced into the shimmy equations, and a mathematical method for solving the characteristic equation of the time-delay dynamic equation is proposed. The anti-resonance amplitude can be controlled at a low level by using the time-delay semi-active control, and the second resonance can be almost eliminated. Lastly, it is verified and compared in the frequency domain and time domain, the correctness of the calculation and the superiority of time-delay semi-active control are proved.