28 February 2023, Volume 42 Issue 4
    

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  • GU Zi,FAN Yuan,YUAN Miaomiao,LU Wensheng
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 1-9.
    Abstract ( 359 ) Download PDF ( 191 )   Knowledge map   Save
    An asymmetrical friction damper (AFD) with asymmetrical elastic-plastic feature is studied to improve the tension-only braced frames under mainshock and aftershocks coupling strikes. Traditional tension-only braces (TOBs) have slackness problem which can result in severe structural performance degradation under the coupling of mainshock and aftershocks. Testing and analysis results revealed that the AFD is suitable to apply into tension-only braced frames, with asymmetrical elastic-plastic feature, providing large nonlinear restoring force with “self-tensioning” effect in static friction phase, and stable additional damping after sliding friction phase occurs. Theoretical models of static friction and sliding friction phase as well as the calculation method of additional damping ratio are proposed. Self-tensioning and damping protection modes based on AFD are developed. Comparison between nonlinear time history analysis on tension-only braced frame structures with TOBs and AFDs of two protection modes were conducted. The TOBs yielded under the design basis and rare mainshock, and caused structural failure due to their slackness under the rare mainshock and aftershocks, which verifies the risk of TOBs under mainshock and aftershocks coupling strikes. Two tension-only braced structures with protection modes of AFD can both improve the structure under mainshock and aftershocks coupling strikes, in which self-tensioning mode strengthens aseismic performance and damping protection mode prevents slackness, enhancing damping ability under mainshock and aftershocks.
  • YANG Pu1,FENG Liqiang2,HE Hanqin1,LI Feng1,LIU Liping1,NIU Changlin3,WEI Hongliang3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 10-18.
    Abstract ( 226 ) Download PDF ( 102 )   Knowledge map   Save
    In order to further expand the application of steel frame steel plate shear wall and concrete filled steel tubular column steel beam frame structure in high intensity area, two shaking table tests of 1/8 scaled model were carried out based on two high-rise (10-storey) residential buildings in Gansu Province. The results show that the infill wall reached yield state firstly, and then plastic hinge appeared on the outer frame. The plastic damage mainly occurred at the steel plate shear wall, the end of the adjacent beam and column base of the first floor, which reflects the concept of ' multi-defense levels of seismic engineering '. The natural frequency of the structure decreased by 19.5% and 17.4% in X and Y axis respectively after huge earthquake(1.20g); The damage of concrete-filled steel tubular column steel beam frame structure was mainly at the bottom, the fourth and the fifth floor beam ends, and a small amount of plastic hinge appeared at the bottom column base, reflects the design principle of ' strong joint-weak member '. The natural frequency of the structure decreased by about 19.5% and 17.8% in X and Y axis respectively after huge earthquake. Both types of structural systems can achieve the seismic fortification goal of ' no damage under frequent earthquake and no collapse under rare earthquake ', and have good seismic performance. In addition, the lateral deformation mode of the structural system is closely related to the stiffness distribution of the whole structure, and it becomes more obvious with the increase of the peak ground motion. The lateral stiffness of the steel frame-steel plate shear wall decreased along the height, and the whole structure exhibited lateral bending deformation mode. The lateral stiffness of the concrete filled steel tube column-steel beam frame (except the bottom) was uniformly distributed along the height, and the whole structure exhibited lateral shear deformation mode.
  • LUO Yinjian,LI Xiudi,CAI Tao,YANG Jinhong
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 19-27.
    Abstract ( 293 ) Download PDF ( 70 )   Knowledge map   Save
    Based on the isolated SHPB device, the engineered cementitious composite were tested for impact compression in the range of 4 strain rates from 14.8 to 16.3 s-1,31.8 to 36.5 s-1,57.8 to 65.5 s-1,167.3 to 200.2 s-1 to explore the dynamic mechanical characteristics and energy consumption mechanism of ECC at different strain rates.The test showed that The dynamic compressive strength and the dynamic peak strain of the ECC showed a significant strain rate enhancement effect, The increase of the dynamic compressive strength and peak strain of ECC at low strain rate, The effect of the enhancement at the high strain rate is not obvious; Fiber incorporation had similar effects on the stress strain curves of the ECC at different strain rates, The effect of fiber incorporation at the low strain rate on the ECC stress strain curve morphology was greater than on the high strain rate; The energy consumption capacity of the ECC is associated with the destructive morphology, When the energy consumption ratio exceeds 90%, The ECC with a fiber incorporation of 2.0% and 2.3% was 4 times more complete than that of the matrix material, It fully reflects the advantages of ECC in the field of anti-explosion reinforcement, It provides technical reference for ECC in the field of explosion resistance and impact resistance.
  • SHI Hao1,2,3,ZHANG Houquan2,SONG Lei2,LI Ming2,LI Mingjing1,LIN Gang4,SHI Xin1,LONG Wei1,WU Jiehao1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 28-38.
    Abstract ( 209 ) Download PDF ( 89 )   Knowledge map   Save
    The in-depth study on the dynamic characteristics of defective rock is of great significance to ensure the long-term stability of underground chambers such as deep coal mine roadway under strong disturbance actions like excavation blasting and main roof pressure. Based on the power-law distribution assumption of natural crack length, the Split Hopkinson Pressure Bar test system and the sandstone specimen model with different number of distributed pre-cracks are established by Particle Flow Code software. The effects of distributed pre-crack number on the strength and failure of sandstone specimens are studied. The results show that: (1) With the increase of the number of prefabricated cracks (NPC), the strength of the sandstone specimen decreases approximately linearly, while the decreasing law of the elastic modulus is closer to the cubic equation. Moreover, with the increase of NPC, the discreteness of the specimen strength and elastic modulus gradually increase, and the reduction process of the post-peak stress is also more complicated. (2) With the increase of NPC, the AE event curve of the specimen changed from the form of single peak and high extreme value to the form of multi-peak and low extreme value. (3) Under the action of impact load, the new cracks gradually distributed along the propagation direction of stress wave, and communicated and expanded from speckle form to lamellar form. And with the increase of NPC, the failure mode of the specimen changed from the surrounding failure mode to the weakening failure mode from left to right. (4) The specimens mainly fracture along the propagation direction of the stress wave, and the fewer NPCs, the larger the proportion of new cracks along the propagation direction of the stress wave.
  • TIAN Kaiwen1,QIU Ming1,2,WANG Dongfeng3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 39-47.
    Abstract ( 203 ) Download PDF ( 156 )   Knowledge map   Save
    The vibration of four-point contact ball bearing for power transmission mechanism was studied. A vibration analysis model of the four-point contact ball bearing considering lubrication was established. Taking QJ214 four-point contact ball bearing as an example, the vibration characteristics of the bearing under different structural parameters and working conditions were analyzed theoretically. The results showed that the smaller the radial clearance and the number of rolling elements of the four-point contact ball bearing, the smaller the bearing vibration; the curvature radius coefficient of the inner and outer ring grooves has a greater influence on the bearing vibration, and a reasonable choice of the inner and outer ring groove curvature radius coefficient can effectively reduce the bearing vibration; lubricant can alleviate vibration impact and reduce the vibration of the bearing; applying a reasonable axial load to the four-point contact ball bearing can reduce the vibration of the bearing.
  • QIN Jingjing1,2,3,ZHI Baoping1,2,3,YANG Chunjing1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 48-53.
    Abstract ( 165 ) Download PDF ( 91 )   Knowledge map   Save
    The stable operation of the unit plays an important role in supporting the economic and social development of the upstream and downstream of the hydropower plant. With the requirements for the stability of the hydropower plant, the vibration theory analysis and engineering practice based on prototype observations serious lag. Based on prototype observation, this paper considered the coupled vibration source propagation and amplification mechanism of the nonlinear structure, built a hybrid TPA model with the core of actual measurement and simulation calculation FRF, and carried out the research on the vibration transmission of the hydropower unit of the prototype-simulation simultaneous analysis. the unmeasured vibration sources of the hydropower unit were recognized, the contribution of the vibration component was determined, and the root cause of the vibration level on response target point is clarified. The result showed the local structural vibration reduction measures to form a set of hydropower plant vibration analysis and control based on the transmission path analysis method, which lay a theoretical foundation for the safe and stable operation, structural design and optimization of hydropower units.
  • GE Jinjin1,XU Ying1,2,CHENG Lin1,ZONG Qi1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 54-64.
    Abstract ( 237 ) Download PDF ( 185 )   Knowledge map   Save
    Rock blasting in tunneling showed that the rock failure in high in-situ stress environment was different from that in low in-situ stress condition or shallow rock mass. Especially, the propagation direction of main crack induced by blasting was greatly affected by the in-situ stresses. In this study, a transparent model similar material that conformed to the mechanical properties of hard rock is used to carry out the blasting similar model test under bidirectional load, to study the law of crack propagation in rock by blasting under initial in-situ stress. The experimental results show that the propagation of radial main cracks on specimens under initial static load is along the direction of maximum principal stress, which is different from that without in-situ stress; the propagation length and number of radial cracks decrease with the increase of lateral pressure coefficient; the Angle between propagation direction for the longest radial main crack and the direction of maximum principal stress increase with the increase of lateral pressure coefficient. Based on explosion mechanics, elasticity and stress wave theory, the relationship between initial in-situ stresses and propagation direction of main cracks induced by blasting in the rock is developed, that is, tan⁡φ=P_x/P_y (0< θ <45℃). It is verified that the angle between the propagation direction of main cracks and in-situ stress direction obtained by formula is basically consistent with that obtained from model test. This is of practical significance to understand the mechanism of rock fracture by blasting with high in-situ stresses.
  • LIU Hewei,LIU Kun,WANG Xiufei,WANG Zhengyao
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 65-70.
    Abstract ( 161 ) Download PDF ( 150 )   Knowledge map   Save
    Considering the effect of mesh size on hull collision failure simulation results, the tensile tests and simulations were carried out. The function between mesh size and failure strain was obtained through regression analysis. Based on this function, the RTCL failure criterion was modified and VUMAT subroutine was written. Finally, tensile tests and simulations under various stress states were carried out. Compared with the simulation results before and after modification, it can be seen that the modified method can effectively reduce the mesh size effect under different stress states, of which the effect is significant for medium and low stress triaxiality, and slightly worse for high stress triaxiality.
  • TIAN Wei,GAO Fangfang
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 70-80.
    Abstract ( 211 ) Download PDF ( )   Knowledge map   Save
    In order to improve the impact resistance of concrete after high temperature, multi walled carbon nanotubes (MWCNTs) with high strength, high toughness and good thermal conductivity are added into the concrete. And the fractal characteristics and energy consumption characteristics of carbon nanotube reinforced concrete under impact loading after high temperature are explored by the fractal index (i.e. fractal dimension), and the relationship between fractal dimension and dynamic compressive strength, energy consumption and impact toughness is established. The results show that after high temperature, the fractal dimension of concrete impact fracture increases with the increase of strain rate and temperature under impact load. At the constant temperature, the dynamic compressive strength, energy consumption and impact toughness of concrete increase with the increase of fractal dimension, while at the constant impact pressure, the they perform the opposite trend. Meanwhile, compared with ordinary plain concrete, concrete incorporating with multi walled carbon nanotubes owns light crushing degree, small fractal dimension, high energy consumption, impact toughness and dynamic compressive strength. In fact, the variation of fractal dimension essentially depends on the compactness of concrete and the propagation degree of internal crack. Well dispersed multi walled carbon nanotubes in concrete could not only refine pores, but also provide attachment points for hydration products and promote hydration process, so as to improve the compactness of concrete matrix. Besides, the bridging, pullout and thermal conductivity of multi walled carbon nanotube are also conducive to inhibit and delay the initiation and propagation of temperature cracks and load cracks. Consequently, the resistance of concrete with multi walled carbon nanotubes to high temperature and impact load has been effectively improved.
  • REN Li’na,CHEN Jintao,LI Jianhua
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 81-87.
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    Traditional state detection tends to cause the problem of over-detection. To solve this problem, a method to determine the interval of NC machine tool state detection based on real-time degradation is proposed. Describe the degradation process of CNC machine tools based on the Gamma process, and combine the risk of failures to give the state test interval in the early stage of the degradation process. The expected remaining life when the system state is at the defect threshold was given and used to constrain the state detection interval in the later stage of the degradation process. Thus, a two-stage non-equal period state detection interval decision model is established. Take the machining accuracy degradation process of the CNC machine tool spindle as an example to verify the proposed method, and then compare and analyze it with equal interval state detection and reliability-based state detection methods. The results show that the proposed method can greatly reduce the number of inspections, reduce maintenance costs, and avoid excessive inspections. The research results can provide a reference for the reasonable determination of the state detection interval.
  • WANG Ran1,YU Longjing1,YU Liang2,JIANG Weikang2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 88-94.
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    The accurate detection of cyclic frequency under strong noise interference is of great significance for cyclostationary signal processing. This paper proposes a new method of low-rank sparse decomposition technology based on Robust Principal Component Analysis (RPCA) applied to cyclic spectral density (CSD) matrix under low signal-to-noise ratio (SNR) to detect cyclic frequency. Firstly, RPCA is used to decompose the cyclic spectral density matrix into a low noise matrix representing noise interference and a sparse matrix representing cyclostationary characteristics. Subsequently, the sparse matrix is used to construct the detection function to realize the automatic detection of the cyclic frequency. The simulation results prove the superiority of the method in terms of detection probability under strong noise interference, and can provide the detection order for different signal-to-noise ratio conditions according to the receiver operating characteristic (ROC) curve of the detection of each order of cycle frequency harmonics. reference. In order to further verify the effectiveness of this method in application, this method is applied to the early fault diagnosis of rolling bearings. The analysis results on the accelerated fatigue life test data of rolling bearings prove that the method can accurately detect the characteristic frequency of the bearing fault from the low SNR vibration signal in the early stage of bearing failure, and realize the early fault diagnosis of the bearing.
  • JIANG Hui1,2,SONG Guangsong1,2,LIU Zhanshuo3,GUO Hui4,5,LU Wenliang1,ZHOU Yongzheng6,ZENG Cong1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 95-105.
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    A railway steel truss arch bridge with 400 m span in China was selected as engineering background.The method of low-frequency velocity pulse superimposed high-frequency original records was used to compound near-fault pulse ground motions.The dynamic time-history analysis was carried out and the response characteristics of the bridge and the transverse, longitudinal reduction technology were studied.Results show that, compared with earthquakes without pulse, the response of components increased obviously under near-fault pulse earthquakes.The sections of junction piers’ bottom, crossbeam, and approach piers’ bottom were damaged seriously.The bearings were also damaged seriously.Moreover, the beam and abutment were collided at some probability.The stress of the arch can be reduced by arranging the friction pendulum bearings in the whole bridge; however, the moment of piers cannot be controlled effectively, and the displacement of the beam end will be released.With the longitudinal seismic reduction scheme of “friction pendulum bearing + viscous damper”, the stress of the arch, the bending moment at the junction piers’ bottom and the displacement of the beam end can be decreased by 28.53%, 63.23%, and 22.52%, respectively.The seismic response of the crossbeam can be reduced greatly by adding buckling restrained brace in the transverse direction of the bridge.The bending moment of the junction piers’ lower and middle crossbeams can be decreased by 58.89% and 62.48%, respectively.The seismic performance of the bridge can be improved with the combined seismic reduction measures, and the requirements of seismic fortification can be met, which can be used as a reference for the seismic reduction design of the same type bridges.
  • SUN Haohan1,2,YUAN Si3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 106-115.
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    Adaptive finite element analysis of free vibration problems based on element energy projection (EEP) method has been proved to be reliable and efficient, where the errors of frequencies and modes are simultaneously controlled. In practical applications, the error evaluation of frequencies can sometimes be more required than the error distribution of modes. The paper proposes an approach to calculate the super-convergent frequencies, and then sets up the transformation relation between the global frequency error and the local mode error, so that the former is used to control the termination of the adaptive algorithm on the whole and the latter is used to drive mesh refinement locally. As a result, an adaptive finite element analysis of free vibration problem with frequency error control alone as the objective is established. The method is verified by its application to second order Sturm-Liouville problem and free vibration problem of elastic membrane.
  • BI Junwei1,2,3,GAO Guangyun1,4,GENG Jianlong1,4
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 116-125.
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    Deducing the 2.5D FEM governing equations for the transversely isotropic ground, and simplifying the CFG pile-supported subgrade by the equivalent pile walls, the 2.5D FEM model for CFG pile-supported transversely isotropic subgrade under high-speed train loading was established. Considering different train speeds, the effects of the stiffness ratio n of transversely isotropic ground on vibrations are analyzed. The vibration reduction mechanism of CFG pile composite subgrade is studied. Meanwhile, the influences of pile diameter, spacing, and area replacement ratio m on the vibration mitigation performance are discussed in detail. Results show that the ground vibrations induced by high-speed trains decrease with the increasing stiffness ratio n. Most of the dynamic load is undertaken by CFG pile composite subgrade, and transmitted along the depth into composite subgrade, which results in evidently reduction of ground vibrations. And the vibration mitigation effect enhances with the increasing diameter or the decreasing spacing. However, when the pile diameter or spacing exceeds one certain limit, further increasing diameter or shortening pile spacing cannot significantly improve the effect of vibration reduction. Additionally, with the increasing area replacement ratio m, the factor of vibration reduction FVR decreases gradually. When the area replacement ratio m is equal or greater than 0.06, further increasing area replacement ratio m has little effect on the vibration mitigation performance.
  • FENG Yulong1,2,WEN Hao1,CHONG Xun1,2,JIANG Qing1,2,ZHU Yi1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 126-136.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the ideas of buckling restraint and damage control, a steel frame joint with a buckling-restrained connector is proposed in this paper. A pair of core plates of the connector, for which a bucking-restrained system consisting of a restraining plate, two filling plates and an extending beam flange is set up, transmits flange axial forces and balance the beam end moment. Two specimens with and without the restraining plate were tested under low-cyclic loads, and the hysteresis curve, skeleton curve, energy dissipation and strain distribution were analyzed to investigate the influence of the restraining plate on the hysteresis performance of the joints; numerical simulations of the joints were conducted using the finite element software ABAQUS to study the influence of the core plate bolts and thicknesses on the hysteresis performance of the joints. The results show that the proposed joint can achieve the expected buckling restraint and damage control mechanism, i.e., the core plate first yields to dissipate energy, the restraining plate can prevent excessive out-of-plane buckling of the core plate, the main beam and column remain elastic, and the joint behaves a stable hysteresis performance and large deformation capacity. The bolt preload on the core plate determines whether the core plate will slip, which in turn affects the fullness of the hysteresis curve; the core plate thickness mainly affects the joint stiffness, bearing capacity and damage distribution. Finally, the formulae of bearing capacity, beam end displacement and skeleton curve of the joint were theoretically determined.
  • YU Tao1,SHUAI Zhijun1,WANG Xi1,JIAN Jie1,LI Wanyou1,JIANG Chenxing2,XIAO Qi3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 137-144.
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    In practical applications, when the system is operating at low flow rate, the pump-valve system is prone to instability along with severe structural vibration, which affects system reliability in serious cases. The unsteady excitations of the pump-valve coupling system in low flow rate are studied by using dynamic grid and sliding grid technology, and validated by experiments. Research shows that due to the periodic blockage of the guide vane area, low-frequency pressure pulsation appears. The movement and force of the valve disc are emphasized, and it showed that the pressure fluctuation of the outlet directly affects the fluid force on the valve disc, making it to flutter. The throttling effect at the hollow stem is the main cause of flow pulsation in the pump-valve coupling system. The above analysis shows that there is a strong coupling effect between the centrifugal pump and the spring check valve. This research can provide theoretical guidance for the design and optimization of the pump-valve coupling system.
  • WU Shaowei1,2,KE Lei1,HAN Guowen1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 145-155.
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    A meshfree weak-form method based on combining radial point interpolation method (RPIM) and modified Dirichlet-to-Neumann (MDtN) boundary condition is proposed for use in analyzing underwater acoustic radiation. In the method, unbounded problem domain is truncated by an artificial boundary to yield a finite computational domain. Simultaneously, MDtN boundary condition is imposed on the artificial boundary to guarantee the uniqueness of the solution, and RPIM is used to form acoustic shape function without use of mesh or connectivity of nodes for implementing field variable interpolations. The factors affecting the performance of the devised method are investigated. Numerical examples are performed to test the performance of the present method. The simulations indicate that this method can produce more accurate results together with faster convergency and better efficiency and is much less sensitive to the acoustic wave number compared to the finite element scheme. Therefore, this devised method is competitive for predicting underwater acoustic radiation.
  • YAN Shijun,PENG Yuhe,PENG Jian,REN Zhongjun
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 156-162.
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    A dynamic model is established of multi-body systems for hoisting under compound motion, and a control system combining input shaping and feedback control method is proposed for the system. The boom’s vibration and payload’s swing are described by using the spring-mass-damping system and suspension system respectively in the model. Based on Lagrange’s equation, a five-DOF space motion equation of the hoisting system is derived and given by using the recursive method. The combined input shaping method and the proportional-derivative feedback algorithm are used to suppress the payload’s swing and the boom’s elastic vibration simultaneously, according to the coupling vibration characteristics of the system. Results of vibration analysis show that the model can effectively analyze the dynamic characteristics of the multi-body system under the combining slewing and luffing motion excitation. Compared with the traditional input shaping control method, the vibration suppression effect of the designed controller is greatly improved.
  • TENG Wei1,GAO Lixin2,3,YUAN Xiaosa4,WANG Menglin1,XUE Pengbo1,WU Yanbing1,PAN Lei1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 163-170.
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    In order to study the failure behavior and mechanism of the laminates under high speed impact condition, the influence of fiber orientation on the high speed impact resistance of the laminate was explored by using air cannon high speed impact test, and the finite element model with effective error control was established. The model verified by optimization is used to calculate the impact test of the laminates with different variables. The experimental and simulation results show that the main damage modes of TC4/PEEK/Cf laminates under high speed impact are metal/composite interface delamination, internal lamination of composite, plastic deformation of metal and tearing and disconnecting of composite materials. By comparing the characteristics of high-speed impact failure of TC4/PEEK/Cf laminates with different fiber orientations, it is found that the high-speed impact resistance of TC4/PEEK/Cf laminates is related to the fiber placement angle. The impact energy dissipation performance of the laminates increases with the increase of the cross angle of the fibers, the ballistic limit and energy dissipation rate of fiber one-way laminates are the lowest, the ballistic limit and energy dissipation rate of 0°/90° fiber oriented laminates are the highest, and the impact resistance is the best.
    Key words: TC4/PEEK/Cf laminatest; nonlinear finite element numerical simulation;
  • YANG Yiqian1,LIU Penghui1,FANG Bin2,DONG Zhensheng1,ZHANG Hongliang3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 171-178.
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    Based on the measured data of the vibration source of 35 sections of the 24 urban rail transit underground lines. The excitation mechanism and frequency characteristics are discussed; the vibration data of the rail, track bed, and tunnel wall are used to identify the un-sprung mass of the vehicle and the P2 resonance frequency of the track coupling system , The stiffness of the fastener is deduced. The first natural frequency and Pined-Pined resonance frequency of the track system are analyzed based on the data of hammer impact test, and the stiffness of the fastener is deduced. It is proposed that the P2 resonance of the vehicle un-sprung mass and the track coupling system and wheel wear excitation frequency is one of the main excitation sources of urban rail transit environmental vibration and indoor secondary structure noise. The increase in stiffness of the fastener pad after aging increases the P2 resonance frequency. The contribution of noise is more significant than the contribution to environmental vibration. Pined-Pined resonance and wheel-rail roughness are the main excitation sources of urban rail transit environmental noise and interior noise.
  • YI Yali,ZHAO Teng,CHEN Meiyu,JIN Herong
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 179-184.
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    Aiming at the problems of large roller contact stress and large vibration noise of the system during the operation of the solid roller movable tooth, the roller movable tooth are improved, and a structural of the composite roller movable tooth is proposed. In the process of numerical simulation, the outer ring and inner core of composite roller movable tooth and solid roller movable tooth are flexible, and the rigid flexible coupling dynamic models of two different roller movable tooth are established respectively, The dynamic characteristics of the transmission system are analyzed. The simulation results show that compared with solid roller transmission, the peak value and fluctuation range of dynamic meshing force and vibration acceleration of composite roller movable tooth transmission are smaller, and the output is more stable. The flexibility of the composite roller increases the damping in the roller movable tooth transmission, reduces the impact load and improves the vibration of the system. The vibration test shows that the peak value of vibration acceleration measured by the composite roller movable tooth prototype is significantly reduced, and the vibration and noise of the overall transmission is significantly improved. The composite roller movable tooth structure plays a certain role in reducing vibration and noise in the transmission process.
  • AN Lei,WANG Wei,GONG Weiwei
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 185-193.
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    In order to study the influence of different lubricating media on the self-excited vibration of pneumatic hammer of aerostatic bearing, the single-degree-of-freedom vibration model of the bearing system was established by coupling the time-varying governing equation of the gas film flow field, the flow balance equation and the rotor force equation. The finite difference method was used to numerically solve the model, and the transient response curve of gas film vibration velocity was obtained to determine the stability of the bearing, and the reliability of the model and the validity of the program were verified through experiments. The calculation results show that the use of xenon can effectively reduce the occurrence of self-excited vibration of the pneumatic hammer; for the mixed gas of xenon and air, as the volume ratio of xenon increases, the attenuation trend of the gas film vibration velocity curve is strengthened, and the stability of the bearing is improved, the supporting force of the bearing is improved, and the higher the gas supply pressure, the greater the range of support force increases. When the xenon volume ratio increases from 0 to 0.6, the bearing supporting force increases rapidly, and the critical gas supply pressure also continues to increase. When the xenon volume ratio exceeds 0.6, the bearing support force and critical gas supply pressure increase slowly. Considering the cost, the xenon volume ratio of 0.6 can be used as the optimal volume ratio. This study provides a new idea for the suppression of self-excited vibration of pneumatic hammer of aerostatic bearing.
  • LIU Yuchi,JIANG Yufeng,WANG Shuqing,MA Chunke
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 194-203.
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    Deep-sea mining riser continuously suffer from internal Solid-liquid two-phase fluid abrasion and external wind-wave-current coupling load during operation, and structure damage gradually accumulates. Because of high slenderness ratio and flexibility, it is difficult to identify modal parameters, and the damage sensitivity of single measuring point response is low when applying traditional damage detection method to deep-sea mining riser. To solve the problems, a data fusion and one dimension residual convolutional auto-encoder (1D-RCAE) based method is proposed for deep-sea mining riser damage identification. Firstly, PCA is used to fuse bending strain responses from multiple measuring points into one variable. Then, the 1D-RCAE is used to extract the damage sensitive feature (DSF) from the fused variable. Lastly, the Mahalanobis distance between the extracted DSF under the currently testing and the baseline conditions is selected as the damage index. The damage detection effectiveness is verified on a 500m numerical model and a laboratory model of deep-sea mining riser, and the result shows that the accuracy of damage identification is higher than 98%. At the same time, the effects of noise pollution and changing marine environment is explored.
  • LI Fada1,SU Lei1,WAN Huaping2,LING Xianzhang1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 204-211.
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    In this study, uncertainty quantification of seismic response on pile-supported bridge structure in the permafrost region is carried out based on the finite element numerical model and seismic response characteristics of pile-supported bridge structure in the permafrost region. Firstly, the training samples of surrogate model for pile-supported bridge structure in the permafrost region are constructed using the experimental design method, which is used to generate maximum number of sampling points for uncertainty parameters. A Gaussian process surrogate model is used to simulate input-output relationship for physical processes of pile-supported bridge structure in the permafrost region, and then a reduced order surrogate model is used to perform uncertainty quantification. Seismic response uncertainty of pile-supported bridge structure in the permafrost region is assessed based on statistical variables and variational parameters. The study results showed that: (1) As coefficient of variation (COV) increases from 5% to 30%, time history response of bridge structure the consequent increase correspondingly. The parameter uncertainty of bridge structure has a significant effect on seismic response of pile-supported bridge structure in the permafrost region. (2) As the COV of input parameters for bridge structure are increased, the corresponding COV of seismic response is also increased. This indicated that the COV increase of input parameters for bridge structure directly affects the COV of seismic response. The uncertainty quantification analysis of pile-supported bridge structure in the permafrost region described in this study can provide analytical methods and ideas for the simulation of similar structure.
  • DU Yimei1,HU Bo1,2,3,LI Mingjie1,SHI Shengguo1,2,3,SHI Jie1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 212-218.
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    Periodic structure has great application potential in vibration and noise reduction, filtering, etc. Functionally graded materials (FGMs) are novel composite materials with excellent properties in recent years. This paper combines periodic structure with functionally graded materials, and proposes a quasi-periodic structure with gradient changes of thickness and impedance to meet the requirements of underwater low-frequency broadband applications. Firstly, the reflection coefficient of the quasi-periodic structure with gradient change of thickness and impedance is simulated using the transfer matrix method. The band gap characteristics of the quasi-periodic structure and the periodic structure are compared, and the influence of thickness and impedance on the band gap of the quasi-periodic structure is analyzed. Finally, experimental samples were prepared and underwater verification experiments were carried out. The results show that the first band gap of the quasi-periodic structure with gradient change of thickness and impedance has a lower starting frequency and a higher cutoff frequency. The impedance gradient change has greater effect than the thickness gradient change on the band gap characteristics of the quasi-periodic structure. These results can provide reference for quasi-periodic structure application on vibration and noise reduction of underwater low-frequency broadband.
  • LI Nailu,FAN Ruijie,LUO Ziwei,CAO Zhiguang
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 219-228.
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    The actuator and closed-loop loop of aeroelastic control system will have time delay in practice. Due to the aeroelastic sensitivity and the environmental complexity, the delayed control signal is easy to lead to the rapid deterioration and even instability of aeroelastic control system. However, this problem is rarely considered in previous studies. To solve the problem of delayed aeroelastic control of the airfoil,an optimal aeroelastic control technique is designed based on bidirectional random grey wolf optimization (BRGWO) algorithm and modified filtered Smith predictor. First, an aeroelastic controller is proposed using improved the Smith predictor based on a second order filter. Then, a novel bidirectional random grey wolf optimization (BRGWO) algorithm is designed to improve the global search of optimal controller parameters under time delay. The BRGWO algorithm is proposed to improve the preying strategy of the wolf in different level, so as to increase the change of leaving non-optimum zone and avoid the local optimum. The stability of the closed-loop system is proved theoretically by small gain theorem. The simulation results show that proposed controller performs better on delayed control compensation and aeroelastic control performance, compared to conventional intelligent optimization algorithm (genetic algorithm, grey wolf optimization) and published methods (classical Smith predictor,PI-PD Smith predictor, traditional filtered Smith predictor). The satisfied delayed control performance of aeroelastic system is maintained with strong rubustness on various cases, such as uncertain time delay, uncertain wind velocity, varying stiffness and load disturbance.
  • ZHI Baoping1,2,3,QIN Jingjing1,2,3,YANG Chunjing1,2,3,YU Yang3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 229-235.
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    According to the Complex vibration element of hydropower unit, EEMD-SOBI method, namely, Ensemble Empirical Mode Decomposition-Second order blind source separation, is proposed to identify multisource vibration signals. The vibration source components are recognized by the primary decorrelation of the observation signals, the whitening calculation of the second-order statistics of each signal, then the compute of the diagonalization matrix, and the optimal estimation of the vibration source. the results show that the observation signals are used to decompose and identify basically the source information with insensitivity to noise. The existing problems for directly application of SOBI are the frequency diffusion, the non-full rank of coefficient matrix, the decorrelation preprocessing of observation signals and so on. The above problems are well resolved recently, so SOBI can be exploited for vibration source analysis of hydropower unit vibration testing.
  • HONG Guang1,2,LI Jiawu1,WANG Jiaying1,WANG Feng1,WANG Jun1,LI Yu1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 236-246.
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    The paper researches the flutter performance of suspended double-deck flat box girder using the wind tunnel and numerical Simulation. The flutter performance of the suspended double-deck flat box girder is analyzed through modal decomposition, section pressure distribution and flow field modal. The research indicates that under the aerodynamic interference from upper section, the generation、migration and shedding of large-scale vortices at the lower edge of the lower section cause that the lower section occurs the bending-torsional coupling "soft flutter". Moreover, due to the structural static coupling between the upper section and the lower section, the bending-torsional soft flutter at the lower section induces the bending-torsional soft flutter of the double-deck flat box girder.
  • YANG Weiguo1, GE Jiaqi2, LI Binbin1, WANG Meng1, LIU Pei1, ZOU Xiaoguang1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 247-255.
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    In order to obtain the true characteristics of ground motions acting on cultural relics, a soil-museum-showcase-cultural relics system model and a rigid foundation (museum-showcase-cultural relics) system model were established. Three seismic wave amplitude modulations were selected for time-history analysis. The analysis of parameters such as, displacement, and cultural relic angle considers the influence of soil-structure interaction (SSI). Taking the Class II site as an example, the analysis and consideration of the law of vibration transmission from soil to cultural relics under the soil-structure interaction provides more accurate data support for judging the safety of cultural relics under earthquake. The results show that for the structure, considering SSI makes the calculated seismic response smaller. For showcases and cultural relics, considering SSI under small earthquakes makes the calculated seismic response smaller. However, under the action of moderate and large earthquakes, the response of display cabinets and cultural relics when considering the SSI effect is often greater than that of rigid foundations. Based on the perspective of protecting cultural relics, the impact of SSI should be considered in earthquake analysis, especially large earthquake analysis. For the Class II site and the 4-story reinforced concrete frame structure, considering the influence of SSI, in the process of seismic wave transmission from the soil to the cultural relic, the structure enters plasticity under the earthquake, and the maximum dynamic amplification factor of the cultural relic is 5.70 (including soil, Structure, power amplification factor of the showcase), the maximum sliding amount is 129.69mm, and the phenomenon of overturning occurs. The spectrum components of each transmission link have certain differences. The structure, display cabinets and cultural relics will all have an impact on the seismic wave spectrum. The impact of each part should be taken into account in the analysis.
  • PENG Wenlin1,YU Jianda1,2, HU Lei1, SUN Hongxin1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 256-262.
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    With the increasing span of the footbridge, the pedestrian quality has a greater impact on the natural frequency of the footbridge, in order to improve the effect of broadband frequency vibration reduction for footbridge, A new vibration reduction approach called damping cable is proposed, which composed of a damper and a return spring in parallel and then connected in series with the cable. Firstly, the footbridge is simplified as a simply supported beam, the bending vibration equation of footbridge with damping cable is established, and the calculation formula of the additional damping ratio provided by the damping cable for the pedestrian bridge is obtained by analytical method. Then, through the model experiment, the variation laws of the additional damping ratio provided by the damping cable for the bridge is analyzed when the parameters such as the frequency of the footbridge and the damping coefficient are changed. The results show that the damping cable can provide a very large additional damping ratio for the footbridge, and the theoretical calculation formula of the additional damping ratio is consistent with the experimental results. Finally, based on the theoretical formula of additional damping ratio, the influence of damping cable parameters on the vibration mitigation of footbridge is analyzed.
  • SHU Shuai, TANG Baoping, HUANG Yi, ZHAO Chunhua, FU Hao
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 263-269.
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    Aiming at the problem of high transmission energy consumption when each data packet is transmitted in Acknowledgement mode when the mechanical vibration wireless sensor network transmits a large amount of data, Adaptive Transmission Control Method of Large-scale Data is proposed. First, using the grouped data packet detection mechanism to reduce the additional energy consumption caused by the transmission of acknowledgement frames, the determining optimal number of packets through experiments to avoid wasting the limited storage resources of Wireless Sensor Networks nodes; Secondly, using the specific flag bit of the frame control domain to inform the sending node of the packet loss status without additional data frames, which avoid feedback information packet delivery conflicts, then optimizing the feedback information packet back-off index to reduce the listening energy consumption caused by the delay of feedback information packet delivery; Finally, fitting the relationship between packet loss rate and link quality indicator by least square method for node’s adaptively selection of the best transmission mode. The experimental results show that the proposed method can effectively reduce the energy consumption of data transmission and increase the transmission rate.
  • LIU Yong1,2, GUO Xinhui1,2, WEI Jianping1,2, ZHANG Hongtu1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 270-278.
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    In order to solve the problems of rapid wear of drilling tools and low drilling efficiency in the process of deep rock excavation, based on the particle impact rock breaking technology, a method of using high-pressure gas to accelerate the impact of rock bullets on the pre-cracked rock mass of the advancing face was proposed to reduce the wear of drilling tools. The SHPB experiment and the three-dimensional scanning experiment were used to test the absorbed energy of rock failure and the newly added surface area, and a theoretical model for calculating the absorbed energy of rock impact failure was constructed. At the same time, a self-developed rock bullet impact rock breaking experimental device was used to study the influence of gas pressure, bullet mass and lithology on the rock breaking. The results show that the specific surface free energy "γ" _"s"  of the experimental granite rock sample was 6.34 mJ/mm2, based on the measured rock fragmentation absorbed energy and added surface area. Increasing the gas pressure can effectively increase the impact kinetic energy of rock bullets, the absorbed energy of granite and the new surface area. At the same time, the crushing and ejection energy of rock bullets will increase, and the efficiency of the impact kinetic energy of rock bullets into granite crushing will be reduced. The absorbed energy is a power product of the mass and kinetic energy of the rock bullets. Keeping the air pressure constant and increasing the mass of the rock bullets can increase the kinetic energy and absorbed energy conversion efficiency of the rock bullets within a certain range, and enhance the damaging effect. Too much increase in rock mass will result in a decrease in kinetic energy, thereby reducing the conversion efficiency of absorbed energy. The specific surface free energy of rocks with different lithology is different. However, the effects of gas pressure and mass of rock bullets on the impact failure effect of rocks with different lithology are basically the same. The research conclusions of this paper will provide theoretical and technical support for hard rock auxiliary excavation.
  • MA Chao1,2, LIU Lei1,2, YANG Hongjie1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 279-285.
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    The ground test with microgravity simulation is one of the important measures to verify whether the vibration isolator can work reliably in orbit. When the suspension method is usually used for microgravity simulation, the vibration of the suspension spring at the local mode is easy to be introduced into the vibration isolation platform. With the problem, firstly, the modal damping of spring is improved by the parallel connection of PVC tape and suspension spring. Then the continuous dynamic model is established for the tape suspension spring of the microgravity simulator, and the effects are compared for the modal vibration of pure suspension spring and tape suspension spring on vibration isolation platform. Finally, the ground experimental system is built, and the accuracy of the dynamic model of the suspension spring is verified through experiments. The experimental results show that pasting PVC tape can increase the damping of the suspension spring and reduce the modal vibration of the spring below 1ug, so as to reduce the impact of modal vibration on passive vibration isolation and effectively alleviate the limitation of modal vibration on the control performance of the active vibration isolation controller. As a result, the state with microgravity simulation can more accurately reflect the working state in orbit.
  • WANG Fengjiao1, LI Mingqiang1, PENG Haifeng1, LU Yang2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 286-294.
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    Based on the stopband characteristics of periodic structure as well as the shear performance of rubber material, a new radial periodic strut for main gearbox was proposed to suppress the transmission of high frequency vibration from the main gearbox to the fuselage, which is able to realize the noise reduction in helicopter cabin. For this configuration, the equivalent stiffness and mass of the radial sub-element were derived using the axially symmetric element, Hooke's law and virtual displacement principle, and the dynamic and static analysis models of the whole strut were further derived. On this basis, the influence of the main design parameters of the radial periodic strut on the stopband characteristics and the strength and stiffness characteristics is obtained through the parameter analysis. Subsequently, a sample strut was designed to meet the requirements of a certain helicopter model. Simulation analysis was then carried out from three aspects of vibration reduction characteristics, stiffness and strength to verify the feasibility and effectiveness of the proposed scheme in the application of helicopter. The results show that the broadband noise attenuation is obvious and up to 40dB in the frequency range of 500-4000Hz.
  • WANG Xing1, ZHANG Han1, ZHU Jiazheng1, LIN Jianbo1, DU Zhaohui2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 295-305.
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    Due to the high running speed, large variation of operating conditions, complex structure and large interference noise, the weak fault features often exist in multiple subspaces. At present, the data-driven diagnosis model is not enough to reliably capture rich feature information in different subspaces. In order to solve the above problems, MADM(A Multi-head Attention Diagnosis Method Based on Signal Features) is proposed to identify and diagnose the fault state of aeronautical bearings under high-speed and non-stationary working conditions. In this method, the features of the original vibration signals are extracted by convolution module and bi-directional GRU module, and then the multi-head attention module is introduced to make the network pay attention to and fuse the information of different representation subspaces at the same time to improve the significance level of fault features. Finally, the full connection module and Softmax classifier are used to diagnose the high-speed bearing fault. The experimental results show that the proposed MADM diagnosis method can realize high precision and reliable diagnosis of aeronautical bearings with rotational speed of more than 12000 rpm and the minimum spalling area of 0.5 mm2, and is better than the current mainstream depth diagnosis methods.
  • WANG Xiaoqing1, YANG Tianyang1, ZHANG Yibei1, GAO Jifeng1, CHEN Wujun1,FANG Guangqiang2, XIE Chao2, CAO Zhengli2, MA Jia2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 306-311.
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    Shape memory composite (SMPC) is an intelligent material with promising applications in the aerospace field. The modal tests were conducted on a five-bay SMPC deployable truss array antenna after repeated folding and unfolding shape memory process, and the natural frequencies and mode shapes are obtained through modal parameter identification to investigate the influence of prestressed cable and array panel on structural dynamics. The results show that the prestressed cable can improve the overall stiffness and shear resistance of the truss antenna along the longitudinal direction, and the array panel can improve the torsional stiffness of the truss. An acoustic-structure interaction (ASI) finite element model which include the effect of air on the array surface is established for the computational modal analysis, and the results are in good agreement with the modal test, indicating the accuracy of the simulation analysis method.
  • YANG Yanhong1, WU Hao1, FANG Qin2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 312-324.
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    The impact of commercial aircraft became a beyond design basis accident that must be considered for the nuclear power plant after 9/11 incident. Aiming to explore a reasonable and reliable numerical simulation method to accurately evaluate the damage and vibration responses of nuclear power plant under impact of commercial aircraft, firstly, the 1:15 scaled model test of aircraft impacting the nuclear power plant was simulated. The accuracy of the adopted material model and parameters as well as the numerical simulation method was verified by comparing with the damage of the plant structures and the acceleration-time histories of the plant at different elevations in the test. The refined finite element models of the prototype AP1000 nuclear power plant was further developed, the numerical simulation of A320 aircraft at 100m/s impacting the AP1000 reactor building at the crane girder elevation was performed, and the damage of the plant and the vibration responses of the crane girder were evaluated. The results showed that, in the present scenario, the impact of commercial aircraft on the reactor building will lead to the perforation in the fuselage impact region, while the internal steel containment vessel can maintain its overall tightness; the vibrations of crane girder are below the limit, the crane will not drop, the safety of reactor is guaranteed.
  • LU Zhirong1, WANG Xiaoming1, ZHOU Wenya2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(4): 325-332.
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    Shape of reflector antenna can be actively adjusted to improve shape accuracy and signal transmissibility by smart piezoelectric actuator. Conventional static shape control strategy only can evaluate the value of terminal voltage, but transient dynamic response and residual vibration are easily excited during voltage loading process. It is difficult to achieve high accurate dynamic shape control effect by the static control strategy, even it would affect the stability of system. To this end, the parabolic reflector actuated by macro fiber composites (MFC) is used as the object for investigating the finite-time dynamic shape control algorithm. First, the dynamic equations are derived based on the finite element method, and the control problem is transformed into the finite time time-varying LQ terminal control and tracking control problem, and then the feedforward and feedback time-varying control law is obtained by solving the differential Riccati equations (DREs). The results show that the proposed finite time dynamic shape control algorithm can realize continuous and smooth dynamic surface adjustment effect of the active reflector with the avoidance of the excitation of incidental vibrations during voltage loading process, and effectively improve the static and dynamic control performance of the active reflector.