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2024 Vol. 43, No. 7 Published: 2024-04-15 1 Influences of aerodynamic interference effect on VIV performance of large-span asymmetrical twin parallel decks SONG Yubing, TI Zilong, YANG Ling, LI Yongle, LI Zeteng During the construction of twin decks, the long-span asymmetrical twin parallel decks represent a unique design, where both the highway and railway are arranged side by side at the same elevation. Due to the disparate dynamic characteristics of the highway bridge and the railway bridge, the considerable variation in wake characteristics of the decks, as well as the pronounced and consequential aerodynamic interference between the asymmetrical twin decks, the vortex-induced vibration (VIV) characteristics of the asymmetric twin decks become considerably more intricate. To comprehensively investigate the impact of interference effects on the VIV behavior of decks, a series of wind tunnel tests and fluid-structure interaction numerical simulations were conducted on twin decks. These experiments and simulations were conducted in the context of a long-span asymmetrical twin separated parallel deck configuration, where the highway deck was designed as a Π-type superimposed deck and the railway deck was a streamlined box deck. The research findings indicate the following: (1) The Π-type highway deck exhibited significant vertical bending and torsional vibrations when exposed to the windward side, showing typical VIV "lock-in" characteristics between the wind speed range and the structural vibration frequencies. However, these vibrations diminished when the deck was on the leeward side. (2) The streamlined railway deck showed no significant vibrations when positioned on the windward side, but substantial vibrations were observed on the leeward side, with amplitudes rapidly rising and falling, without a distinct "lock-in" range. (3) The numerical flow field indicates that the scale and distribution of vortical structures near the deck vary significantly when the highway is located at different positions (windward and leeward sides). The presence of large-scale vortices in the cavity below the bridge deck and the periodic variation of vortical structures are the main reasons for vortex-induced vibration on the windward side. On the leeward side, influenced by the disturbance effect, the scale of vortices in the cavity below the bridge deck decreases, the oscillation frequency of lift changes, and the phenomenon of vortex-induced vibration lock-in disappears. (4) Flow fields and pressure distributions near the railway revealed stable flow patterns when positioned on the windward side, with self-excited lift forces approximating steady forces. However, when positioned on the leeward side, the railway surface experienced a larger negative pressure area due to the interference of the highway wake, leading to significant vibrations caused by the pulsation of the highway wake and resulting in oscillations of the railway's aerodynamic lift. This study systematically investigated the aerodynamic interference effects between asymmetrical twin parallel main girders and their impact on VIV performance. The underlying VIV and aerodynamic interference mechanisms were revealed, providing valuable insights for the engineering design of similar bridges. 2024 Vol. 43 (7): 1-9 [Abstract] ( 316 ) HTML (1 KB)  PDF (5011 KB)  ( 147 ) 10 Application of 2-D acoustic black hole in piezoelectric vibration energy collection CHEN Bing, ZHANG Yangkun, REN Jiang, YIN Zhongjun The Acoustic Black Hole (ABH) effect can generate strong energy concentration, which can convert low-quality vibration energy of high frequency and low amplitude into high-quality vibration energy of high amplitude, so as to facilitate utilization. A piezoelectric energy harvesting device for a circular two-dimensional acoustic black hole is proposed. The finite element analysis results show that the annular two-dimensional ABH structure can significantly improve the energy collection efficiency in the wide band domain. The experimental test platform of circular two-dimensional acoustic black hole piezoelectric energy collector is built, and the correctness of the simulation results is verified by experiments. Compared with the classical two-dimensional ABH structure, the annular two-dimensional ABH structure has better energy collection efficiency and structural strength. The influence of the geometric size of the piezoelectric plate on the energy collection efficiency of the device was analyzed, and the geometric size range of the higher output power was obtained. The orthogonal test design was carried out to study the comprehensive influence of the truncation thickness, the size of the piezoelectric plate, the diameter of the central platform, the power exponent, and other factors. 2024 Vol. 43 (7): 10-17 [Abstract] ( 137 ) HTML (1 KB)  PDF (2595 KB)  ( 113 ) 18 Intelligent identification of bridge modal parameters based on sliding-window OPTICS algorithm and DATA-SSI algorithm CHEN Yonggao1, ZHONG Zhenyu1,2, LUO Xiaofeng1,2 In order to better identify the modal parameters of existing bridge structures. Moreover, in view of the shortcomings of the existing Data-driven Stochastic Subspace Identification(DATA SSI algorithm), which is unable to achieve automatic screening of true and false modes in the stability diagram. A new intelligent identification algorithm of modal parameters is proposed. Firstly, the sliding window technology is adopted to achieved the division of input signals, so as to avoid the false modes and modal omission as much as possible. Secondly, the Ordering Points To Identify the Clustering Structure (OPTICS) algorithm is used to fulfill the intelligent screening of the real modes in the stability diagram. Finally, the proposed algorithm is applied to a real large cable-stayed bridge for identifying the frequency and mode shapes of the main beam. The results show that the errors among the frequency value which is identified by the improved algorithm, the theoretical value (It means MIDAS finite element results) and the actual value (field dynamic characteristic measurement result) are within 5% separately, and the identified mode shape diagram has a high similarity with the theoretical mode shape diagram. 2024 Vol. 43 (7): 18-29 [Abstract] ( 92 ) HTML (1 KB)  PDF (4367 KB)  ( 99 ) 30 Joint selection of horizontal and vertical ground motions based on generalized conditional intensity parameters WANG Xiaolei1, WANG Ximing1, YAN Weidong1, L Dagang2 In order to reasonably consider the vertical earthquake effects and realize the joint selection of horizontal and vertical ground motions, this paper proposes a joint selection method of horizontal and vertical ground motions based on generalized conditional intensity measure (GCIM). The basic theory of GCIM is extended, the construction method of GCIM distribution for horizontal and vertical ground motions is proposed, and compared with the "unconditional distribution", the theoretical details of the joint selection method of horizontal and vertical ground motions based on GCIM are proposed, the actual calculation example with horizontal IM as the condition is given, and the existing horizontal-horizontal, horizontal-Vertical IM correlation coefficient models are used to construct horizontal and vertical ground motion GCIM target distributions, and joint selection is carried out according to the target ground motion database, and the selection results are compared with the traditional selection method to illustrate the rationality of the method. The results show that there are some differences between the constructed horizontal and vertical GCIM distributions and the "unconditional" distribution; the joint selection results of horizontal and vertical ground motion match well with the target theoretical distribution; compared with the selection method considering only the horizontal GCIM ground motion, the joint selection method can take into account the vertical ground motion characteristics well, and will not affect the horizontal direction. The combined horizontal and vertical ground motion selection method proposed in this paper can consider the horizontal and vertical ground motion characteristics more reasonably and comprehensively, and provide the ground motion input basis for the research of seismic performance of engineering structures under the action of horizontal and vertical ground motion. 2024 Vol. 43 (7): 30-41 [Abstract] ( 98 ) HTML (1 KB)  PDF (6443 KB)  ( 53 ) 42 Effects of blasting excavation of 1st tunnel of small clear distance tunnels on surrounding rock stability of 2nd tunnel LI Xuzhe1, LI Wenjie1, BI Zhigang2, LIANG Bin1 In order to study the influence of blasting excavation on the stability of surrounding rock in the tunnel with a small clear distance, taking the Yidong high-speed Fangjun tunnel project in Zhejiang province as the engineering background, the calculation formula of surrounding rock vibration velocity during blasting construction was derived according to the law of energy attenuation. The finite element software MIDAS GTS NX was used to simulate the change law of surrounding rock vibration velocity and stress under different clear distance conditions. The numerical results of vibration velocity in surrounding rock are compared with the theoretical values to verify the accuracy of the formula. According to the relation between vibration velocity and stress, the threshold value of vibration velocity is proposed to ensure the safe construction of tunnels. The results show that: (1) The maximum relative error between the theoretical value and the simulated value is 5.9%, and the maximum relative error between the theoretical value and the field monitoring data is 7 %, which verifies the accuracy of the theoretical formula. (2) There is a negative correlation between the peak vibration velocity of the rear tunnel and the distance between the blasting center of the first tunnel, and the peak vibration velocity of the monitoring point on the blasting side of the surrounding rock is greater than that on the back explosion side. 2D is the minimum safe clear distance of the anti-military tunnel during blasting construction (D is the clear distance of the tunnel), at this time, the maximum peak vibration velocity of the excavation of the upper step is about 1.20 times that of the lower step. (3) After blasting excavation, the peak stress and vibration velocity of the surrounding rock are mainly concentrated near the arch waist and arch foot. With the increase in the clear distance, the influence of the advance tunnel on the rear tunnel gradually weakens and is eventually ignored. (4) Under the action of blasting, there is a certain linear relationship between the peak stress of surrounding rock and the peak vibration velocity, and the vibration velocity control threshold to ensure the safe construction of tunnel blasting is 1.9 cm∙s-1. The research results can provide a reference for the blasting construction of similar small clear-distance tunnel projects in the future. 2024 Vol. 43 (7): 42-49 [Abstract] ( 153 ) HTML (1 KB)  PDF (3881 KB)  ( 49 ) 50 Effects of structural parameters of throttling groove on valve opening pressure impact and cavitation characteristics CHEN Yuanling, OUYANG Chongqin, PENG Zhuo, CHEN Chengzong, SHI Hao, WANG Mengqiao The structure of the throttle groove of the spool of the hydraulic control valve has a strong impact on the dynamic characteristics of the valve, and a poor throttle groove structure will lead to a great hydraulic valve opening instant pressure shock. For a model of load-sensitive multi-way valve in the application of sugarcane combine harvester whistling and hydraulic shock, combined with dynamic mesh and RNG-K-ε turbulence model to compare the pressure shock and cavitation of U + T throttle groove and V throttle groove. It was found that the pressure shock of the spool with V-groove decreased by 19.37% and the maximum cavitation decreased by 43.7% compared with that of the spool with U+T-groove under the same condition. The V-groove was selected for further study, and the peak pressure under different throttle groove structural parameters was obtained through orthogonal tests. The BP neural network is used to establish an agent model of the structural parameters of the V-throttle groove and the pressure impact, and the optimal configuration of the structural parameters of the throttle groove is obtained by combining with the Gray Wolf Algorithm (GWO). According to the optimization results of the production of valve spool and test, the results showed that the inhibition of pressure shock effect was significant, the system pressure overshooting down to the original 52.4%. 2024 Vol. 43 (7): 50-56 [Abstract] ( 76 ) HTML (1 KB)  PDF (2872 KB)  ( 65 ) 57 Effects of circumferential intake distortion on aeroelastic stability of labyrinth seal ring SU Guozheng1,2, SUN Dan1,2, WANG Zhi1,2, LI Yu1,2, WANG Wen3, XU Meipeng3 Aiming at the aeroelastic stability of the labyrinth seal ring of aero-engine under circumferential intake distortion, a solution model for the aeroelastic stability of the labyrinth seal ring based on the energy method was established by using three-dimensional interpolation and unsteady dynamic grid technology. On the basis of verifying the accuracy of the solution model, the influence law of symmetric intake distortion, asymmetric intake distortion and intake distortion degree on the aeroelastic stability of the labyrinth seal ring was studied, and the distribution characteristics of aerodynamic work in different regions of the tooth cavity were analyzed. The influence mechanism of circumferential intake distortion on the aeroelastic stability of labyrinth seal ring was revealed. The results show that the circumferential intake distortion can change the aerodynamic damping ratio and has a great influence on the aeroelastic stability of the labyrinth seal ring. In the case of asymmetric intake, the aeroelastic stability of labyrinth seal ring decreases first, then increases and then decreases with the increase of distortion degree. For symmetric intake, the aeroelastic stability of labyrinth seal ring first increases and then decreases with the increase of distortion degree. Compared with the asymmetric intake distortion, the aeroelastic stability of labyrinth seal ring is less affected. In the case of aeroelastic instability, the region with the greatest influence of circumferential intake distortion on aerodynamic work of the labyrinth seal ring of the first tooth is located in the windward region of the first labyrinth seal. It is the region with the worst circumferential pressure uniformity of the flow field. The influence of circumferential intake distortion decreases with the increase of relative distance. The total aerodynamic work at the bottom of the labyrinth seal ring is greatly affected by circumferential air intake distortion. The size and shape of the bottom cavity can be changed during the structural design to reduce the influence of circumferential air intake distortion on the aeroelastic stability of the labyrinth seal ring. 2024 Vol. 43 (7): 57-66 [Abstract] ( 75 ) HTML (1 KB)  PDF (3988 KB)  ( 14 ) 67 Analysis of dynamic impact coefficients and affecting factors of stay cables in cable-stayed bridges based on vehicle-bridge interaction theory LI Zichao1,2,3, LI Jian’an1,2,3, FENG Dongming1,2,3 In order to analyze the impact effect of vehicle loads on the cables of cable-stayed bridges, a domestic in-service cable-stayed bridge and a certain type of five axle load vehicle were studied. The dynamic response and impact coefficient of the cables under different working conditions were analyzed using finite element method. The calculation results were compared with the current national standards, and a recommended value for the dynamic impact coefficient of the cables was proposed. The simulation case considers the impact of vehicle speed (50km/h-120km/h), road level (smooth, Class A, Class B, Class C), and vehicle lateral position on the results. The research results indicate that the dynamic impact coefficient of the cable obtained through finite element analysis is greater than the value in the current specifications. As the road level increases, the impact coefficient increases. The impact effect generated by vehicles on the edge lane is greater than that on the middle lane. The influence of changes in vehicle speed on the dynamic impact coefficient of cables at different positions is not consistent. With the same working conditions, the dynamic impact coefficient of short cables is larger. Research has found that road surface grade is the main factor affecting the dynamic impact coefficient of cables. Therefore, it is recommended to take values for the impact coefficient based on road surface grade. The specific recommended values are: 0.08 for smooth road surface, 0.15 for Class A, 0.25 for Class B, and 0.4 for Class C, respectively. 2024 Vol. 43 (7): 67-74 [Abstract] ( 115 ) HTML (1 KB)  PDF (2839 KB)  ( 75 ) 75 Determination of POD of AE wave source based on phononic crystals LI Hongyu, ZENG Xiangxing, ZHANG Lu Acoustic emission testing (AE) is a nondestructive method for evaluating material status that involves the acquisition and analysis of signals produced by damage. However, the unknown AE source during testing poses a challenge to the study of probability of detection (POD). Moreover, the reliability of the detection results when utilizing acoustic emission to identify interior material degradation can be directly influenced by the acoustic emission source, making the AE source's detection probability a crucial consideration in acoustic emission detection. In this study, we use the features of phononic crystal to form a physical stopband to filter out the noise signals. Then the acoustic emission signal due to the crack growth of aluminum metal compact tensile specimens under cyclic loading can be obtained. To further explore the influence of threshold level and systematic filter frequency on the POD, the parametric study was conducted. The AE source related POD was estimated experimentally, and the POD increases with the growth of fatigue cracks, herein, the peak POD happens in the process of cracking other than the end stage. In addition, with the proper selection of the threshold and filters, the AE results can be improved more reliable. Therefore, it is essential to assess the POD for the AE method. 2024 Vol. 43 (7): 75-83 [Abstract] ( 63 ) HTML (1 KB)  PDF (2853 KB)  ( 86 ) 84 TRPCA rolling bearing fault feature extraction method with joint constraints of L 1,1,2 norm and tensor kernel norm under variable rotating speed WANG Ran1, CAO Xu1, ZHANG Junwu1, YU Liang2 As one of the important components of rotating mechanical equipment, the effective extraction of fault features from rolling bearings is of great importance to ensure the regular operation of mechanical equipment. In practical applications, rolling bearings usually operate at variable speeds, and the non-stationary signal of the bearings collected by a single sensor are often covered by severe background noise, making the task of fault feature extraction very difficult. This paper proposes a robust fault feature extraction method based on time-frequency analysis under variable speed conditions. First, the time-frequency representation (TFR) is used as frontal slices to construct the tensor, and explore the tubewise sparsity of time-varying fault features and the low rank property of the background noise in the tensor domain. Then, the tensor robust principal component analysis (TRPCA) with joint constraints of norm and tensor nuclear norm is used to extract the fault feature tensor, obtaining a tubewise sparse fault feature tensor. Finally, the extracted fault feature tensor is fused the channel index to get a time-frequency representation that can effectively represent the fault features. Simulation and experimental analyses verify the effectiveness of this method in bearing fault feature extraction. 2024 Vol. 43 (7): 84-93 [Abstract] ( 77 ) HTML (1 KB)  PDF (4256 KB)  ( 46 ) 94 Optimization method of substation structure based on improved sparrow search algorithm ZHANG Yingchun1,2, JIANG Lan1,2, TANG Bo1,2, CHEN Xi3, HU Hui4 In order to solve the optimization problem in the design of substation structures, the improved sparrow search algorithm was used for its optimization design. The Circle chaotic map was introduced into the basic sparrow search algorithm to improve the diversity of the population and the global search ability of the algorithm. The firefly algorithm was introduced to update the sparrow search algorithm to make it easy to jump out of the local optimum. A mathematical model of size optimization was established, and the penalty function method was utilized to deal with constraints. The improved algorithm was first used to analyze typical truss examples to prove its stability and effectiveness, and then applied to the optimization design of substation frames. The results show that the improved sparrow search algorithm can effectively improve the optimization effect of substation structures. 2024 Vol. 43 (7): 94-101 [Abstract] ( 78 ) HTML (1 KB)  PDF (2502 KB)  ( 12 ) 102 Effects of cage pocket shape on dynamic performance of high-speed angular contact ball bearing cage CHEN Shijin, ZOU Dongliang, WANG Yakun, CAI Dongming The dynamic numerical simulation models of angular contact ball bearings with square, round and spherical pocket cages are established, respectively. The accuracy of the model is verified by the experimental results. The cage dynamics with three different pocket shapes under different clearance ratios is analyzed. It is found that the movement stability of spherical pocket cages is significantly better than that of square and cylindrical pocket cages, and when the clearance ratio is less than 1, the movement stability of the cylindrical pocket cage is better than that of the square cage, on the contrary, the square cage is more stable. The movement range of the spherical pocket cage is determined by the pocket clearance, and the square and cylindrical pocket cages are determined by the guide clearance. With the increase of the clearance ratio, the axial swing range of the cage gradually increases. The axial swing range of the square, cylindrical and spherical pocket cages decreases successively. The wear rate of the cage is negatively correlate with its motion stability, and the wear rate of the spherical pocket cage is higher than the other two cages. 2024 Vol. 43 (7): 102-114 [Abstract] ( 58 ) HTML (1 KB)  PDF (5650 KB)  ( 46 ) 115 Test and numerical study on seismic performance of demountable and replaceable steel beams connected with T-shape steel MEN Jinjie1, ZHANG Qian1, LI Jiafu2, WANG Jiachen1, ZHANG Huihuang1, XU Chao2 This paper proposed a replaceable steel beam connected by T-shape steel plate. The T-shape connections dissipate the seismic energy under earthquakes, and be replaced after earthquakes to achieve the restoration of structural function. A yielding mechanism in which the T-shaped connections concentrate on damage dissipation and the central and cantilever sections of the steel beam remain elastic is achieved by rationally designing the bending capacity relationship between the T-shaped connections, the central section and the cantilever section of the steel beam and by defining the range of values for the design capacity weakening coefficient. To achieve the optimal damage and energy dissipation, four T-shape connections with different cross-sections and different materials for webs were designed. Pseudo static test and finite element analysis were carried out on replaceable steel beam specimens. Results show that the replaceable steel beams with T-shape connections can achieve the expected yielding mechanism and achieve the purpose of concentrated energy dissipation in T-shape connections. The residual deformation of the webs and bolt deformation values could allow the dismantling and replacement to be carried out. The structural function remains consistent after replacement, which indicates that the desirable replaceable mechanism is achieved. T-shape connectors with dog-bone web sections have more uniform plastic deformation, larger energy-consuming areas and an increase in energy-consuming efficiency of approximately 30%, with little difference in dismantling and replacement time and residual deformation compared to normal sections, so it is recommended that dog-bone sections be used for webs. Low yield point steel can improve the energy dissipation efficiency by about 40%, and can be selected for T-connections webs with reasonable values of the design load factor. Finally, based on the test and finite element results, and considering the dismantling and replacement of the T-shape connections and material utilization, it is recommended that the weakening coefficient of design load-bearing capacity be taken as 0.65~0.85. 2024 Vol. 43 (7): 115-125 [Abstract] ( 69 ) HTML (1 KB)  PDF (4713 KB)  ( 86 ) 126 Aerodynamic optimization of corner slotting in CAARC model based on LES XU Zhouyang, LUO Kaiwen, YANG Yi Super high-rise buildings are wind-sensitive structures, and appropriate aerodynamic optimization of building shape can effectively reduce the structural wind load and wind-induced response. Based on the large eddy simulation (LES) method, a new inflow turbulence generation - the NSRFG (Narrow band Synthesis Random Flow Generation) were used to investigate the effects of corner aerodynamic modification of the standard high-rise building model. First, the CAARC high-rise building standard model flow simulation was carried out, and the simulation results were compared with the wind tunnel test results to verify the applicability of the NSRFG method; then, based on the CAARC model, totally 4 corner modification schemes were designed and the base moments power spectrum were obtained through the LES simulation to estimate the top displacement and peak acceleration responses of the building. The results showed that: (1) For the standard high-rise building model with rectangular section, regardless of prototype or 4 modification schemes, the cross-wind fluctuation and peak acceleration are larger than that of the along-wind. (2) Compared with the prototype, all 4 modification schemes can reduce the wind-induced vibration response in along-wind and cross-wind directions, among which the corner slotting has the best optimization performance on along-wind response and the circumferential slotting has the best optimization performance on cross-wind response; (3) The optimization performance of the 4 modification schemes for the cross-wind response is obviously better than that for the along-wind response. Among the schemes, the circumferential slotting is the best, which can reduce the cross-wind fluctuating displacement and peak acceleration by 28.4% and 32.8%, respectively. Therefore, the circumferential slotting scheme is suggested to reduce the cross-wind response of super high-rise buildings with rectangular section. 2024 Vol. 43 (7): 126-133 [Abstract] ( 65 ) HTML (1 KB)  PDF (3351 KB)  ( 18 ) 134 Numerical simulation and seismic response characteristics of prefabricated assembled concrete filled steel tube columns with different connection constructions CHEN Tingdi1, WANG Shengbin2, FENG Keyan3, LI Jianzhong1 The presented paper investigates the seismic performance of prefabricated concrete filled steel tube (CFT) columns with two typical column-footing connections: socket connection (SC) and hybrid connection (HC). Finite element models for both SC and HC columns were established in OpenSees software. The SC model is able to simulate the bond-slip between the embedded steel tube and its surrounding concrete, the local buckling and the tearing; while the HC model can simulate the rocking behavior at the column-footing interface. The effectiveness of both models was validated through previous experimental data. Then analyses were conducted to investigate the dynamic performance of a 4-span continuous bridge with the single-column piers with the HC, SC and post-tensioned SC connections, respectively. The results show that both the SC and post-tensioned SC columns experience steel tube buckling when peak ground acceleration (PGA) reaches about 0.4g, resulting in a reduction in the horizontal stiffness and an increase in the residual displacement. Moreover, the damage caused by steel tube buckling in the post-tensioned SC columns is more severe, and with the further increase of PGA, the self-centering capacity provided by the post-tensioning gradually becomes evident. When the PGA reaches 0.6g, the residual drift of post-tensioned SC column is only 62% of that in the SC column. The HC column sustains less damage under strong earthquake excitations, with the residual drift less than 0.2%. Thus, it has better self-centering capacity than both the SC connection columns. 2024 Vol. 43 (7): 134-143 [Abstract] ( 49 ) HTML (1 KB)  PDF (4348 KB)  ( 36 ) 144 Reliability analysis of non-stationary buffeting of large-span bridge girder under a strong wind action SUN Bo1, YE Zeyi1, RUAN Weidong1, ZHANG Xinjun1, YANG Mingguan2 Buffeting reliability assessment is of vital importance to the safety insurance of long-span bridges under strong winds. A comprehensive nonstationary buffeting reliability analysis approach for the long-span bridge girder is proposed based on the nonstationary wind field model and the refined time-domain buffeting analysis process, considering the nonstationary and non-Gaussian characteristics of the buffeting response as well. The non-stationary fluctuating wind speed is simulated by combining the Weighted Amplitude Wave Superposition (WAWS) method and uniform modulation model based on the evolutionary spectrum theory. The static wind force is computed by the design code. The non-stationary buffeting force is obtained by the quasi-steady aerodynamic theory with the aerodynamic admittance formula for error correction consideration. The aerodynamic self-excited force is realized by introducing the aerodynamic stiffness and damping matrixes. Gaussian translation is applied on the buffeting response obtained from the refined finite element analysis using the Winterstein model. The dynamic reliability of nonstationary buffeting is obtained by the first overpass probability based on the Poisson assumption and the time-variant property of the response variance is considered. The proposed methodology is applied to evaluate the buffeting reliability of a long-span cable-stayed bridge under strong wind as a case study. 2024 Vol. 43 (7): 144-154 [Abstract] ( 75 ) HTML (1 KB)  PDF (4793 KB)  ( 22 ) 155 Finite element model correction of super long-span suspension bridge based on RBFNN-ISSA WANG Qishun1,2, HE Wei3, WU Xin1,2, GUO Weiqi1,3, LEI Shuncheng1,2 Aiming at the problem of finite element model updating for a class of complex structures of long-span suspension bridges, a finite element model updating method based on radial basis function neural network (RBFNN) substructure surrogate model and improved sparrow search algorithm (ISSA) is proposed. Firstly, the initial finite element model of a long-span suspension bridge is established by using the general finite element software based on the bridge drawing data, and the training samples of the material parameter structure response of the substructure are generated according to the Latin hypercube sampling principle. The initial finite element model is deconstructed and reconstructed by RBF neural network and substructure simulation method, and the surrogate model of material parameter structure response is fitted. Secondly, the finite element model parameter correction mathematical optimization model considering the minimum deflection and modal frequency error of the main beam is established. The standard sparrow search algorithm is improved by using tent chaotic mapping and golden sine strategy, and the Cauchy distribution function and greedy retention strategy are introduced to disturb each generation of sparrow population to solve the finite element model correction mathematical optimization problem with combined static and dynamic characteristics. Finally, taking Yueyang Hangrui Dongting Lake Bridge as the engineering background, the load test of suspension bridge is carried out, and the feasibility of this method is verified by the measured bridge response data. The results show that the model updating method based on RBF neural network and substructure method proposed in this paper can establish a suspension bridge structure surrogate model with high fitting accuracy; Compared with the standard RBF neural network, support vector machine and Kriging model, the modified finite element model based on substructure RBF neural network and improved sparrow search algorithm significantly improves the simulation accuracy of the actual structure. Compared with the measured data, the relative errors of the theoretical deflection values of 13 effective measurement points of the modified finite element model under two-stage static loading conditions are reduced by more than 25%, The average relative error of the first eight modal frequencies decreased from -6.83% to -2.38%. The MAC value results verified that the modified model could accurately reflect the actual vibration state of the bridge, and effectively improved the calculation distortion of the initial finite element model; In addition, the improved sparrow search algorithm based on hybrid strategy has better convergence efficiency and stability for the optimization of finite element model correction parameters.. 2024 Vol. 43 (7): 155-167 [Abstract] ( 73 ) HTML (1 KB)  PDF (4203 KB)  ( 31 ) 168 Chaos and bifurcation of Mathieu-Duffing system with square damping term XIE Jiaquan1,2, WANG Haijun1,2, SHI Wei2,3, ZHANG Jiale1,2, HUO Yiting1,2, CAO Jialin1,2, GAO Qiang1,2 The purpose of this paper is to study the resonance and chaos of Mathieu Duffing system with square damping term. The amplitude frequency and phase frequency characteristics of the main resonance of the system under the combined excitation of parameters and force are explored by using the multi-scale method. Based on Lyapunov's first method, the stability conditions of the steady solution are given and the periodic solution branches of the system are determined. According to the Parametric equation of the heteroclinic orbits of the system, the necessary conditions for the heteroclinic orbits to cross and the chaos of the system are derived. According to the bifurcation diagram, phase trajectory diagram, and Poincare cross-section were used to study the effects of excitation amplitude and frequency on the chaotic motion behavior of the system. It was confirmed that changes in excitation frequency and amplitude can lead to the system entering a chaotic state through period doubling bifurcation. 2024 Vol. 43 (7): 168-174 [Abstract] ( 136 ) HTML (1 KB)  PDF (1435 KB)  ( 71 ) 175 Vibration suppression method for space-flexible manipulator using fuzzy compensation sliding mode controller SHANG Dongyang1, LI Xiaopeng1, YIN Meng2, LI Fanjie1, ZHOU Sainan1 Space-flexible manipulators can be installed on the space station to assist astronauts in on-orbit maintenance, spacecraft rendezvous as well as docking, and space junk capture. Because of its slender structure, the space-flexible manipulator will vibrate in the process of moving, which will affect the operation's precision and flight safety. In order to reduce the vibration of space-flexible manipulators, fuzzy compensation sliding mode control strategy is proposed to control the rotating motion of space-flexible manipulators. The vibration is weakened indirectly by improving the rotation control precision of space-flexible manipulators. In this paper, the deformation of space-flexible manipulators is described based on the assumption mode method. The Lagrange principle is used to establish dynamic equations coupled with modal and angle which considers the two-dimensional deformation. Then, the universal approximation characteristic of fuzzy rules is used to identify and compensate for the uncertain components of dynamic models including flexible nonlinear terms and external disturbances. Then, according to the Lyapunov function, the control law and adaptive law of fuzzy compensation sliding mode control strategy are designed to ensure the closed-loop stability of space-flexible manipulators. Finally, the simulation and physical prototype control experiments of space-flexible manipulators are carried out. The experimental results show that the fuzzy compensation sliding mode control strategy can effectively improve the rotation control precision of space-flexible manipulators and indirectly reduce the vibration amplitude. Compared with the traditional sliding mode control strategy, the proposed control strategy can reduce the mean value of the absolute value of the angular tracking error by 17.86% and the standard deviation of the lateral acceleration by 31.91%. 2024 Vol. 43 (7): 175-185 [Abstract] ( 94 ) HTML (1 KB)  PDF (4558 KB)  ( 48 ) 186 Deep anomaly detection method for low-rotating speed rolling bearing faults of aero-engine KANG Yuxiang1, CHEN Guo2, SHENG Jiajiu1, WANG Hao3, WEI Xunkai3 Aiming at the problem that the faults of aero-engine rolling bearings are difficult to detect at low speed, a deep support vector description method based on Transformer framework was proposed to detect the faults of low speed rolling bearings. Firstly, a vibration feature extraction backbone network based on Transformer model is constructed. Then, the extracted features are input into a three-layer autoencoder structure, which is used to calculate the loss function of the network model. In order to reduce the amount of network calculation and improve the training speed, the frequency spectrum results obtained by Fast Fourier Transform (FFT) of the vibration acceleration time domain signal of rolling bearing were used as the input of the network in the preprocessing, and the model training was completed only by normal data. Finally, the experiments were carried out on an aero-engine rotor tester with casing and a real aero-engine. The results show that the proposed method can accurately detect the faults of low speed rolling bearings, and the detection accuracy is 93% and 100%, respectively, which fully indicates that the proposed method has good anomaly detection ability and application value. 2024 Vol. 43 (7): 186-195 [Abstract] ( 91 ) HTML (1 KB)  PDF (3349 KB)  ( 99 ) 196 Automatic identification method of modal parameters of offshore platform structure based on IEWT LENG Jiancheng1, 2, DIAO Kaixin1, PANG Zhe1, FENG Huiyu1 An improved empirical wavelet transform (IEWT) method for structural modal parameter automatic identification is proposed to address the issue of misjudgment of spectral segmentation boundaries in processing low signal-to-noise ratio signals using empirical wavelet transform (EWT). Firstly, the cross power spectrum matrix of the signal is calculated, the singular value decomposition method and the scale space method are used to determine the spectral division boundaries, and the signal is decomposed into several intrinsic mode function components. Then, the random decrement technology and Hilbert transform are combined to realize the automatic identification of modal parameters. The IEWT method was used to identify modal parameters of free vibration response signals and ASCE Benchmark model signals, and compared with the EWT method, AR-EWT and WT method, the result shows that the IEWT method can adaptively determine the spectral segmentation boundaries and has high identification accuracy for modal parameters such as frequency and damping ratio of the structure. Further, this method is applied to identify modal parameters of laboratory offshore platform. It has been proven that this method can be used for modal parameter identification of low-frequency structures in complex noise environments. 2024 Vol. 43 (7): 196-204 [Abstract] ( 62 ) HTML (1 KB)  PDF (2504 KB)  ( 15 ) 205 Sensitivity analysis of 3-D flutter of large-span bridge based on differential method WENG Xiangying1, DONG Rui2, GE Yaojun3 With the ability of indicating the dependency of critical flutter wind speed on design parameters, bridge flutter sensitivity is an important tool for long-span bridge aerodynamic optimizations. To assist bridge designers accurately and efficiently acquiring the influence of structural dynamic characteristics and flutter derivatives on the flutter performance of long-span bridges in the preliminary design stage, a three-dimensional local flutter sensitivity analysis method based on direct differentiation is proposed. By considering the orthogonality of the left and right eigenvectors of the system matrix, a set of normalized conditions for the multimode coupled bridge flutter is constructed under small variations of design parameters. Combined with the flutter critical condition, the sensitivity of the system eigenvalues and flutter critical wind speed to the design parameters are obtained. To verify the method, the flutter sensitivity of a simple supported beam with an ideal thin flat plate cross-section is carried out and compared with the numerical parameter study. It finds the two results agree well. The flutter sensitivity analysis of a large-span suspension bridge is conducted. The sensitivity results show that for a large-span bridge with a streamlined girder, the first symmetric vertical bending and first symmetric torsion modes have the greatest impact on bridge flutter. Optimization measures including increment of the damping ratio, modal mass, and fundamental frequency ratio of torsion to vertical bending mode will have positive influence on the bridge critical flutter wind speed. Among the flutter derivatives, has the most significant impact on the critical flutter wind speed, followed by , and , while the others can be ignored. 2024 Vol. 43 (7): 205-213 [Abstract] ( 57 ) HTML (1 KB)  PDF (2023 KB)  ( 86 ) 214 Dynamic tracking performance analysis of liquid-film seal based on thermal-fluid-structure coupling SONG Yong1, YU Bo1, 2, HAO Muming2, WANG Chenyin2, LI Tianzhao2, REN Baojie3 To thoroughly examine the dynamic tracking features of liquid film seals in the context of thermo-fluid-solid coupling, the small perturbation method and thermo-hydrodynamic lubrication theory are utilized. Accounting for non-compensated ring axial vibration and angular yaw, a motion equation with three degrees of freedom is formulated for the compensation ring. The influence of mechanical component parameters, operating condition parameters, and structural parameters on dynamic tracking is methodically compared and analyzed within both pure flow field and thermo-fluid-solid coupling models. The observations reveal that the disturbance values for liquid film seals computed under the thermo-fluid-solid coupling model are slightly less compared to those in the pure flow field model. Increasing excitation amplitude, spring stiffness, and O-ring damping contributes to heightened disturbance, consequently diminishing dynamic tracking effectiveness. In contrast, decreasing the rotational speed and elevating the medium pressure lead to an augmentation of dynamic characteristic coefficients, thereby enhancing dynamic tracking capabilities. Streamlining the number of grooves bolsters dynamic tracking, and with a fixed groove count, adopting structural parameters featuring a groove depth of 17μm, a groove dam ratio of 0.8, and a helix angle of 22° yields optimal dynamic tracking performance. 2024 Vol. 43 (7): 214-222 [Abstract] ( 68 ) HTML (1 KB)  PDF (4533 KB)  ( 12 ) 223 Energy transfer characteristics of fast compressed P1 waves on interface between saturated frozen soil and elastic bedrock MA Qiang1, 2, JIANG Huipeng1, ZHOU Fengxi3, JIANG Ningshan1, 2 Based on the propagation theory of elastic waves in frozen saturated porous media and single-phase elastic media, the energy transmission problem of the fast compressional P1-wave with the maximum propagation velocity in saturated frozen soil was selected at the interface between saturated frozen soil and elastic bedrock. According to the boundary conditions at the interface, the analytical expressions of transmitted and reflected amplitude ratio and energy ratio of the fast compressional P1-wave from saturated frozen soil to elastic bedrock are derived. The incident energy relationship of fast compressional P1-wave at the interface between saturated frozen soil and elastic bedrock with incident angle, frequency, temperature (ice content), porosity, cementation parameter and contact parameter is studied. The results show that there is only a compression wave when the incident angle is 0, and the transmitted P wave disappears after reaching the critical angle. Various waves have different degrees of pulses when reaching the critical angle, among which the reflected P1 wave is the most significant. As the cementation parameters, porosity and contact parameters increase, the critical angle appears earlier. The incident frequency only greatly influences the energy-reflected ratio of reflected P2, P3 and S2 waves. When the temperature and ice content are low or high, it is not conducive to the energy generation of reflected S2 waves. 2024 Vol. 43 (7): 223-238 [Abstract] ( 76 ) HTML (1 KB)  PDF (1761 KB)  ( 104 ) 239 Attenuation characteristics of bubble curtain on underwater shock waves under different air flow rates MA Chengshuai1, WU Hongbo1, WANG Yinjun2, LU Shaofeng3, LI Jirui3, CAI Xinyuan1, CHEN Zhengyan1 In order to study the attenuation characteristics of the bubble curtain on the underwater shock wave under different air flow rates, the morphological changes of the bubble curtain after the shock wave were explored by using high-speed photography, and the analysis was carried out based on the time-history curve of the shock wave pressure. The results show that the bubbles in the bubble curtain will expand and contract several times after being subjected to shock wave. With the increase of gas flow rate, the maximum diameter of bubble expansion increases and the first period of bubble expansion and contraction becomes longer. And the bubble curtain has a strong damping effect on the underwater shock wave pressure. The larger the gas flow rate rises, the more obvious the peak attenuation of shock wave pressure is. Under the gas flow rate of 40L/min, the peak attenuation of shock wave pressure is as high as 88.98%. When the gas flow rate is greater than 20L/min, the attenuation amplitude of shock wave impulse is greater than 50%. Based on the curve fitting of the relationship between the gas flow rate and the drop range of the peak pressure, the empirical equation suitable for the working condition is put forward in order to guide the practical engineering. 2024 Vol. 43 (7): 239-244 [Abstract] ( 107 ) HTML (1 KB)  PDF (2180 KB)  ( 27 ) 245 Large-scale dynamic triaxial tests and dynamic characteristics of clay contaminated round gravel under subway cyclic load MA Shaokun1,2, TIAN Fapai1, HUANG Haijun1, ZHANG Jiabing1,2, DUAN Zhibo3, GONG Jian1,2 In order to investigate the long-term dynamic properties of clay-fouled round under cyclic subway loading, a series of saturated undrained dynamic triaxial tests were carried out by utilizing the GDS large-scale triaxial cyclic test system. The influence of clay fouling level (VCI) on round gravel's long-term dynamic properties under different confining pressures and dynamic stress amplitudes was analyzed. The experimental results show that with the increase of VCI, the cumulative plastic strain of the specimen shows a tendency of increasing and then decreasing, and the fouled clay changes from lubrication to filling. When the confining pressure is 100 kPa, the cut-off VCI is 30%, and when the confining pressure is 200 kPa and 300 kPa, the cut-off VCI is 20%. VCI has a large impact on shallow buried subway tunnels (σ3= 100 kPa), which threatens the safety of traveling, while it has a small impact on deep buried subway tunnels (σ3= 200 kPa, 300 kPa), which makes the subway operation relatively safe. With the increase of VCI, the elastic strain and dynamic pore-pressure ratio of the specimens first increased and then decreased, while the resilience modulus first decreased and then increased. However, the trends of all three changes become more obvious with the decrease of confining pressure and the increase of dynamic stress amplitude. Generally, the research results can be used as a reference for designing subway roadbed structures and their post-construction settlement predictions. 2024 Vol. 43 (7): 245-254 [Abstract] ( 59 ) HTML (1 KB)  PDF (4707 KB)  ( 14 ) 255 Composite fault diagnosis of rolling bearing based on iterative enhanced variational mode extraction ZHANG Jiajun1, MA Ping1, ZHANG Hai2, ZHANG Hongli1 To solve the problem of insufficient extraction capacity of variational mode extraction for multi-component composite faults and the existence of two hyperparameter optimizations of center frequency and balance factor, an iterative enhanced variational mode extraction (IEVM) method for composite fault diagnosis of rolling bearing was proposed. Firstly, an iterative variational mode extraction method (IVME) was proposed to optimize the initial center frequency of VME by introducing the convergence phenomenon of center frequency trend, so that it can find an appropriate initial center frequency to extract and add a new convergence criterion to extract the signal iteratively; Then, a plurality of component signals were obtained by optimizing the balance factor of IVME, and the optimal component was selected for reconstruction by means of the Graph-Laplace energy index; Secondly, in order to extract the main period in the composite fault signal, an enhanced minimum noise amplitude deconvolution (EMNAD) method was proposed, which combines enhanced algorithm subtraction to reduce the noise and enhance the relatively weak periodic signal; Finally, the composite fault diagnosis of rolling bearing was realized by fusion of square envelope spectrum. The proposed method was applied to the composite fault diagnosis of rolling bearing, and the effectiveness and robustness of the proposed IEVME method have been verified by simulation and example signals. The proposed method was compared with the existing multiple methods, and the results show that the proposed IEVME method has higher accuracy and better effect. 2024 Vol. 43 (7): 255-265 [Abstract] ( 76 ) HTML (1 KB)  PDF (3404 KB)  ( 34 ) 266 Performance-based design method for hybrid coupled PEC wall structure based on reasonable failure modes ZHOU Qiaoling1,2, ZHAO Shixing1, SU Mingzhou2, SHI Yun3 Based on the concept of performance-based design, a performance-based design method of the hybrid coupled PEC wall based on the reasonable failure mode is proposed. The performance goal is to achieve a reasonable failure mode when the structure reaches the target displacement. The design base shear force is determined on the basis of the principle of energy balance, and a lateral force distribution in accordance with the failure mode is given. According to the given plastic coupling ratio, the internal force requirements of the steel coupling beams and the strengthening section at the bottom of the PEC wall piers are obtained. The plastic design method is used to design the steel coupling beams and the strengthening section at the bottom of the PEC wall piers, and the elastic design method is used to design the non-strengthening section of the PEC wall piers, so as to achieve the expected performance goal. According to the proposed performance-based design method based on the reasonable failure mode, a 12-story hybrid coupled PEC wall structure is designed. And the pushover analysis and elastic-plastic dynamic time history analysis are conducted to verify the accuracy of the method. The hybrid coupled PEC wall structure designed by the performance-based design method of reasonable failure mode has good seismic performance. Under the earthquake, all the steel coupling beams first suffered from shear yielding and then the plastic hinges formed at the bottom of the PEC wall piers. The distribution and development of plastic hinges meet expectations, and the design goal of a “two-stage energy dissipation system” is realized. 2024 Vol. 43 (7): 266-277 [Abstract] ( 42 ) HTML (1 KB)  PDF (4098 KB)  ( 24 ) 278 Coupled vibration characteristics and vibration control of roll system of 20-high rolling mill KONG Xianglan1,2, HE Dongping1,2, XU Huidong1,2, WANG Tao1,2, HUANG Qingxue1,2 Precision Ultra-thin strips are widely used in high technology fields such as micro-manufacturing and micro-electronics because of their high precision, corrosion resistance and excellent surface finish. The coupling vibration of the roll system of a twenty-roll mill has an important impact on the production of Ultra-thin strips. Considering the nonlinear rolling interface formed by the variations of rolling process and lubrication state, a coupling dynamic model of the roll system of twenty-high rolling mill is established. The amplitude-frequency characteristic equations of the primary resonance and internal resonance are solved by applying the multi-scale method, and the effects of different parameters on the amplitude-frequency characteristic curves are analyzed. The relationship between different parameters and the system bifurcation is explored based on the singularity theory. Meanwhile, the system stability is judged and analyzed according to the Lyapunov’s first approximation stability criterion, combined with the phase trajectory diagram of the system dynamic phase plane. Afterward, a state feedback controller is designed based on the principle of Washout filter controller, and the influence of control gain on the amplitude-frequency characteristics is analyzed by transforming the state space expression of the system. Simulation and comparison verify the feasibility and effectiveness of the designed controller by using time domain diagram, phase diagram, spectrum diagram and Poincaré cross-section diagram, which provides some theoretical guidance for the study of twenty-roll mill vibration and its control. 2024 Vol. 43 (7): 278-289 [Abstract] ( 70 ) HTML (1 KB)  PDF (3211 KB)  ( 98 ) 290 Rolling bearing fault diagnosis based on multi-source domain adaptive residual network GAO Xuejin1,2,3,4, ZHANG Zhenhua1,2,3,4, GAO Huihui1,2,3,4, QI Yongsheng5 Aiming at the weak applicability of the traditional unsupervised domain adaptive method to multi-condition rolling bearing fault diagnosis scenarios, a Multi-source Domain Adaptive Residual Network (MDARN) was proposed. By aligning Correlated subdomains from multiple source domains, thus improving the fault diagnosis performance of the model under multiple operating conditions. First, the ResNeXt residual network is used to fully extract transferable features from the source domain and the target domain; then, the local maximum mean difference (LMMD) criterion is introduced to align the relevant subdomains in the target domain based on the subdomains of the two source domains, reducing The distribution difference between the relevant sub-domains and the global domain; finally, the proposed method is verified experimentally by using the bearing data set of Case Western Reserve University and the real bearing vibration data set generated by the MFS mechanical comprehensive fault test bench. The results show that the average fault diagnosis accuracy of this method is as high as 99.76% under multiple working conditions. Compared with the existing representative methods, the proposed method has better fault diagnosis effect. 2024 Vol. 43 (7): 290-299 [Abstract] ( 121 ) HTML (1 KB)  PDF (2281 KB)  ( 50 ) 300 Dynamic study of high-static-low-dynamic suspension for electromagnetic underwater acoustic transducers SUN Shitao, YAO Yuhui, ZHANG Xi, LI Hongguang To address the problem that the linear suspension cannot balance the reduction of the resonance frequency and the bearing of large hydrostatic pressure for the electromagnetic acoustic transducer, a high-static-low-dynamic suspension device was designed and its influence on the sound radiation performance of the transducer was analyzed. The system dynamics model and the differential equations of dynamic characteristics were established, and the changes of sound source level and resonance frequency of the transducer system before and after introducing nonlinear stiffness were simulated and analyzed, and the influence of input voltage on the resonance frequency of the transducer system was studied. The differences between different high-static-low-dynamic systems are investigated. The natural frequency and acceleration conductor of the suspension device before and after introducing high-static-low-dynamic stiffness were obtained by hammering test. The research results show that compared with the original linear suspension, the high-static-low-dynamic suspension has a lower intrinsic frequency and higher acceleration in the low frequency band when subjected to the same load. The introduction of a suspension device with high-static-low-dynamic stiffness characteristics into the electromagnetic transducer can obtain a lower resonance frequency than the original system, resulting in an improvement of the sound source level in the ultra-low frequency region. 2024 Vol. 43 (7): 300-307 [Abstract] ( 98 ) HTML (1 KB)  PDF (1670 KB)  ( 24 ) 308 Fault diagnosis of variable rotating speed rolling bearing based on EOE_LMD and order tracking analysis ZHANG Chao, MAIMAITIREYIMU Abulizi Vibration signal analysis is one of the important technical means in bearing fault diagnosis. The fault vibration signal of rolling bearing under the variable speed condition is a typical non-stationary signal, and there is also the problem of noise interference in the condition of small rotation frequency change, which makes the traditional time-frequency analysis technology difficult to apply. To solve this problem, a fault diagnosis method based on local mean decomposition (LMD) using empirical optimal envelope (EOE) and computing order tracking (COT) using piecewise linear interpolation was proposed. Firstly, the cut-off frequency and filtering order of the low-pass filter were determined to filter the vibration signal of the rolling bearing, and COT was performed on the filtered envelope signal to obtain the angular domain stationary envelope signal. Then, The local mean decomposition using empirical optimal envelope (EOE_LMD) was used to process the resampled stationary envelope signal to obtain several product function (PF) components. Finally, the information entropy and correlation coefficient of each component were calculated, and the appropriate component was selected for order analysis to judge the fault type of variable speed rolling bearing. The results show that the proposed method can eliminate the influence of speed fluctuation on fault feature extraction, and has good fault diagnosis ability for rolling bearings under different variable speed conditions. 2024 Vol. 43 (7): 308-316 [Abstract] ( 97 ) HTML (1 KB)  PDF (1438 KB)  ( 115 ) 317 Vibration characteristics of functionally graded graphene reinforced porous composite stepped cylindrical shell XU Hongda, WANG Yu, XU Ziqiang, JIA Xiaoyu, YU Xiaoguang The vibrational properties of functionally graded graphene platelet reinforced porous composites (FG-GPLRPC) stepped cylindrical shell were investigated in this study. First, the effective material properties of the FG-GPLRPC stepped cylindrical shell are obtained using the Halpin-Tsai micromechanical model as well as the open-cell body theory. Secondly, the energy expressions of the shell structure are derived based on the first-order shear deformation theory and the penalized parameter method. Finally, the Jacobi-Ritz method is used to establish the vibration control equation of the shell structure and to find the dimensionless frequency of the structure, which verifies the validity and correctness of the method. The results show that the mass fraction of graphene, porosity coefficient and boundary spring stiffness value have significant effects on the vibration characteristics, the number of layers has less effect on the vibration characteristics, the dimensional parameters have different effects on the vibration characteristics, and the variation law of the shell frequency decreases and then increases with the circumferential wave number is obtained. 2024 Vol. 43 (7): 317-326 [Abstract] ( 83 ) HTML (1 KB)  PDF (2645 KB)  ( 43 ) 327 Adaptive filtering method and application based on RNN REN Hongyi1, LIU Xiangyu1, XIAN Ganling1, LAN Jingyan1,2 At present, there are some defects in seismic wave filtering methods of earthquake engineering research field, such as human experience interference, peak spike, noise interference, etc. In this paper, a new adaptive filtering method is proposed by combining recursive least squares (RLS) algorithm and recurrent neural network (RNN) model. The results show that the new method performs filtering by setting adaptive adjustment filter parameters and the self-iteration algorithm. It is superior to the traditional filtering method recommended by the United States Geological Survey (USGS) in noise recognition ability and filtering speed, and can effectively reduce the distortion, damage and phase advance of the original waveform after filtering. At the same time, the adaptive filtering method was applied to near-field seismic records containing velocity pulses at different site classification of stations. The adaptive filtering method has been further proven to be effective. The research results provide a new idea and method for filtering analysis in the field of Earthquake engineering, and can also provide reference for seismic record processing and related applications. 2024 Vol. 43 (7): 327-333 [Abstract] ( 77 ) HTML (1 KB)  PDF (1964 KB)  ( 26 ) 334 Test study on influence line identification and load-bearing capacity rapid evaluation for continuous girder bridge ZHOU Yu1,2,3, SHANG Wenqi1,2, DI Shengkui3, ZHENG Xu4, HE Wenyu5 Aiming at the problems of heavy load standing and traffic obstruction in the process of bridge static load test, a rapid evaluation method of bridge bearing capacity based on influence line is proposed by taking advantage of the bridge influence line to completely reflect the bending stiffness of each section of the structure. In this method, the bridge time history response including bridge influence line information, structural dynamic components and vehicle multiaxial effect is obtained by using the mobile loading of a single heavy vehicle, and the dynamic components in the bridge time history response are first stripped by variational mode decomposition. Secondly, a mathematical model of bridge influence line recognition is constructed according to the sampling frequency and vehicle wheelbase, so as to eliminate the vehicle multi-axis effect in the bridge time history response, and the stable solution of the bridge influence line is obtained by using Tikhonov regularity. Then, by carrying out virtual loading on the bridge influence line, the virtual static response of the bridge is reconstructed, and the traditional check coefficient method is used to evaluate the bearing capacity of the bridge. The effectiveness of the influence line identification method is verified by the numerical example of three-span variable section continuous girder bridge, and the accuracy of the influence line identification result is quantitatively evaluated by establishing the error index, so as to carry out static load test and rapid evaluation test research on the bearing capacity of a three-span continuous steel-concrete composite girder bridge, implement vehicle mobile loading in the preset lane, identify the deflection and strain influence line of the middle span of the bridge, and then the virtual loading study was carried out to further verify the feasibility and practicability of the proposed rapid evaluation method of carrying capacity, and to provide method support and case reference for the "lightweight" rapid screening of bridge carrying capacity. 2024 Vol. 43 (7): 334-344 [Abstract] ( 91 ) HTML (1 KB)  PDF (3335 KB)  ( 111 ) 345 Configuration design and analysis of helicopter crashworthiness components LU Zhilong In order to explore influence of different configuration parameters on a energy absorption performance of composite corrugated beams, the dynamic collapse tests were carried out for various configurations of corrugated beams, and the load-time curves and failure modes of various configurations of corrugated beams were given by analyzing the test phenomena and processing the test data. The transient impact process of the corrugated beam was simulated by the finite element software (ABAQUS), and the specific energy absorption (SEA) and the average load value were obtained, which were compared with the experimental results to verify the validity of the numerical model. Based on the experimental and numerical analysis results, the influence of the corrugated configuration on the peak load and energy absorption capacity of the corrugated beam is discussed, and the difference of energy absorption between different corrugated beams and the design of adding weak links is evaluated, which provides a reference for practical engineering design.The results indicate that when the critical stress equation of the corrugated beam under axial compressive load is used to set the height/amplitude ratio and wavelength/amplitude ratio of the corrugated beam in the corresponding relationship, the corrugated beam structure exhibits a relatively stable crushing process, which has certain application value;The R value of the corrugated web fillet not only affects the peak load and average load, but also has a certain relationship with the change of the failure mode of the corrugated beam. The R value of the weak fillet can better improve the peak load. 2024 Vol. 43 (7): 345-354 [Abstract] ( 121 ) HTML (1 KB)  PDF (4381 KB)  ( 56 ) 355 Experimental study on hydrodynamic characteristics of new pile-plate bridge structures impacted by plunging waves XU Pu1, ZHANG Shengyu1, ZHENG Zhongkai1, LIU Qiujiang2, QIU Junfeng2 Based on the new pile-plate bridge structure project of the coastal national highway in Fujian Province, the hydrodynamic experiments of the pile-plate bridge structure under the impact of plunging waves arewere conducted in the wave flume, . the The wave climbing height and the wave forces of the pile-plate bridge structure under the impact of three stages of plunging waves are were investigated, and compared to those under the impact of regular waves. The influence laws of the incident wave height, wave period, and depth of the water on the wave climbing height and the wave force are were analyzed. The results show that the hydrodynamic characteristics of the new pile-plate bridge structures impacted by the three stages of plunging waves are significantly different, there will beis evident wave climbing phenomenon in the about breaking and breaking stages, and the wave surface elevation after the climb of the plunging wave in the about breaking stage attains 1.99 times of the regular wave; the horizontal wave force of the plunging wave at the about breaking stage is the strongest, which is 4.48 times of the amplitude of the vertical wave force in the same stage, and can be 3.08 times of the horizontal wave force of the regular wave. The wave parameters and water depth significantly influence the hydrodynamic characteristics in three stages of plunging waves. With tThe increase of the incident wave height and water depth causes ,the wave surface elevation and vertical wave force in the breaking stage exceed other stages. The increase of wave period makes the wave surface elevation in the complete breaking stage and the vertical wave force in the about breaking stage exceed those in the breaking stage. 2024 Vol. 43 (7): 355-364 [Abstract] ( 75 ) HTML (1 KB)  PDF (3799 KB)  ( 65 )

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