In order to improve the energy dissipation capacity of the irregular steel joints of pseudo-classic architecture，the replaceable viscous damping device was set up at the location of decorated bracket to dissipate seismic energy. Six specimens of pseudo-classic architecture joints were designed and manufactured，including the single beam-column joint （SBJ） series and double beam-column joint （DBJ） series. The hysteretic curves and skeleton curves of the specimen and the viscous damper were obtained by the sine wave dynamic loading with displacement and frequency control，and the deformation and energy dissipation capacity of the specimen and the viscous damper were analyzed，respectively. The results indicate that the improved dynamic loading system has achieved good test results，and the failure mode of the irregular steel joint of pseudo-classic architecture is improved by installing a viscous damper at the decorated bracket position. The viscous damper has good working state after buckling in the plastic hinge area of the beam end of the specimen，and the hysteresis ring of the specimen becomes full gradually. The larger the damping coefficient of the damper，the fuller the hysteresis rings of the node and the stronger the energy dissipation capacity. With the increase of damping coefficient，the bearing capacity of specimens with controlled joints is increased by 18%~46% compared with that of without controlled，and the viscous damper increases the bearing capacity of specimens with double beam-column joints more significantly. The displacement ductility coefficient of the specimen is between 1.77 and 2.05，and the ductility of the specimen is slightly improved after the viscous damper is installed. The strength degradation coefficients are all about 1.0.

Aiming at the problems of bearings working in complex environments，where fault data are difficult to obtain in large quantities and the serious imbalance between the ratio of normal data and fault data resulting in insufficient in-depth model training and low diagnostic accuracy，a bearing fault diagnosis method based on LSGAN-Swin Transformer is proposed. The least-squares generative adversarial network is utilized to expand the imbalanced or lack of bearing dataset，and the windowed self-attentive network is introduced for bearing fault state identification. The proposed method is validated by using two date sets，and compared with SGAN and WGAN respectively. It is demonstrated that LSGAN generates data training models with higher accuracy. The proposed Swin Transformer （Swin-T） model is compared with CNN，AlexNet and SqueezeNet under small sample conditions，and the accuracy is improved by 34.85%，13.45%，and 12.95%，respectively. The classification effect of the model is evaluated by t-SNE visualization，and the results show that the LSGAN-Swin-T model can still meet the requirements in fault diagnosis better when the number of training samples is small，which provides a new idea for the research of bearing fault diagnosis under unbalanced data.

A large number of high-pier rigid frame bridges in the canyon areas are located in near-fault regions （hereinafter referred to as near-fault），and the seismic analyses should comprehensively consider the near-fault effect，site effect，and fluid-structure interaction when they are located in the water environment such as rivers，reservoirs，etc. Currently，most near-fault seismic records are used as consistent inputs，which may underestimate the seismic response of the bridges. At the same time，the discussion on the correlation between the seismic sources，site parameters，and seismic response of the bridges is unexplored. In this paper，the stochastic finite fault method and the boundary element method are combined to generate the multi-dimensional and multi-point ground motions of the overlying water-layer canyon sites near faults，and the analysis of the seismic response of the deep-water，large-span，high-pier rigid frame bridge in the near-fault canyon site is developed. The sensitivity of the response of piers and bearings to the seismic source and site parameters is investigated from the perspective of the whole physical process between the seismic source and the structure. The results indicate that the bridge response is most sensitive to the rupture surface size. On the whole，the influence of source parameters on the bridge response is more significant than that of site parameters. The site effect leads to the difference of the mean values of curvature ductility ratios of two main piers in longitudinal and transverse directions to be 85% and 88%. There are differences in the sensitivities of the main piers and bearings to each parameter. When the dip angle of the fault is between 33°~60°，the seismic response of the bridge shows a trend of increasing first and then decreasing，and the curvature ductility ratio of the main pier can differ by 35%. The water layer has an inhibitory effect on ground motions； however，the amplification effect of hydrodynamic pressures on the seismic response of the bridge is more prominent.

To accurately extract fault feature information under strong background noise，a multi-scale improved differential filter （MIDIF） is proposed for rotating machinery fault diagnosis. The rotating machinery vibration signal is decomposed into a series of multi-scale improved differential filter signals using MIDIF. In view of that the MIDIF filtered signals exhibit varying extents of validity in revealing fault features，a weighted reconstruction method using correlation analysis is proposed in which the weighted coefficients are counted and distributed to the corresponding MIDIF filtered signals to highlight the effective MIDIF filtered signals and weaken the invalid ones. The weighted coefficients are multiplied with the MIDIF filtered signals under different scales to produce transient impulse components. The fault types of rotating machines are inferred from the fault defect frequencies in the envelope spectrum of the transient impulses. The results show that MIDIF is more accurate in extracting fault features than multi-scale average combination different morphological filter （ACDIF） and multi-scale morphology gradient product operation （MGPO），and that it provides an effective method for rotating machinery fault diagnosis.

Based on the train-track coupling dynamics and probability density evolution theory，a random vibration model of train-track system considering both the crosswind and track irregularity is established. The N-dimensional hypercube point set is used to generate the discrete random frequency and phase representative point set. Based on the random harmonic function method and the harmonic superposition method，the random track irregularity excitation samples and the wind speed time-history samples are simulated respectively. The obtained two random excitations are introduced into the train-track coupling system to obtain the representative responses. The probability density evolution equation of representative response is solved using the bilateral difference method to obtain the time-varying probability density evolution distribution of the vibration response. The Monte Carlo method （MCM） is employed to verify the computational efficiency and accuracy of the proposed model. The results indicate that the probability density evolution method （PDEM） is appliable to the random analysis of vehicle-track system under double random excitations including crosswind and track irregularity. When the number of representative sample points is 300 and the screening radius is 17.7，a good calculation results can be obtained by the proposed model in this paper. The random response analysis regarding a single random input cannot express an accurate result of the vehicle-track system’s random dynamic characteristic，which indicates the required consideration of both random excitations of crosswind and track irregularity in the random vibration analysis of vehicle-track system.

Steel spring floating slab tracks are equipped to reduce the vibration impact on precision instruments along the metro lines，but the ground vibration would be amplified at the natural frequency of the tracks. In order to address the negative impact of natural frequency vibration amplification on the surrounding environment of floating slab track，a full frequency control method considering frequency matching for environmental vibration in collaboration with metro vibration sources and propagation paths is proposed，which is based on the theory of periodic structure bandgap structure. The effectiveness of this method is analyzed by establishing a three-dimensional metro train-floating slab track coupling model and a finite element analysis model of track bed-tunnel- soil-row piles. The research results show that the ground vibration can be reduced about 4~7 dB at the natural frequency of the floating slab track plate by adjusting the band gap range of periodic pile to 7~9 Hz，eliminating the adverse effect of vibration amplification at the natural frequency of the track. Compared to ordinary tracks，the environmental vibration comprehensive control method proposed in this article has good vibration control effects and can effectively reduce the vibration level of sensitive points on the ground in the full frequency range.

In order to study the suppression mechanism of vortex-induced vibration （VIV） by adding aerodynamic countermeasures such as guide vanes near maintenance rails and spoilers on handrails，the displacement and pressure measurement on a large-scale sectional model was conducted in wind tunnel tests. Based on the spatial-temporal distribution and statistical characteristics of surface pressure，an aerodynamic wave hypothesis is proposed and further verified using the spectral proper orthogonal decomposition （SPOD） method. Moreover，the complex spatial-temporal pressure field is quantified and deconstructed with the spatial-temporal energy spectrum of the aerodynamic force，revealing the mechanism of vertical VIVs as well as its suppression by aerodynamic countermeasures in a streamlined box girder. The results reveal that there are three lock-in ranges of vertical VIVs for the original girder while the largest VIV response appears in the 3rd order lock-in range. The addition of guide vanes near maintenance rails reduces the maximum amplitude of model displacement by 53.1% whereas the installation of spoilers on handrails eliminates VIVs. The complicated pressure field on the girders surface can be expressed as a linear superposition of aerodynamic forces related to multiple spatial-temporal distribution modes induced by different excitation sources. The pressure on the original girder is dominated by the 1st order SPOD mode where the component at the fundamental frequency of bridge girder is the main ingredient. Meanwhile，the spatial-temporal distribution mode of aerodynamic force on the upper surface contribute more to the VIVs. The predominant aerodynamic forces mode distributing harmonic on the upper surface travels downstream，with the contribution value presenting a wave-like distribution，collectively referring to as the “aerodynamic wave effect”. The aerodynamic wave intensity acting on the upper surface is much greater than that of the lower surface. The propagation of the aerodynamic wave could be characterized by the monotonously decreasing phase lag between the distributed aerodynamic forces and the vortex-excited forces （VEFs）. The wavelength of the aerodynamic wave on the original girder is approximately consistent with the wavelength of the contribution value，which corresponds to the distance between the windward and leeward crash barriers. With the addition of guide vanes near maintenance rails，the predominant mode of aerodynamic wave on the upper surface is similar with that on the original girder while the wave intensity decreases，resulting in a reduction of VIV response. The spatial-temporal energy spectrum of aerodynamic force on the upper surface turns into a broadband distribution after the installation of spoilers on handrails，and the frequency lock-in phenomenon disappeared. Thus，VIVs were eliminated. This study provides a new perspective for the analysis of pressure field on girder surface and constructing mathematical models of the vortex-excited force on bridge girders，which could deeply reveal the mechanism of VIV.

Based on the flow simulations through delayed detached-eddy simulation model，the methods of sparsity-promoting dynamic mode decomposition and spectral proper orthogonal decomposition are applied for analysing the mode decomposition on the wake flow. Then combined by the acoustic analogy approach，this study investigates the behaviour of flow and aerodynamic noise generated around tandem seal-vibrissa-shaped cylinder in comparison with the cases of tandem cylinderlike and elliptical bars with the same characteristic length corresponding to the cylinder diameter of 30 mm for a range of Reynolds numbers （Re=6×10⁴~1.2×10⁵）. Results show that the lift fluctuations of the downstream bars are stronger than those of the upstream bars and the downstream bars dominate the aerodynamic noise radiation. The alternative arrangement of the saddle and nodal planes of seal-vibrissa-shaped cylinder introduces three-dimensional flow separations and suppresses the shear layer interactions，improving greatly the flow stability. The structure destroys the regular vortex shedding of Karman vortex street occurring in tandem cylinder wake. The presence of reverse vortex shedding generated by two adjacent saddle surfaces in the flow of tandem seal-vibrissa-shaped cylinder makes the lateral force balanced partially and reduces significantly the lift fluctuations as well as the vortex-induced vibration. The aerodynamic noise generated by the non-constant fluctuating force exerted on the wall surfaces of bars are suppressed effectively. The sound pressure level is reduced at most frequencies. Thereby the tandem seal-vibrissa-shaped cylinder is demonstrated to have a significant noise reduction effect. The experimental measurements verify the accuracy of the aerodynamic noise predictions. The current work would provide a certain scientific research and engineering application value for the aerodynamic noise control on cylinderlike bars.

To study the influence of different degrees of steel corrosion and axial compression ratio on the seismic performance of corroded L-shaped reinforced concrete （RC） shear walls，the test specimens of 5 L-shaped RC shear walls with a shear-to-span ratio of 2.5 were subjected to accelerated corrosion by using dry-wet cycle and external current corrosion method，then the specimens were subjected to a pseudo-static test. The test results show that with the increase of corrosion degree，the bearing capacity of the specimens gradually decreased，and the decrease rate of positive （flange tension） bearing capacity was higher than that of the negative （flange compression）. The specimen deformation and energy dissipation capacity deteriorated to varying degrees，the stiffness degradation aggravated，and the percentage of shear deformation in the positive peak point increased. When the degree of corrosion was equal，with the increase of the axial compression ratio，the positive failure mode of the corroded specimen developed into small eccentric failure progressively. In the meantime，the positive bearing capacity of the specimens first increased and then decreased，while the negative bearing capacity of the test specimens gradually increased，and the increase rate of the negative bearing capacity was greater than that of the positive； the deformation capacity of the specimens constantly decreased，and the decrease rate of the positive deformation capacity was greater than that of the negative； the energy dissipation capacity，shear deformation and percentage of shear deformation of the specimens all decreased continuously.

A magnetorheological elastomer （MRE） vibration absorber is designed to suppress the vibration of industrial robotic milling in order to solve the low frequency chatter problem. The magnetorheological effect of MRE with different mass ratio is studied by using the unique rheological characteristics of MRE. The number of turns of coil and the current in the absorber are determined by theoretical calculation and numerical simulation. It is found that the designed MRE absorber has frequency shift characteristics in the range of 17.35~45.21 Hz through modal simulation and shaking table sweeping excitation experiment. The mapping relationship between natural frequency of absorber and current is established，which is verified by experiments in the milling process of KUKA KR500 robot. The results show that the robot is prone to chatter at its low order natural frequency under low rotational speed machining conditions，and the chatter suppression of the robot is realized by MRE absorber. Compared with the condition without vibration absorber，the peak-to-peak value of the vibration acceleration in the X direction of the robot spindle is reduced by 70.7%，and the root-mean-square value is reduced by 64.7% after being electrified. The peak-to-peak value in the Y direction is decreased by 54.7%，and the root-mean-square value is decreased by 49.9%. In addition，the machining surface quality of workpieces after milling has also been significantly improved.