A novel method for nonlinear force reconstruction has been developed to reproduce the stick-slip friction contact behaviors of joint interface. Nonlinear substructure modeling is employed to simplify the complex jointed structures into the linear substructures and nonlinear joints. An inversion technique has been developed to eliminate the singularity of transfer matrix，extracting only the transfer relationship between the degree-of-freedoms of nonlinear joints and measuring locations. The harmonic balance method is used to directly apply the measured nonlinear dynamic responses of the linear substructures to reconstruct local hysteresis nonlinear contact forces of the bolted joint interface. Numerical simulations and experimental investigations of a lap-type bolted joint beam system have been performed to verify the nonlinear force reconstruction process，and to investigate the effects of stick-slip friction contact at the bolted joint interface. The good agreement between the comparison results validates the proposed nonlinear force reconstruction method，and the reconstructed nonlinear virtual excitation can be further used to detect the loss of bolt preload effectively.

Complex multi-mode signals can be decomposed into single mode components using time-frequency decomposition technology. This allows for the use of a simple and reliable single mode identification method to identify the complex modal signals of mechanical structure. Empirical wavelet transform (EWT) method can effectively decompose the modes, and some revised methods even can overcome the strong noise. However, when reconstructing the modes, the reconstructed mode could be distorted due to overlapping filters and closely spaced components. Focusing on the problem of mode decomposition and reconstruction, this paper analyzes the problem of distorted reconstructed mode of EWT method, proposes a revised method based on the Iterative Truncated Singular Value Decomposition (ITSVD) method, and applies this new method to both the synthesis signal and the experimental signal from the vibration response of a mechanical structure model with a joint surface. The results suggest that the proposed ITSVD-EWT method is more effective in mode decompose and reconstruction.

At present，traditional Braille books have had difficulty meeting the needs of the blind，this paper proposes a new type of ultrasonic resonant Braille display cell based on the squeeze film generated by ultrasonic vibration. The Reynolds equation which determines the aerodynamic characteristics of the squeeze film is derived theoretically，the mechanical model and approximate solution of the output buoyancy are obtained by using the “piston effect” of the squeeze film，the vibration characteristics and output performance test of Braille display cell were tested using the built experimental platform. The results show that the resonant frequency of the Braille display cell is 30.8 kHz，when the peak-to-peak value of the excitation voltage is 130 Vpp to 200 Vpp，a stable squeeze film with certain buoyancy can be formed. The theoretical calculation results are basically consistent with the experimental results. In the experiment，three kinds of samples can be lifted from 13.92 μm to 47.71 μm，Braille display cell has sufficient output performance.

This paper introduces a method of structural modal parameter identification based on visual vibrometry. For continuous and long time sampling video，this method ensures the accuracy and resolution of measurement results by setting local “virtual” measurement points and enlarging video slices，and significantly improves the data processing efficiency. It includes several steps： recording a video of the test structure under external excitations； Setting a series of “virtual measurement points” at the edge of the structure by using edge detection algorithm； Extracting apparent motions of “virtual measuring points” using optical flow methods，and then identifying natural frequencies and modal damping ratios using the stochastic subspace method； Estimating the full-field operational mode shapes of the structure by applying motion magnification to cropped videos. Two real-life tests are conducted to validate the procedure： firstly，vibration test of a model aircraft excited by a single sinusoidal input is used，where the response peak appears in the same frequency with the known-input. Secondly，operational modal analysis of a cantilevered beam is conducted using visual vibrometry，in which the first five modal parameters are estimated and compared to the measurement results using a Scanning Laser Doppler Vibrometer. It is shown that the maximum relative discrepancies of the natural frequencies and damping ratios are only 0.35% and 14.6%，respectively，and the modal shapes are also observed in excellent correlation.

Recursive Least Squares algorithm is widely adopted in the field of micro-vibration adaptive control because of its simplicity and speed. Due to the particularity and complexity of the disturbance environment in the micro-vibration active control application，the robustness of the parameter adaptive algorithm used in the micro-vibration control needs to be considered. For the Multiple-Input Multiple-Output （MIMO） active vibration control system，this paper presents a MIMO robust parameter adaptive algorithm based on an Infinite Impulse Response （IIR） filter. This robust parameter adaptive algorithm takes advantage of the dead zone and normalization. The deducing process and convergence analysis of the robust parameter adaptive algorithm are illustrated in detail. A 3-DOF real time micro-vibration control experimental platform has been constructed. Comparison are provided with sine disturbance，double sine disturbance and broadband disturbance. Experimental results confirm the feasibility and robust of the proposed algorithm.

Reaction wheels are not only important attitude control actuators for satellites，but also the most prominent onboard micro-vibration source. Considering the varying rotating speed of reaction wheels，this paper proposes a new vibration isolation method using a six-strut isolator combined with the electromagnetic shunt damping （EMSD） technique. A dynamic model of the coupled system consists of a reaction wheel and the isolator is derived including the gyroscopic effect produced by the rotating wheel. The results obtained through analytical analysis and simulations show that gyroscopic effects have a great effect on the natural modes，frequencies，and isolation performance. And then，the influences of key parameters on the isolation performance are analyzed and optimized. Finally，an isolation strut based on the EMSD technique is manufactured and tested. The experiment results verified the influences of the stiffness and EMSD on the transmissibility of the strut.

In this paper，the analytical model of the vibration characteristics for the composite double-layer spherical shell and annular plate coupled structure under different boundary conditions is constructed using the spectral geometry method based on the first-order shear deformation theory，and the boundary conditions of the coupled structure are simulated by the artificial virtual spring technique. The coupling relationship between the sub-structures is simulated by arranging the coupling spring simulator according to the connection relationship. The Hamiltonian principle is applied to derive the characteristic equations of the composite double-layer spherical shell and annular plate coupled structure，and the inherent characteristics and steady-state response of the coupled structure are solved. The results obtained are compared with the results of finite element method to verify the correctness of the calculations. The effects of geometric parameters，material parameters on the vibration response of the composite double-layer spherical shell and annular plate coupled structure are analyzed.

Recursive Least Squares algorithm is widely adopted in the field of micro-vibration adaptive control because of its simplicity and speed. Due to the particularity and complexity of the disturbance environment in the micro-vibration active control application，the robustness of the parameter adaptive algorithm used in the micro-vibration control needs to be considered. For the Multiple-Input Multiple-Output （MIMO） active vibration control system，this paper presents a MIMO robust parameter adaptive algorithm based on an Infinite Impulse Response （IIR） filter. This robust parameter adaptive algorithm takes advantage of the dead zone and normalization. The deducing process and convergence analysis of the robust parameter adaptive algorithm are illustrated in detail. A 3-DOF real time micro-vibration control experimental platform has been constructed. Comparison are provided with sine disturbance，double sine disturbance and broadband disturbance. Experimental results confirm the feasibility and robust of the proposed algorithm.

It focused on the test and simulation study on the longitudinal load transfer law under the coupling shock condition of a roadrailer. The bogie of this type of the vehicle contains the towing plate and the yaw damper device，which are oriented in the longitudinal direction. Therefore the load transmission path and its value need to be investigated for further strength evaluation of the structural component. In the test，force sensors were installed on the key components. In the simulation，a comprehensive whole vehicle dynamic model，which contains 3 carbodies and 4 bogies，was established based on the theory and method of the rail vehicle and multibody dynamics. Meanwhile the collider is simplified to a mass considering its mass and speed to simulate the locomotive. Besides，it gave the modeling details of the yaw damper device and the towing plate. By the SIMPACK solver，the results demonstrate that the forces on the hook and the yaw damper device both increase with the impact speed increasing. Furthermore，the simulation results were slightly smaller than the test results，but the law is nearly the same. Under these conditions，the yaw damper had no effect. Therefore，the transmission path is only through the towing plate，which is useful for further strength evaluation.

Medium and small span bridges make up a large proportion of highway bridges in China. Due to harsh service conditions，the expansion joints are prone to diseases，which can exacerbate vehicle vibrations，and subsequently lead to the damage of the end bearings and other components. In order to study the influence of expansion joint and bearing parameters on the vehicle-induced dynamic response of simply supported beam bridge，this paper establishes a numerical analysis method of vehicle-expansion joint-bridge coupling dynamic response （VBCV-J）. The effectiveness of VBCV-J analysis method is verified using measured data，followed by an investigation the influence of expansion joint and support parameters. The results show that： The speed is closely related to vehicle vibration. When the vehicle speed is high and the Road Surface Condition （RSC） is “normal”，the impact effect of vehicles on expansion joints and the ends of beams can exceed the specified values.. If the girder in the expansion joint is higher than the pavement，the impact on the expansion joint will significantly increase，conversely，it will decrease. When the girder in the expansion joint is higher or lower than the road surface，the impact at the end of the main beam will increase. A reduction in the support stiffness of the expansion joint or a void in the side support of the main beam will significantly increase the impact effect on both the expansion joint and the end of the main beam. A decrease in the stiffness of the main beam support primarily results in an increased impact on the entire main beam. Damage to the expansion joints not only affects their own impact，but also greatly increases the impact on the end members of the simply supported beams. During design and maintenance，sufficient attention should be given to the end members of the beams.