In order to apply active dry friction dampers （DFD） to the vibration control of rotor system，a model free adaptive force control scheme is proposed，where virtual feedback tuning method is exploited to tune the initial parameters. Vibration characteristics of the active DFD-rotor system are analyzed based on a two-dimensional dry friction dynamic model. And vibration control strategies are proposed to match the response characteristics of rotors. Then，a compact-form dynamic linearization model is applied to design model free adaptive control algorithm. Meanwhile，considering the cumbersome work of initial parameter tuning，a virtual reference feedback tuning procedure is used to initialize parameters for the controller and the rules to choose parameters used for off-line data generation is also discussed herein. In order to verify the efficacy of the proposed algorithm，a rotor system containing two discs is taken as the numerical example. Results reveal that，based on one single off-line parameter tuning procedure，the rotor vibration when critical speed is traversed can be efficiently controlled by the proposed control strategy. Meanwhile，for steady vibration control，the proposed strategy is able to adaptively apply controllable forces only if the vibration level is too large，in which case the unbalanced responses of rotors can be sustained within allowable range.

The seismic dynamic response of pile foundation in inclined liquefaction site is an important issue in the field of geotechnical seismic engineering. Based on the shaking table model test carried out by our research group and the OpenSees software platform，a two-dimensional integrated numerical model of inclined liquefied soil-pile group-structure interaction is established in this paper. The nonlinearity of pile-soil contact and the shear localization of soil layer are considered in the model. The rationality and effectiveness of the numerical simulation method are verified by comparing with the shaking table test results. On this basis，a typical inclined liquefied site-pile group-structure interaction finite element model is established to discuss the influence of different overlying crust on the seismic response of site and structure system. The calculation results show that with the increase of the thickness of overlying crust，the pore pressure ratio in the saturated sand decreases，the horizontal residual displacement of soil decreases，and the displacement of pile body and the pile curvature decrease. The effect of the strength of overlying crust on the dynamic response of pile foundation is more obvious. The increase of the thickness of overlying crust can reduce the liquefaction degree of sand and improve the mechanical performance of pile foundation.

In the processing of near-fault original seismic acceleration records，how to retain the real ground permanent displacement information is a key problem to be solved in the baseline correction of seismic acceleration records. Based on the analysis and discussion of the validity and applicable scope of existing near-fault seismic acceleration baseline correction methods，this study introduces a smooth slope displacement function model and establishes a new baseline correction method that can reasonably characterize the permanent displacement of near-fault ground motions，and the new baseline correction method is verified by analyzing the baseline correction results of typical near-fault acceleration records. The results show that the new method established in this study improves the fitting accuracy between the displacement function model and displacement time history，reduces the influence of the selection of subjective parameters on the baseline correction results，and the corrected ground permanent displacement is in good agreement with the GPS co-seismic displacement. The ground motion baseline correction method established in this paper can not only automatically deal with the baseline drift of near-fault ground motion，but also reasonably characterize the permanent ground displacement caused by fling-step effect.

A practical analysis method for inertia damper energy dissipation systems composed of building structures with inertia dampers is proposed，including of concise closed-form solutions for the random seismic response and a practical setting strategy for inertia dampers. Based on the mechanical structure diagram of the series inertial damper and installation method in buildings，the coupled seismic motion equation of the energy dissipation system is established. In response to the difficulty in solving the damping and stiffness parameters in the actual dynamic equations of structures，an equivalent form of the uncontrolled structure represented by real modal vibration parameters is obtained based on finite element technology and dynamic principles，and the dynamic equation of the inertia damper energy dissipation system is reconstructed. Based on the quadratic decomposition method of the power spectral density function，closed-form solutions of the spectral moments of the building structure relative to ground displacement，interlayer displacement，and inertial damping force are derived. The correctness of the proposed concise closed form solution is verified through numerical examples，and the influence of real mode number on the 0~2 spectral moment of series response and the influence of floor position of inertia dampers on the seismic reduction effect of structures are studied. Results show that，using the number of actual vibration modes corresponding to the cumulative participation coefficient of 100% in the free vibration analysis of uncontrolled structures can achieve stable analysis accuracy and computational efficiency for the response analysis of multi-degree of-freedom energy dissipating structures，and to use reducing interlayer displacement of uncontrolled structures as the placement strategy for installation of inertial dampers is simple and feasible. This paper can provide a reference for the analysis of random ground motion response of complex building structure with series inertia capacity system.

Based on the porous medium theory and the continuum medium fluctuation theory，this paper studies the amplitude reflection and energy reflection properties of the plane P₁ wave reflection on the unsaturated semi-space free boundary. Using Helmholtz decomposition theorem and specific free boundary conditions，the analytical expressions of the amplitude reflection coefficient and energy reflection coefficient of four types of reflected waves （reflection P₁ wave，reflection P₂ wave，reflection P₃ wave，and reflection S wave） generated by the plane P₁ wave are obtained，and the effects of incidence and saturation，frequency and porosity on energetic properties is analyzed. The results show that the amplitude reflection coefficient and energy reflection coefficient not only are affected by the angle of incidence，but also have significantly changed with the change of saturation，and the reflected P₁ wave and reflected S wave carry the vast majority of the incident wave energy.

In order to improve the energy absorption and safety of the energy absorption hydraulic support，a multi-layer lattice energy absorption device is designed. The basic structure of pyramid lattice energy absorption device is designed according to the structure and energy absorption space of energy absorption support column. The maximum energy absorption of the energy absorption device，the maximum mean of the support force within the allowable range，and the minimum fluctuation coefficient of the support force are taken as the optimization objective function，the base diameter and span of the pyramid cell are taken as the optimization design variables，and the constraint conditions are taken as the peak and mean of the support force of the energy absorption device within the allowable range. The Workbench software is used to optimize the structural parameters of the energy absorption device with the pyramid height of 30 mm，40 mm and 50 mm respectively. Three groups of optimization solutions are obtained and the optimal structural parameters are determined by comparative analysis. The single-layer energy absorption device with the optimal parameters reduced in the compression experiment was used for experimental analysis，and the results show that the absorption energy is 4.18716 kJ. The calculated energy absorption energy of the original single-layer energy absorption device is 113.05332 kJ，and the energy absorption energy of the whole energy absorption device is 565.2666 kJ. The relative error between the experimental results and the simulation results is only -9.92%. The energy absorption capacity of the new energy absorption device is at least 50% higher than that of the traditional thin-wall structure energy absorption device，which proves the effectiveness of the optimized design and the high energy absorption capacity of the energy absorption device.

To achieve rapid recovery of structural function after the earthquake，based on the idea of replaceability and additional energy consumption，a new earthquake-resilient fully bolted beam-column joint is introduced in this study. The shortcoming of insufficient energy dissipation ability of the existing fully bolted joint loaded into large deformation condition is improved by setting up the T-shaped energy dissipator. The influence of the energy consumption length and slenderness ratio of the T-shaped energy dissipator on the seismic behavior of the new earthquake-resilient fully bolted joint is studied. Three new earthquake-resilient fully bolted joints and one welded joint were subjected to low-cycle loading. The results of tests show that the seismic performance of the new earthquake-resilient fully-bolted joint is better than that of the traditional welded joint. The new earthquake-resilient fully-bolted joint can concentrate the plasticity and damage，transfer the plastic zone to the T-type energy dissipation plate，and avoid the fracture of the welding zone at the beam end. In this paper，the lower limit of the length of the energy dissipation segment is given. When the energy dissipation segment has sufficient deformation length，and the cross-section area of the energy dissipation section is the same，the conservative slenderness ratio is determined to be 13.2，which can make the new joints have good bearing capacity and ductility，and give full play to the seismic performance of the new joint.

To address the issue of carrying rolling element bearing （REB） fault diagnosis where the conventional vibration sensor is difficult to install，an instantaneous angular speed （IAS） signal based REB fault diagnosis method by optimized AR model is proposed. The forward differential method is used to calculate and estimate the instantaneous angular speed signal. Then，the biased estimation autocorrelation analysis is used to determine the optimal order p by the maximum autocorrelation kurtosis. Periodic components in the IAS signal are removed by AR prediction，and the residual components containing rich bearing fault information are remained. The residual components are pre-whitened to equalize the importance of each band and to extract fault characteristics from the envelope. Simulation signal and outer ring data from a test rig validate the effectiveness of the proposed method. The experimental comparative analysis results show that the calculation efficiency is improved significantly when compared to the existing method of fast spectral steepness combined with order analysis based on vibration signal.

A vibration-controlled device with paired inclined nozzles is designed to reduce the barrel vibration and minimize the impact on the aircraft during continuous firing. The newly designed paired inclined nozzles generate only dynamic moment and recoil force，without producing transverse force. An interior ballistics model of the barrel with lateral channels is established，and the TVD-MacCormack difference scheme is utilized to numerically calculate the flow field in the barrel and the time-dependent aerodynamic force of the nozzles. Dynamic simulations of the continuous firing process of the aircraft gun are conducted to evaluate the effect of the paired inclined nozzles on the muzzle vibration. Results show that the time difference of the maximum aerodynamic force of the two nozzles is 0.07 ms，with a relative difference of the maximum aerodynamic force of only 0.5%. This indicates that the two nozzles are well synchronized. The paired oblique nozzles can greatly reduce the muzzle vibration without compromising the initial velocity of the projectile. The linear displacement and velocity of the lateral vibration decrease by 26.9% and 44.3%，respectively. The recoil momentum also decreases by 17.93%，without generating transverse force on the aircraft. As a result，the impact on the aircraft is significantly reduced. The achievements of this research will support the design of aircraft gun barrels with paired inclined nozzles.

Aiming at the robustness and stability of the vibration active control of motor-driven seawater pumps，a hybrid structure adaptive vibration active control strategy is proposed based on the Kalman filter （KF） algorithm，which establishes the system state prediction equations，state transfer matrix and measurement matrix，and builds a hybrid structure adaptive vibration active control system model. In order to improve the convergence performance of the algorithm，an online update strategy for the measurement noise covariance matrix is proposed. Simulation results show that the new control strategy effectively overcomes the strong correlation between the reference signal and the vibration source based on the classical Filtered x Least Mean Square algorithm （“FxLMS”），and realizes effective vibration active control under the premise that Gaussian white noise is used as the reference signal. The robustness，stability，and control effect of the proposed strategy are all superior to that of the FxLMS algorithm with a variable step size. The results provide theoretical support for engineering practice and have certain potential application value.