In order to study the influence of partially isolation on the dynamic characteristics and seismic performance，taking a dominate large terminal airport as a research object，a 3 dimensional finite element model using ABAQUS software is established. Based on this model，the structural vertical vibration modes，the effective mode mass，the vertical vibration acceleration，vertical deformation，component ductility，plastic damage and residual deformation are analyzed to reveal the influence of partially isolation on the dynamic characteristics and seismic performance. It’s demonstrated that partial isolation changes the vibration modes，increases the effective mode mass and magnify the vertical seismic load of the terminal building. At the same time，partial isolation filters the high frequency vibration，enlarges the low frequency vibration near the isolation frequency and increases the vertical acceleration and deformation. The plastic damage and residual deformation has been concentrated on the middle and end sections of innerspan beams.

A spectral geometry-incremental harmonic balance method（SGM-IHBM）is proposed to study the nonlinear vibration characteristics of functionally graded porous（FGP）beams with geometric nonlinearities. The geometrically nonlinear strain-displacement relationship of the beam structure is obtained according to the Von-Karman theory，and the Lagrange energy function of the FGP beam is derived based on the Timoshenko theory. The spectral geometric series are used to characterize each displacement component of the beam structure，and the linear modal components are introduced to establish the nonlinear reduced-order equations of the FGP beams，and then the incremental harmonic balance（IHB）method is used to trace the dynamical response solution of the reduced-order model of the FGP beams. The correctness of the nonlinear model in this paper is verified by comparing the SGM-IHBM solution with the literature solution，and then the effects of porosity，thickness，and excitation amplitude on the nonlinear vibration characteristics of FGP beams are analyzed.

The dynamic behavior of the Duffing-van der Pol oscillator with fractional-order derivative and parametric excitation is studied in this paper. The effects of various parameters on the amplitude-frequency curves of the system under the combined action of viscous inertia（1≤p≤2）and parametric excitation are analyzed. The system is analyzed by the averaging method，and the fractional-order derivative is treated by the concepts of equivalent linear damping and equivalent mass. The approximate analytical solution of the system is obtained and compared with the numerical solution. The curves of the two solutions agree well with each other to a large extent，which proves the correctness of the analytical solution. The influences of system parameters on the amplitude-frequency curve are analyzed. It is found that the resonance peak value，resonance frequency，resonance region，the range and the number of multivalued solutions are all affected by the system parameters. Through analysis，it is found that the external excitation amplitude and the coefficient of fractional-order derivative can suppress the effect of parametric excitation to some extent.

To establish the optimal design method of multiple tuned mass damper（MTMD）for the footbridge considering the vertical human-structure interaction，the parameters randomness of the mass-spring-damper（MSD）pedestrian model is simulated，and the vertical dynamic response of the random crowd-footbridge-MTMD system is calculated based on the pseudo-excitation method. Then，the effect of vertical human-structure interaction on the dynamic response of the footbridge-TMD system is demonstrated. Finally，based on the H₂ performance of the acceleration transfer function and response surface methodology of the coupled system，an optimal design method of MTMD for footbridge vibration control considering vertical human-structure interaction is established. The results show that the dynamic response calculation method of the coupled system avoids a large number of nonlinear time history analyses，and the power spectrum and root mean square of the coupled system response can be obtained efficiently. The vertical human-structure interaction makes the TMD detuning effect significant，and the reduction rate of TMD with 3% mass ratio decreases by 37.19% when the crowd density increases from 0.25 person/m² to 1.25 person/m². The proposed MTMD optimization design method for footbridge has an average mitigation rate of over 70% for footbridge acceleration response.

To reduce the starting isolation frequency of the isolator，enhance adaptability to different vibration sources，and achieve superior vibration suppression effects compared to traditional passive isolators，this study proposes a high static-low dynamic stiffness（HSLDS）isolator with asymmetric stiffness structure employing electromagnetic coils nested with permanent magnets. It can adjust the system stiffness according to changes in vibration source frequency，thereby realizing semi-active vibration isolation. The incremental harmonic balance method is employed to obtain the displacement transmissibility characteristics of the system under different excitations and currents. Based on the system model of the isolator，a semi-active control strategy is proposed in this study，which can adjust the system stiffness according to changes in vibration source frequency. An experimental test platform was constructed for experimental research. The results show that the proposed HSLDS isolator can reduce the starting isolation frequency by 19.25%. Introducing the semi-active control strategy can attenuate the maximum acceleration amplitude by 54.7%.

The influence line is an important parameter of the elastic mechanical state of the bridge structure，which can effectively reflect the resistance and deformation resistance of the structure，and is expected to be used to evaluate and predict the elastic-plastic response during earthquakes. Taking the influence line of a three-span steel plate composite continuous beam bridge as the model correction target，the bridge model correction research is carried out based on BP neural network. With the expectation of Beta distribution as the earthquake damage index，the overtaking probability expression of the bridge model under various performance levels is fitted，and the seismic vulnerability of the continuous beam bridge structure before and after the finite element modification is analyzed and compared. The results show that the relative error between the measured value and the calculated value can be reduced from 38% to less than 10%，and the earthquake damage index of the modified finite element model is lower than that of the initial model. By incorporating the Beta distribution to weight and integrate different performance levels，the structural vulnerability matrix can be transformed into a seismic damage index，thereby accounting for the damage consequences of different failure levels and providing a more comprehensive representation of the seismic performance of the bridge structure.

To improve the whole seismic performance of the frame structure，especially the beam-column joint，a new seismic reinforcement method is proposed for reinforced concrete frame structure with adding a web-type plate. The internal force optimum can be achieved by setting the web-type plate at a certain region between frame beams，and the bending moment of the beam-column joint will decrease. A multiple seismic defense lines frame structure can be formed with the web-type plate. A typical frame structure of 10 stories is designed as a case study. The effects of the layout，linear stiffness ratio，and reinforcement of the web-type plate on the structural performance are analyzed. The reinforcement ratio of the web-type plate to the column and beam is proposed. The seismic analysis shows that the lateral stiffness of the structure is improved，meanwhile the bending moment of the beam-column joint is reduced. The optimum layout position of the web-type plate is 0.3 and 0.7 of the beam span，and the suggested linear stiffness ratio of the web-type plate to column and beam are 0.7~1.5 and 3.5~7，respectively. Further，a suggested reinforcement ratio of the web-type plate is given by nonlinear parametric analysis to ensure that the plate yields first as designed. The nonlinear dynamic time-history analysis of an actual engineering project that seismic upgrading with the web-type plate is undertaken. The analysis results show that the lateral displacement，and the inter-story drift ratio of the structure with web-type plate are reduced. Compared with the structure before upgrading，the plastic hinges are reduced. The seismic performance of the frame structure reinforced with the web-type plate is improved. The analysis verify that the proposed strengthening method with web-type plate was reasonable and feasible.

In order to accurately study the nonlinear dynamic characteristics of NW（internal and external meshing planetary gear train）wind power transmission system，this paper considers factors such as random wind speed，time-varying support stiffness，ring gear flexibility，time-varying meshing stiffness，transmission error，tooth flank clearance，and bearing clearance. A nonlinear dynamic model of the NW planetary gear-bearing system is established. Time history，FFT spectrum，Phase diagram，and Poincaré maps are used to describe the nonlinear characteristics of the system，and bifurcation diagrams and the maximum Lyapunov exponent are used to describe the influence of excitation frequency and meshing stiffness on the nonlinear behavior of the system in more detail. The results show that the NW planetary gear-bearing system has rich nonlinear characteristics. In a specific range of excitation frequencies，the system can enter a chaotic motion state，leading to instability. However，within a certain range of meshing stiffness，the system can operate stably.

The bushing element is established for dynamic modeling of rolling linear guideway joints based on the movement characteristics of guideway. The effectiveness of the bushing element is verified by the numerical and experimental examples. Base on the fact that the guideway joint has significant influence on the dynamic performance of the whole structure，the model updating technique combined with the substructure method is proposed for parameter identification of bushing element. A simulation example of dumbbell structure is used to verify the effectiveness of the proposed parameter identification method. Based on the simulation example，a dumbbell structure with single slider rolling guideway is used for bushing element parameter identification and model verification. The effectiveness and universality of the bushing model is verified by a rolling linear guideway structure which contains four sliders. The engineering application of the bushing element is verified by the structure of rolling linear guideway moving platform of special ring welding machine. The results show that the bushing model is simple for application，the dynamic modeling error for single slider rolling linear guideway is within 5% and the error for four sliders rolling guideway system is within 12%，and the error of engineering structure of moving platform with four sliders is about 11%.

The axle-box bearing is a key component of high-speed trains，and the wheel-rail excitation caused by complex braking conditions leads to extremely complex vibration and contact characteristics of axle-box bearings and it is unclear until now. Therefore，a rigid-flexible coupled dynamics model of a high-speed train considering braking systems and axle-box bearings is established. Moreover，the braking system，axle-box bearing and vehicle system are dynamically coupled via the nonlinear friction of the braking interface，wheel-rail interactions，nonlinear contact of the axle-box bearing and suspension systems. Further，the field tests are conducted to verify the effectiveness of the established model. Based on this，the vibrations，bearing internal force，and contact characteristics of axle-box bearings under different braking conditions are systematically studied. The results indicate that train braking increases the longitudinal force of the axle-box bearings on the first and second wheel-set，and enhances the longitudinal vibration. The vertical vibration of the axle-box is slightly influenced by braking. In addition，when the train brakes，the friction between disc and pad makes the pitch motion for bogie frame，causing changes in the primary suspension force on the first and second wheelset，resulting in a decrease in the vertical force of axle-box bearing on the first wheel-set，an increase in the vertical force of the axle-box bearing on the second wheel-set，and ultimately an increase in the maximum roller-raceway and contact stress of the axlebox bearing on the second wheel-set.