In order to finely and continuously adjust the damping of a spring-suspended sectional model （SSSM） system in the wind tunnel test，a double-sided permanent magnet plate-type eddy current damper （ECD） device is developed in this paper. First，the basic structure of the ECD is introduced and its design points are analyzed. Then，the rationality of the structure for the ECD is analyzed by using the electromagnetic finite element steady-state analysis method，its working range is predicted，and the influence of the motion speed and position offset of the conductor plate on its working performance is analyzed. Finally，the relationship between the vertical and torsional additional damping ratio provided by the ECD to the SSSM system is derived，and the linear characteristics of the eddy current damping and the cooperative adjustment ability of the damper to the vertical and torsional additional damping of the SSSM system are verified by experiments. The study shows that the double-sided permanent magnet plate-type ECD can provide continuously adjustable linear viscous damping for the SSSM system with different scaling ratios，and the damping coefficient is stable and not easily affected by the front-back，left-right and up-down position offsets of the model，which is also suitable for the wind tunnel test of the SSSM system with large bending-torsional coupling vibration. By installing two dampers symmetrically along the diagonal of the SSSM system，the vertical and torsional damping ratios of the SSSM system can be cooperatively adjusted，which provides conditions for the fine study of the bending-torsional coupling wind-induced vibration of the SSSM system.

This article investigates the optimization problem of a novel base isolation system by introducing a passive network consisting of one damper，one spring and one inerter and a grounded element with negative stiffness. The dynamic equations of the system are established and the frequency response function in the dimensionless form is derived. Since it is found that the amplitude-frequency response curves pass through four fixed-points，the extended fixed-point method is utilized to solve the parameter optimization problem. The explicit expressions of the optimal inertance-to-mass ratio，the optimal natural frequency ratio，and the optimal corner frequency ratio of the system are derived by adjusting the four fixed points to the same height. The expression of the optimal damping ratio is calculated by letting the amplitudes of the three invariant frequencies among the four fixed points to the same amplitudes as those of the four fixed-points. A necessary and sufficient condition for the system with optimal parameter values to be stable is derived by utilizing the Hurwitz stability criterion. Compared with other three optimal isolation systems，the optimal isolation system in this article can provide better H_∞ performance and better output responses in the multi-storey building vibration system.

Inerter element is a mechanical element whose inertia force is proportional to the relative acceleration between its terminals. This kind of specific inertia force is not involved in classical theory of Structural Dynamics. From the point of view of inertial and non-inertial reference frame，the inerter element is proposed as a real inertial force element. The difference between the real inertial force of inerter element and the virtual inertial force of classical mass element is also explained. In order to illustrate the differences between inerter-based technology and classical structure control technologies，the vibration mitigation mechanisms of classical technologies are elaborated firstly. Based on the mechanical relationship of inerter element and inerter system，the concepts of inerter element，inerter system and structure with inerter system are defined and explained. From the point of motion equations and energy equations of structures with inerter systems，the enhancement mechanism of inerter-based technology is revealed. The characteristics of inerter-based technology，involving dynamic negative stiffness，lightweight tuning and targeted modal control，are also described，which provides an alternative way for high-performance control of structure. On this basis，the theoretical design framework of inter-story，lightweight-tuned and isolated structures with inerter systems are given，performance-oriented optimal design namely，which can provide reference for the practical design of structure with inerter system.

Due to the lack of research on the dynamical response of the inerter system based on non-stationary seismic excitation，an analytical solution for the time-varying variance of the dynamical response of a multi-degree-of-freedom energy-consuming structure with series-parallel layout Ⅰ inerter system （SPIS-Ⅰ） is proposed. According to the constitutive relationship of the SPIS-Ⅰ，the dynamic equations of the energy dissipation structure，and the impulsive non-stationary seismic excitation，we decouple the inertial energy dissipation structure into first-order systems using complex modal analysis and the virtual excitation method. It is convenient to obtain the unified solution of the structural response quantities such as displacement，velocity，inter-story shear force，etc. The quadratic decomposition method is used to transform the time-varying power spectral density function of the unified solution into a linear combination of the complex modal eigenvalues of the inertial-capacitated energy-consuming structure，the modal coefficients，the time-varying modal strength coefficients，and the quadratic product containing the squared term of the circular frequency. On this basis，an analytical solution for the time-varying variance of the response of the energy-consuming structure under non-stationary seismic excitation is derived by utilizing the characteristics that the non-stationary modes spectral moments have an analytical solution in the infinite integration interval. The accuracy of the proposed dynamic response power spectrum and time-varying variance is verified by using the sudden white noise excitation to analyze the dynamic response of the structure. At the same time，the dynamic response of the frame structure based on the sudden Kanai-Tajimi model is studied，and the influence of the parameters of the inertial system on the damping effect is analyzed. The proposed method can be applied to analyze the seismic response of linear structures under other non-stationary modulation functions.

In this paper，the strong earthquake records of 13 soil stations within 41 km from the fault of the 2008 Wenchuan 8.0 magnitude earthquake are selected. These records are combined with the strong earthquake records of 29 calculation points obtained by using the stochastic finite fault method simulation. Moreover，nonlinear least squares fitting is performed by using three near-fault ground motion attenuation models and the fifth-generation ground motion parameter zoning map attenuation model to obtain the peak ground motion acceleration of the Wenchuan earthquake near-fault. The attenuation relationships are obtained and analyzed by considering ±1 times standard deviation and correlation coefficients for reliability. The results show that there are some differences in the attenuation relations obtained by different attenuation models. The peak acceleration obtained by the Shao Guangbiao model is low. The prediction results of Wang Guoquan model has a large deviation for other magnitude earthquakes because the magnitude term is not considered. Besides，the peak acceleration of the fifth-generation ground motion parameter zoning map attenuation model is low.

Tianjin Metro Line 6 is adjacent to Beiyangyuan Campus of Tianjin University，and the train operation may cause adverse vibration effects on important infrastructures of the campus. In this paper，the National Facility for Earthquake Engineering Simulation of Tianjin University，which is close to the line，is taken as the research object. Firstly，the site vibration test is carried out on the sites distributed along the line and the adjacent constructions，through which the vibration attenuation law along the site and the vibration level of the control points in the constructions are studied. Furthermore，a whole process finite element model of tunneling-site-facility constructions is established，and the vibration simulation analysis of site and facility constructions is carried out considering whether the protected river exists or not （actually there is a protected river）. The vibration isolation efficiency of the protected river is emphatically discussed. The research shows that the vibration impact of the operation of Tianjin Metro Line 6 on the large-scale earthquake engineering simulation research facilities of Tianjin University meets the limit requirements of the code. Affected by Tianjin soft soil and the protected river，the vertical acceleration attenuation of the site is significant，and the attenuation rate reaches 97.33% from 0m to 80 m. The design of the mass concrete foundation of the facility and its bottom pile foundation is helpful to the vibration control of the foundation itself. Due to the presence of protected river，the amplitude of the site and the large shaking table foundations was reduced by 40.87% and 27.97%，and the frequency spectrum of the site showed obvious “double peak” phenomenon in 0~20 Hz and 40~80 Hz bands.

To establish a 3D metro train-FST coupling model in the frequency domain，the key problem of the rail displacement at each moving wheel-rail contact point caused by all moving wheel-rail forces needs to be solved firstly. The matrix of the TFC establishes the relationship between them. Based on the established 3D discrete supported floating slab track model in the frequency domain，a method to calculate the TFC is put forward in this paper. Based on the relationship between the fixed and moving coordinate systems，the TFC to a moving point on FST can be written as the integration of the rail displacement response at a fixed point in the frequency domain caused by a moving harmonic load. After calculating the TFC of the 3D FST，some conclusions are obtained. At each excitation frequency，the TFC of a moving wheel-rail force to each wheel-rail contact point is the largest at the point of the force itself. Due to the moving of the wheel-rail force，there is a certain difference between the TFC of the front axle wheel-rail force to the rear axle wheel-rail contact point and that of the rear axle wheel-rail force to the rear axle wheel-rail contact point. In the same bogie，the TFC of the left wheel-rail force of the front axle to the right wheel-rail contact point of the same axle is similar to the TFC of that force to the left wheel-rail contact point of the rear axle. It is advisable to use a 3D model to finely analyze the dynamic characteristics of floating slab tracks.

Vehicle transport is an important part of logistics transport. It is of great significance to study the response of cargoes in the process of vehicle transport. Considering the coupling effect between cargo and vehicle bottom，an 11-degree-of-freedom vehicle-cargo coupling model is established. The relationship between three-way response is compared，and the influence of different road levels and cargo-related parameters （load，stiffness，damping） on the system response is taken into consideration. The results show that the coupling effect of vehicle-cargo significantly affects the system response. The influence of rotation in transportation cannot be ignored. The vibration response of cargo increases with a decrease of load，stiffness and damping. The worse the road condition is，the bigger the vibration response of cargo and vehicle bottom will be. The research results are of great significance and value for the design of vehicle-cargo transportation system.

Extracting sensitive damage features from structural response signals is crucial for damage identification methods based on pattern classification. To this end，a hybrid network that combines a deep belief networks （DBN） and a long-short term memory （LSTM） network is proposed through a hybrid learning mechanism to utilize the merits of both networks in the aspects of extracting high-order abstract features and considering data sequence correlations. First，transmissibility data from response signals are sequentially input into the DBN to achieve the initial data compression and feature extraction，reducing the redundant information in the responses. Then，the extracted feature sequences are input into the LSTM network to consider the correlation between the different responses for acquiring the relevant sensitive damage features. Finally，a classification layer with the Softmax function is used to classify the features output by the LSTM network. Thereby，different structural damage patterns can be identified. The damage identification results on a three-dimensional experimental steel frame demonstrate that the hybrid learning mechanism can better train the network parameters，and the fine-tuning on the whole hybrid network contributes to the subsequent damage feature classification. Under the pollution of numerical or measured noises，the hybrid network can still effectively perform the data compression，feature extraction and classification. The various damage scenarios of the experimental frame are well identified.

The star-shaped negative Poisson’s ratio structure is used as the core of sandwich panels. The dynamic model of a sandwich plate is established，and the equivalent elastic parameters of sandwich layer are derived. The equations of motion of sandwich plates are derived based on Hertz theory，first order shear deformation theory and Hamilton principle. Then，the equations of motion are solved by navier method. The contact force of the impact model is obtained through the spring-mass model with two degrees of freedom，and the lateral displacement of the sandwich plate after impact is calculated by Duhamel integral. The predicted results of plate contact force and lateral displacement are compared with the published papers to verify the accuracy. Meanwhile，the low-velocity impact response of star-shaped negative Poisson’s ratio sandwich panels is also compared with the negative Poisson’s ratio concave hexagonal honeycomb sandwich panels，and the influence of the parameters of sandwich panels is also discussed. When the impact velocity increases，the maximum contact force and the maximum lateral displacement of the sandwich plate also increase，while the duration of the impact response decreases. The greater the thickness ratio of the sandwich plate is，the better the impact performance of the sandwich plate will be. The smaller the side length ratio of cell is，the better the impact performance of sandwich plate will be. The increase of the cell concave angle enhances the impact performance of the sandwich panel. This study can provide some reference for the study of impact resistance of negative Poisson’s ratio metamaterial structures and sandwich panels.