The band gap characteristics of periodic structures provide a new idea for the field of seismic isolation in civil engineering，among which the one-dimensional periodic foundation structure has garnered significant attention due to its simple structure and economical applicability. In this paper，by studying the vibration characteristics of the one-dimensional periodic base structure，an approximate analytical solution for calculating the one-dimensional rubber-concrete periodic base band gap is derived，and on this basis，a one-dimensional rubber-concrete periodic foundation optimization design method based on the resonance zone of the superstructure is proposed. Numerical examples in the frequency domain and time domain show that the periodic foundation designed by this optimization method can ensure a good damping effect of its superstructure in a wide and continuous frequency range.

The longitudinal linkage of the floating slab track （FST） has weakness due to the dynamic effects of FST longitudinal linkage，which are not adequately considered in the track design. By introducing the method of equivalent density and equivalent foundation coefficient to simplify the model of the base of a steel-spring-FST system，a three-dimensional finite element model of vibration characteristics analysis of prefabricated short and cast-in-situ FST system is established. In the proposed model，the influence of the rail，shear hinge，and foundation under the slab on the vibration characteristics of the floating slab structure is fully considered. The modal analysis and harmonic response analysis are analyzed with a focus on the dynamic effect characteristics of the longitudinal connecting slab of the FST system. The results show that： The modal shape of the FST in the low frequency band of 1~200 Hz mainly shows four types of motion： rigid body motion，bending，bending-torsion combination and torsion； For the prefabricated slab track system，the frequency band in which the floating slab dominates the vibration characteristics of the system conforms the system modal analysis and harmonious response analysis； For the cast-in-situ slab track system，when the frequency is within 32.6~57.8 Hz，the frequency band is the transition band，where the dominant role of the FST in the vibration characteristics of the system is weakened； The lower-order bending modes generated by the coupled slab dynamic effect are expressed as rigid body motion modes in the prefabricated slab system； for the FST composed of N_s slabs，the number of additional modes around each order of bending mode frequency of a single slab caused by the coupled slab effect is N_s/2‒1.

In the process of maneuvering flight，the aeroengine will bear very harsh working conditions，leading to irregular transient vibrations that can result in failure. In this paper，the effect of a semi-active magnetorheological damper （MR damper） on the dynamic characteristics of a rotor system under maneuvering flight is investigated. The finite element model of the rotor system with MR damper under maneuvering flight is established using the finite element method. The Newmark-β numerical method is used to solve the dynamic equations，and the dynamic characteristics of the rotor system during maneuvering flight are studied. On this basis，considering the effects of MR damper on the transient，the steady state responses of the rotor system under maneuvering flight are analyzed. The results show that transient impact is caused at the beginning and the end of maneuvering flight，which stimulates the first order modal response of the rotor system. The MR damper with suitable current can effectively suppress the amplitudes of transient and steady-state responses of the rotor system during maneuvering flight. In addition，due to the large eccentricity of the journal in maneuvering flight，the MR damper is prone to produce nonlinearity.

There is a lack of detection means for the isolation performance of the buildings built by passive control technology，so it is of great significance to test the dynamic characteristics of the isolated structures on the spot. A 4-story base isolation kindergarten was tested in the field，and the test device，method and results were displayed. The results were compared with the seismic structure model under the same conditions，and the dynamic response law and damping effect of the actual isolation structure were explored. The building was pushed away with hydraulic jack to produce 98 mm （corresponding to LNR500 shear strain 102%） horizontal initial displacement of the isolation layer，and concrete jacking rod was installed to support the building； The concrete rod was blasted with explosives and unloaded instantly to make the building vibrate freely； The dynamic response and other parameters were tested and analyzed. The results show that under the condition of horizontal initial displacement，the first-order natural vibration period of the isolated structure is significantly longer than that of the seismic structure，and the damping ratio increases； The hysteretic curve of the isolation layer is full； The dynamic response control effect of each floor is obvious，but the acceleration of the roof floor is slightly amplified compared with that of the bottom floor； After unloading，the isolation layer instantly resets，which shows that the isolation layer has rapid reset performance.

In order to give full play to the seismic potential of the movable support pier and improve the overall longitudinal synergistic effect of the continuous girder bridge，based on the principle of functional separation and synergistic force，a new type of mass rotation wrap rope device is proposed based on the mechanism of wrap rope. Taking a typical three-span continuous girder bridge as an example，the shaking table test is carried out by inputting actual seismic waves with different seismic spectrum characteristics and intensity as excitation，the seismic response with equal pier height model and unequal pier height model are analyzed to explore the synergistic force and shock absorption effect of the device on the continuous girder bridge. Through the test results of the response of the key positions of the structure such as the acceleration response，displacement response and strain response，it can be seen that the effect of the device on the movable bearing pier participating in the overall longitudinal synergistic force of the continuous girder bridge is more obvious，and with the increase of the ground motion input intensity，the synergistic effect of the device becomes more and more prominent，the design intention of the device is realized. At the same time，the effect of the device is related to factors such as the number of wrap rope turns of the device itself，the pier height of the movable bearing pier，etc. The design needs to determine the reasonable design parameters of the device according to different factors such as the pier height to achieve the best effect of the device.

The shortcomings of fault diagnosis methods based on deep convolutional neural networks is that，tensor data is easily destroyed when reducing the dimension of high-order input tensors by pooling layers，which results in a loss of data information，and the relatively complex network structure. Therefore，a Deep TensorProjection Networks method is constructed via replacing the pooling layer in the traditional CNN by a TensorProjection Layer. The TensorProjection Layer reduces the dimensionality of input high-order tensor data without causing damage to the data，thus avoiding the impact of the loss of feature information，and greatly improving the recognition accuracy of the model. The dimensionality of the TensorProjection Layer used for dimensionality reduction is variable，thus simplifying the networks structures. Based on this，combined with the respective advantages of high-order spectrum and deep TensorProjection networks，a mechanical fault diagnosis method based on deep TensorProjection networks is proposed. In the proposed method，the feature of fault signal is extracted by high-order tensor spectrum，which is input into the constructed model for reducing high-order tensor dimensionality and identifying faults. The proposed method is applied to diagnose gearbox faults. Experimental results show that the proposed method can better retain the original fault information and effectively recognize the different types of faults. And the accuracy is better than traditional deep convolutional neural network fault diagnosis methods.

To address the threat of harmful vibrations of semisubmersible floating offshore wind turbine （FOWT） in complex deep-sea environments to the safety and durability，a design of distributed tuned mass dampers （TMDs） is proposed to control the platform pitch motion under the randomly combined wind and wave excitations，in combination with the geometric structure of the 5MW prototype of NREL in the United States. The distributed TMDs are installed inside the platform to form an equilateral triangle arrangement. To better describe the performance of the distributed TMDs on the semisubmersible FOWT，a 9-degree-of-freedom multi-body dynamics model is proposed and established for the coupled semisubmersible FOWT-TMDs system based on Lagrange's equation and the modal superposition method. Based on the H_∞ algorithm，whose optimization objective is the peak value of the frequency response function of platform pitch motion，the parameters of the distributed TMDs are optimally designed，where the coupling relationship between multiple TMDs is considered. The numerical simulation of the coupled FOWT-TMDs system under the combined wind and wave excitations is carried out to analyze the performance of the distributed TMDs on the platform pitch response of the wind turbine. The results show that the distributed TMDs with optimal design has good damping performance on the platform pitch motion of the semisubmersible FOWT. Under random wind and wave loads in three different working conditions，the peak and standard deviation vibration reduction rates of the power spectral density curve near the natural frequency of platform pitch can reach more than 39% and 52%，respectively. The research method and results can provide reference for dynamic analysis and vibration control design of large semisubmersible FOWT.

To reveal the influence of biaxial coupling effect on the multi-dimensional seismic performance of flanged reinforced concrete （RC） shear walls with different section forms，three T-shaped and two L-shaped RC shear walls were tested under low cyclic loading along their principal axes. The failure modes，hysteretic characteristics，bearing capacity，ductility，ultimate drift ratio，energy dissipation capacity and reinforcement strain of RC shear walls with flange under uniaxial and biaxial lateral loading were compared and analyzed. Test results show that failures of T-shaped walls and L-shaped walls exhibit obvious asymmetry，and the damage is concentrated at the free end of wall penal. Biaxial loading aggravates the cracking and damage degree of RC shear wall with flange，and is likely to cause local damage concentration. Compared with the RC shear wall with flange under uniaxial loading，the biaxially loaded specimens have smaller bearing capacity and deformation capacity in all directions，larger proportion of flexural deformation in the plastic hinge area of web segment，faster energy consumption，poorer energy dissipation capacity in a single direction，larger strains of vertical reinforcement in web and flange，and more obvious shear lag effect of flange. Biaxial coupling effect has more pronounced influence on the damage evolution of L-shaped walls than that of T-shaped walls，resulting in greater reduction of seismic performance index of L-shaped walls under biaxial loading than that of T-shaped walls. Considering the biaxial seismic actions，the limit value of inter-story drift ratio of RC shear walls in China's seismic design code is still relatively safe，but the safety redundancy is reduced.

Abnormal vibration often occurs in the liquid oxygen kerosene transmission pipeline of the rocket engine，which seriously threatens the safety of the rocket engine. Improper handling will result in a failed rocket launch and enormous economic losses. Therefore，it is necessary to study the vibration of the transmission pipeline. In this paper，a three-dimensional high pressure transmission pipeline model comprising a corrugated pipe，a multi-section bending pipe and other auxiliary structures is established.Using the two-way fluid-solid coupling method，the vibration analysis of the pipeline is performed under external pressure pulse excitation. The accuracy of the computation results is verified by a thermal test. The results show that at the same frequency，the amplitude distribution of vibration acceleration obviously correlates with the amplitude distribution of flow field pressure，which indicates that the fluid pressure fluctuation is the root cause of abnormal vibration of pipeline.And the vibration of pipeline increases with the increase of average pressure. In the visualization results，the location of pipeline vibration is mainly concentrated in the middle pipeline and bellows. The stress and strain of the pipeline are concentrated at the bellows，bends and supports，which is different from the distribution of vibration acceleration. The position with large stress and strain is the dangerous position where the structure is prone to failure，which should be paid more attention to.

In this paper，a set of overlapped and laminated foil aerodynamic bearings was developed，which was composed of overlapped radial bearings and laminated thrust bearings. Meanwhile，a rotor test bench of the foil aerodynamic bearings was designed and built. The take-off characteristics of the proposed foil aerodynamic bearings were studied by comparing the speed drop experiments of multiple groups of rotors. The influence of rotor unbalance and external load on the rotor dynamics of the bearing-rotor system was analyzed. The take-off test results show that the take-off speed of the radial foil pneumatic bearing developed in this paper is about 7500 r/min，and the maximum take-off torque is about 220 N·mm. The experimental results show that with the increase of rotor unbalance，the 1X frequency vibration amplitude increases gradually，the second critical speed decreases gradually，and the frequency of secondary frequency vibration increases gradually. With the increase of rotor speed，1X frequency vibration of the rotor system firstly increases and then decreases，and the amplitude of secondary frequency vibration increases gradually. When the center distance of the top foil structure is reduced，the stability of the rotor system increases. The experimental results show that both the unbalance and the external load excite the secondary frequency vibration of the system，and the amplitude of the secondary frequency vibration increases with the increase of the rotational speed. Moreover，the unbalance and the external load have obvious amplifying effect on each other in the excitation of secondary frequency.