The variable-length dual-flexible manipulator is composed of a flexible joint and a flexible load，which is affected by flexibility，friction，and time variation of parameters. It will vibrate in the process of moving，which will reduce the tracking accuracy of the end-effector. In this paper，the fuzzy tuning PI control strategy based on disturbance observer is used to control the output speed of the dual-flexible manipulator servo system. The vibration of the manipulator can be suppressed indirectly by controlling the speed fluctuation of the flexible load. Based on the assumed modal method and the Lagrange principle，the dynamic equations of the dual-flexible manipulator are established. A low pass filter in the disturbance observer is designed according to the robust stability theorem，so that the disturbance observer can satisfy the stability of the controller parameter time-varying and the controlled object parameter perturbation jointly. The effectiveness of the proposed method is verified by numerical simulation and control experiments of the dual-flexible manipulator servo system. The experimental results show that the proposed control strategy can better eliminate the influence of parameter time-varying and flexibility on the output speed，and improve the control precision of the end-effector.

The synchronization factor is a measurement for the consistency of actions between individuals in a jumping crowd，as well as a key metric in the modeling of crowd jumping loads. Most of the existing synchronization factors are defined as mean parameters during a long period of time，and thus cannot accurately reflect the time-varying characteristics of individual differences between jumpers. Their calculation is based on ground reaction force or feature point trajectory records that can only be obtained under laboratory conditions，making it difficult to apply them to the safety operation and maintenance of the engineering structures in actual scenarios directly. In this regard，this paper proposes a new time-varying synchronization factor for crowd-jumping loads. By introducing multiple objects tracking technology to monitor the real-time synchronization variation of the subject jumping processes as the basis for the factor calculation，this study carries out a multi-person jumping experiment with a wireless force measurement shoe pad. By comparing with the test results，the validity of the proposed time-varying synchronization factor and the effectiveness of the multi object tracking technology are verified. The results can be used for the intelligent operation and maintenance of the engineering structure，as well as the simulation of the time-varying crowd jumping loads.

With the rapid development of offshore wind power in recent years，the floating offshore wind turbine is proposed to capture more abundant and lasting wind energy in the deep sea，which has become the main direction of wind energy development. Due to the special structures and complex environment，the accurate calculation and analysis of floating offshore wind turbines will be particularly important for a multi-body system. In this paper，the coupling dynamic model of a floating offshore wind turbine is deeply studied. The improved 14-DOF coupling dynamic model of spar floating offshore wind turbine under complex working conditions is established，including an aerodynamic model，hydrodynamic model and structural analysis model，which can accurately calculate its dynamic response and verified by numerical simulation. The main improvements are as follows： expanding its scope of application without using small approximation of the angle in the coordinate rotation matrix； considering the conversion relationship between angular velocity and Euler angular velocity，the motion equation of floating offshore wind turbine with wider application range and more accuracy is derived. Besides，considering the influence of fan blade torsion angle on blade deformation，the accurate in-plane and out-of-plane response of the blade is obtained. Meanwhile，the potential flow theory is used to calculate the hydrodynamic force in order to solve the limitations of the traditional Morison equation algorithm. The simulation analysis shows that the model proposed in this paper can calculate the dynamic response of floating offshore wind turbine system more accurately with wider applicability.

Aero-elastic model wind tunnel test is carried out for a 1/3 rise-span ratio capsule-shaped pneumatic membrane structure，the characteristics of the wind-induced aero-elastic response of the structure are studied and the wind-induced dynamic vibration coefficients for practical design reference are given. The research confirms that the averaged deformation of the structure shows a trend of windward depression，top uplift and outward bulge in the transverse direction. This deformation trend is increasingly obvious with the decrement of internal pressure and the increment of wind speed. The averaged deformation and vibration amplitude decrease when the wind direction ranges from 0° up to 45°，then to 90°，and the extreme value of structural mean total displacements tends to appear at the center points of windward surface and top surface. Under 0° and 45° wind directions，the sort of vibration amplitudes of different components is vertical component，along-wind component and cross-wind component in descending order. Moreover，the structural vibration is dominated by the first-order mode. Under 90° wind direction，the amplitude of the crosswind direction is greater than two other directions，and the wind-induced vibration is dominated by the superposition of the first and second order modes. The internal pressure of the structure decreases in different extents under all cases. The response-based wind-induced dynamic vibration coefficients considering the fluid-structure interaction effect are given.

The II-shaped composite girder is widely used in the construction of long-span cable-stayed bridges，but the weak vortex-induced vibration （VIV） performance of this type of section seriously limits its application prospects. A II-shaped composite girder double-tower cable-stayed bridge with a main span of 530 m is used as the engineering background，and the VIV performance and aerodynamic optimization measures of the II-shaped composite girder are studied by using wind tunnel tests. The tests show that the VIV of the original II-shaped section occurs at each wind attack angle，and the VIV amplitude of the girder can be reduced by setting guide vanes and the lower central stabilizer. The change in the inclination angle of guide vanes has a significant impact on the combined aerodynamic measure of VIV suppression performance. The combination measure VIV suppression performance with the guide vane of 30° inclination angle is the best，and the VIV can be significantly suppressed or even eliminated when the damping ratio required by the specification is 1.0%. The VIV suppression mechanism of the combined aerodynamic measure and the influence mechanism of the guide vane inclination angle change on the VIV suppression performance of the measure are studied by using computational fluid dynamics （CFD） numerical simulation. The calculation results show that the windward side guide vane in the 30° inclination guide vane combination measure can significantly improve the gas flow around the upstream section，and the cooperation with the lower central stabilizer can weaken the Karman vortex of the II-shaped section wake toy suppress the girder VIV. Changing the inclination angle of the guide vane not only affects the generation of vortices near the guide vane itself，but also affects the improvement of the lower central stabilizer on the vortex shedding state under the section，thereby significantly affecting the VIV suppression performance of the combined aerodynamic measure.

To enrich the measured database of the modal parameters of the long-span cable-stayed bridge，based on the data collected by the structural health monitoring system of the Sutong Bridge，the modal parameters of the bridge during 2010 are obtained using the established automated modal identification and tracking method. On that basis，the variability of the modal parameters of the bridge with the changing temperature and wind speed is analyzed. Results show that the frequency of the bridge is controlled by both temperature and wind speed. The frequency decreases with the increased temperature and increases with the increased wind speed. The variability of the damping ratio of the main girder of the bridge is significantly greater than that of the frequency. The damping ratio of the first-order lateral bending modes of the main girder fluctuates between 0.5% and 15% at low wind speed interval. It gradually decreases and stabilizes at about 2% when the wind speed is greater than 9 m/s. The damping ratio of the first four vertical bending modes of the bridge is mainly affected by the aerodynamic damping. It increases slightly with the increase of wind speed at the low wind speed intervals. The obtained results can provide a reference for assessing the in-service performance and issuing operational management of the bridge.

In order to solve the problem of complex nonlinear vibration response in the traveling vehicle system，a nonlinear dynamical model for a coupled human-vehicle-road system with three-degree-of-freedom is established. The coupled vibration equations of human-vehicle-road with three-degree-of-freedom are derived by the Lagrange equation，and the sine and cosine functions of this system arise from the geometric nonlinearity of torsional deformation. The nonlinear restoring force surfaces，potential energy surfaces and analytical expressions of natural frequency are obtained for the free vibration of the human-vehicle-road system. For the forced vibration，the influence of vehicle system parameters of vehicle mass，moment of inertia，passenger mass，seat stiffness，suspension stiffness，damping，centroid position，road wavelength and wave amplitude on the response curves of amplitude velocity is analyzed by using the numerical simulation method. The experimental platform of the coupled human-vehicle-road vibration system is built and the reliability of theoretical analysis and numerical results is verified by the experiments. The results show that this nonlinear dynamical coupled system with three degree-of-freedom can accurately describe the human-vehicle-road response characteristics，and reasonable selection of the system parameters can effectively reduce the vibration response amplitude and improve the human riding comfort.

The constant erosion of ocean waves seriously affects the safe operation and service performance of ocean engineering equipment，and ocean wave energy is a green renewable energy with many advantages. How to reduce the wave load and utilize the ocean wave energy through the hybrid wave attenuation and energy harvesting structure is one of basic scientific problems in the field of ocean engineering. The traditional wave attenuation and energy harvesting structure，especially the floating structures in the deep sea，has the technical bottleneck of wave attenuation and energy harvesting at a low frequency range. In this paper，based on the idea of reducing the equivalent dynamic stiffness of the system，a nonlinear hybrid wave attenuation and energy harvesting structure is proposed，and the characteristics are studied. A new type of negative stiffness mechanism is designed and applied to hybrid wave attenuation and energy harvesting structure. In order to solve the fluid-structure interaction problem of nonlinear hybrid wave attenuation and energy harvesting structure，a semi-analytical nonlinear frequency domain method of hybrid eigenfunction expansion matching method and multi-harmonic balance method is proposed. The influence of the key parameters of the mechanism on the wave attenuation and energy harvesting performance is studied，and the “phase control” mechanism of the negative stiffness mechanism to improve the low frequency wave attenuation and energy harvesting performance is revealed.

Considering the simply-supported cylindrical shells，the modal participation in dynamic responses is studied by considering the influence of sine and cosine modes，and a method for determining the order of modal truncation according to the distribution characteristics of modal participation factors is proposed. The dynamic responses of cylindrical shells under the impact excitation and rotating traveling wave excitation are obtained by the superposition of the sine and cosine modes，and the reliability of the determination method is verified by the convergence of responses. The results of theoretical calculations and finite element simulations show that the influence of sine and cosine modes must be considered simultaneously in calculation of the dynamic responses for cylindrical shells，which is different from the case of modal characteristics analysis. When cylindrical shells are subjected to impact excitation，the participation degree of each order sine and cosine modes is related to the location of the excitation point and observation point. When cylindrical shells are subjected to rotating traveling wave excitation，the participation degree of each order sine and cosine modes is closely related to the order and frequency of the excitation.

The robust dynamic topology optimization of a continuum planar structure is studied to reduce its natural frequency variation when the structural material parameter uncertainties are considered. The uncertainties of the material properties are represented with the uncertain-but-bounded interval variables based on the non-probabilistic convex model. The dynamic topology optimization model for maximizing the first natural frequency is constituted by mitigating its variation，such that the robust optimization problem can be simply solved into a single-level framework. By the derivative analysis of the material parameters，a quadratic Taylor series expansion of the first natural frequency is obtained，and the design sensitivity of the natural frequency is accordingly evaluated in an explicit form under the uncertain material properties. By means of the material density-based strategy，the robust dynamic topology optimization is implemented with the material volume constraint，and the results are compared with those of the deterministic topology optimization. Optimal results show that the first-order natural frequency obtained with the proposed method has a higher robustness against the material property uncertainties，which fully demonstrates the importance of considering the uncertainties of the material parameters in the structural design stage.

The construction of a new power system requires to improve the response time of pumped storage units. In this paper，taking a specific pumped-storage unit as an example，systematical research is performed on the main differences of sequence control process and the variation law of unit stability parameters under normal and fast pumping to generating mode. Based on that，the inverse-time vibration evaluation method is introduced to evaluate the impact of transition modes on the unit vibration peak-to-peak values. By analyzing the pressure fluctuation in the vaneless zone with the frequency spectrum analysis method，the phenomenon of hydraulic resonance in the vaneless region at low speed is found in generating rotation，and the correlation between resonance amplitude，frequency and speed is revealed. The research indicates that the mode transition from pumping to generate the fast transition is better than the normal transition. Compared with the braking method of electrical brake plus mechanical brake in normal transition，the hydraulic braking mode under fast transition can significantly shorten the transition time from 438 s to 220 s. From the perspective of vibration damage to the unit，13 of the 14 vibration and runout monitoring points prove that fast transition is conducive to prolong the expected life of the unit. Meanwhile，the fast transition is favorable to pass the hydraulic resonance occurring in vaneless zone at low speed. The hydraulic resonance time is reduced from 15 s in normal transition to 5 s in the fast transition，and the resonance speed range is compressed by more than 60%.

Aiming at the problem that the current traditional vibration sensor is limited by the installation and the number of measuring points when measuring the displacement of the rotating body，this paper uses a high-speed industrial camera as the acquisition medium，and collects the rotor vibration video on the rotor vibration test bench. The visual vibration measurement method tracks the full-field vibration displacement of multiple rotor targets. The feature pyramid network structure is introduced into the residual neural network，and the improved feature extraction backbone network is established by combining the attention mechanism. The identity re-identification method is used to strengthen the correlation of target displacement between adjacent frames，and to track the full-field vibration displacement signals of the rotator. Qualitative and quantitative comparisons of different network models on the rotor vibration displacement measurement dataset show that the network model proposed in this paper can obtain a tighter fit when the bounding box is regressed. The collected eddy current displacement signal is used as the standard value to compare the two rotor displacement signals，and the experimental results show that the waveform and spectral noise fitted by the multi-target tracking algorithm in this paper is the smallest and can match the eddy current signal. The experiments also prove the generalization performance of the algorithm in this paper，which reflects the engineering application value of visual measurement in the field of vibration displacement tracking of rotating bodies.

The determination of the rocking state for an isolation structure is a fundamental issue to estimate the safety of the isolated layer under a seismic excitation. In this study，by using the tensile deformations at the vertical direction of the rubber support in the isolated layer，the rocking states of the isolation structure are divided into ones with unuplifting，uplifting，and rocking. A classification method is then proposed for estimating the rocking state of the high-rise structure with isolated layer. Inspired by the influences of the aspect ratio （AR），vertical yield-weight ratio （α_v），horizontal yield-weight ratio （α_h），vertical cycle （T_v），horizontal cycle （T_h），system damping ratio（η） to the swing response of isolation structures under seismic excitation，boundary spectrum of isolation structures is achieved. It shows that swing response decreases with the increase of α_v，T_h and η （the effect of T_h is most significant），which is beneficial to the control of the sway response as well； swing response increases with the increase of AR and T_v （the effect of T_v is most significant），which is not conducive to the control of swing response，and the most advantageous measure to control the swing response is increasing T_h，decreasing T_v.

In order to cope with excessive displacement requirements of the isolation layer in the base isolated structure，a hybrid isolation system is proposed in this paper through the base isolated system （BIS） + tuned tandem mass dampers-inerters （TTMDI）. The Bouc-Wen hysteretic model is used to simulate the nonlinear force-deformation behaviors of the isolation layer. Employing the stochastic equivalent linearization，pattern search optimization algorithm，as well as the earthquake ground motion model simultaneously，the optimum design framework of the BIS+TTMDI system is established in the frequency domain. The performance of the BIS+TTMDI system is systematically evaluated in terms of its robustness，effectiveness，stiffness and damping coefficient，stroke and sensitivity to seismic frequency contents，and compared with BIS + the tuned mass damper （TMD），tandem tuned mass damper （TTMD），and tuned mass damper-inerter （TMDI），respectively. The dynamic elasto-plastic analysis of a seven story hybrid base-isolated system，respectively including the BIS+TTMDI and BIS+TMDI systems，is carried out under the near-field earthquake ground motions. The results show that the BIS+TTMDI system has the best seismic performance and strong robustness. Furthermore，the total damping requirement of the TTMDI in the BIS+TTMDI system is less than half of the TMDI in the BIS+TMDI system，which is more economical and practical.

In order to improve the application of the damping force of isolation device for free-standing objects，a new damping mechanism is developed. Its structure and working mechanism are expounded，and its mechanical characteristic is deduced and verified. Combined with the target performance of an isolation device for cultural relics，the parameters of the damping mechanism are designed by numerical method，and contrasted with the shaking table test. The results indicate that the damping mechanism has a simple structure and stable performance. The isolation device optimized by damping parameters achieves the set isolation target under the premise of meeting the displacement limit. The test results are highly consistent with the numerical analysis results，which not only prove the correctness of the damping design，but also verifies the installation quality and operation effect of the isolation device. In addition，the coincidence degree between two results can provide a new method for design comparison and quality evaluation of the isolation device，especially the coincidence degree of relative displacement curves.

The one-dimensional and two-dimensional time-domain inversions of the bedrock incident waves cannot reflect the spatial arbitrariness of the incident azimuth and oblique incident angles，and the free field constructed based on these two methods might deviate is far from reality. It is necessary to carry out a three-dimensional time-domain inversion of the bedrock incident waves. Based on the wave function combination method，the free field of the ground surface control point is expressed by the time histories of the incident waves of P，SV and SH waves. A three-dimensional time-domain inversion method of bedrock incident waves based on design ground motions is established. Then，the spatially non-uniform free field under the oblique incidence of multi-wave combination is constructed. Finally，the free field deviations constructed based on one-dimensional and two-dimensional inversion methods are analyzed，and the influence mechanisms of different inversion and free field construction methods on the seismic response of the asphalt concrete core dam are revealed. The results show that the free field constructed based on the three-dimensional inversion method of ground motion has spatial inconsistency and can reflect the site ground motion field more comprehensively. Compared with the ground motion field constructed based on three-dimensional inversion，when the incident azimuth angle is 0°~60° and the oblique incident angle is 40°~90°，the feature point free field in the x-direction constructed by the one-dimensional inversion method has a large deviation with the maximum deviation55.8%； When the incident direction is parallel to a certain horizontal coordinate axis，the other horizontal free field deviation of the feature point constructed by the two-dimensional inversion is larger，and the maximum deviation is 100%； When the Poisson's ratio of the medium increases，the deviation of the x-direction free field decreases under the one-dimensional inversion，and the free-field deviation of the x-direction increases under the two-dimensional inversion，and the maximum deviations of the feature points are 46% and 36%，respectively. Compared with the maximum tensile stress of the core wall based on the three-dimensional inversion method of ground motion，the maximum tensile stresses under the two-dimensional and one-dimensional inversion methods are reduced by 83.3% and 20.0%，respectively. Therefore，it is necessary to perform a three-dimensional inversion of bedrock incident waves and construct a spatially non-uniform free field based on the design ground motion in the seismic design of dams.

Based on the actual project in Dalian，this paper studies the dynamic interaction （SSSI） of the double tunnel sand bridge pile system under earthquake through shaking table test，obtains the dynamic response law of structure and site，and compares it with ABAQUS numerical simulation. The Kelvin constitutive model subroutine is introduced into the numerical model，and the equivalent linear method is used to deal with the nonlinear problem of sand in the calculation process. The experimental results are compared with the numerical model to verify the reliability of the numerical simulation. On this basis，eight working conditions are designed，and the interaction law between structures in the system is studied through comparative analysis. The results show that the tunnel will amplify the peak acceleration of the bridge pile and adjacent tunnel，but the bridge pile will weaken the peak acceleration of the side tunnel； the existence of the tunnel and bridge pile will increase each other's section shear force and bending moment. The main affected areas are concentrated in the upper and lower arches of the tunnel and the interface between the pile bottom of the bridge pile and the pile-soil.

With the advent of the era of big data，the mechanical equipment fault diagnosis method based on deep learning has attracted more attention. However，the traditional deep network model seriously limits its application in practical engineering due to the excessive amount of parameters and calculations. Based on this，a GhostConv lightweight network model is proposed and used for fault diagnosis. GhostConv generates a small part of the feature maps through conventional convolution，and performs multiple feature extraction on the generated feature maps to generate the remaining feature maps. Contact the feature maps of the two parts to obtain a complete feature map. GhostConv structure saves the cost of generating redundant feature maps in conventional convolution to the maximum extent，and reduces the model parameters to ensure the performance of the model. In the experiment，the continuous wavelet transform is used to transform the vibration signal to generate a two-dimensional time-frequency diagram，and then the designed GhostConv is used to establish a lightweight fault diagnosis network model. The original dataset and noisy dataset of Case Western Reserve University are used for experimental verification，and compared with the conventional convolution structure network model and depth separable convolution structure model in terms of parameters，calculation and recognition rate. The experimental results show that the GhostConv lightweight network model still has high recognition accuracy and strong anti-noise ability under the condition of fewer parameters and calculations with good robustness and generalization ability. The parameters of the model are only 6% of the conventional convolution model and 56% of the deep separable convolution model. Under the condition of strong noise interference，the fault diagnosis and recognition rate is still higher than that of the conventional convolution model，which confirms its engineering application value.