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.

The electromagnetic performance of phased array antenna is greatly affected by the phased array antenna surface deformation. How to apply the strain measurement data of sparse fiber grating strain sensors to sense the shape of antenna array is the key to realize structural health monitoring and electromagnetic performance control. This paper proposes a virtual sensing method for structural deformation under complex experimental modes. In this method，the complex mode transformation is first used to process the complex mode data obtained from modal testing to obtain the corresponding real displacement modes，and then the full field expansion of finite real displacement modes is realized using mode expansion；Combining the extended real displacement modal and finite element modal data，two virtual sensing equations named CMT-SEREP（complex mode transformation-system equivalent reduction expansion process）and CMT-LC（complex mode transformation-local correspondence），which characterize the relationship between sparse measured strain information and the full field displacement of the structure，have been derived to achieve the real-time estimation of the deformation shape of the antenna structure from sparse measured strain information. Using the developed large phased array antenna array deformation experimental platform，experimental verification of different sensing methods was carried out under three deformation working conditions. Experimental results show that the proposed method can reconstruct the full field displacement of the antenna array structure using sparse strain measurement information，and the sensing accuracy of CMT-LC is higher than that of CMT-SEREP. Compared to the traditional modal method，the relative percentage error of deformation sensing using CMT-LC method has been reduced by at least 6.105%. This method is not only suitable for deformation sensing of non-proportional damping antenna structures，but also suitable for other complex engineering structures，and it has a great application potential.

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.

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 fuzzy domain of traditional fuzzy control is fixed，and the control efficiency will decrease when the dynamic characteristics of the controlled structure or external excitation changes. On the basis of traditional fuzzy control algorithms，a variable universe fuzzy control is designed. The variable universe fuzzy control takes the error and error rate of the controlled structure as input，and the scaling factor as output，achieving adaptive adjustment of the fuzzy domain of the main fuzzy controller. A two-story steel frame structure with a magnetorheological damper as the control device was constructed，and the variable universe fuzzy control system with the displacement and velocity of the first floor as inputs was developed in the dSPACE real-time simulation system. Shaking table tests under different intensities of seismic motion and different additional mass conditions were conducted. The results show that variable universe fuzzy control can adaptively adjust the fuzzy domain，effectively reducing structural displacement，velocity，and acceleration response. When the added mass of the controlled structure and the peak ground acceleration change，the control effect of variable universe fuzzy control is better than that of fuzzy control and OFF passive control.

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 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.

Inerters and negative stiffness devices can improve the energy dissipation performance of vibration absorbers. An increasing number of applications of them in novel high-performance vibration suppression have been witnessed. In this paper，analytical parametric optimization analyses on the tuned inerter mass systems with negative stiffness（NS-TIMS）are performed. A unified model of governing equations and transfer functions for NS-TIMS under different installation locations，application scenarios（such as inter-layer vibration absorption，and base isolation）and excitation types is established. Based on the fixed-point theory，the optimal parameters of NS-TIMS considering both H_∞ and H₂ norms are analytically derived. Considering typical application conditions，the analytical formulas are further analyzed and simplified. Consequently，the design formulas for the optimal parameters of NS-TIMS based on the“equivalent inertial mass ratio” are proposed. The application scopes of the design formula are discussed. Through numerical cases on the practical examples of wind-induced vibration control and seismic base isolation，the effectiveness of the design formulas considering the actual structural damping ratio and spectral characteristics of stochastic excitations is verified. It is also revealed that NS-TIMSs have superior performances in both high flexible structure vibration absorption and auxiliary base vibration isolation.

To enhance the accuracy of instantaneous frequency（IF）identification for non-stationary response signals of time-varying structures，a locally optimized multi-synchrosqueezing-short time fractional Fourier transform（LOMS-STFRFT）algorithm is proposed in this paper. Firstly，the local rotation parameters of the short time fractional Fourier transform（STFRFT）are optimally selected in this method. Subsequently，the time-frequency coefficient matrix projected to the fractional domain is obtained through STFRFT. After that，IF estimation and multiple iterations are performed on the time-frequency coefficient matrix. The time-frequency coefficient matrix is reassigned by the multi-synchrosqueezing operator，and IF curves are then extracted via the local mode maxima method. The accuracy of the proposed method is validated through a numerical example of a multi-component signal and a linearly time-varying cable test. The results demonstrate that the proposed LOMS-STFRFT algorithm behaves better than traditional multi-synchrosqueezing transform on IF identification of non-stationary signals from time-varying structures.

Ground motion simulation can provide reference for buildings seismic design in areas lacking earthquake records. High frequency attenuating factor （κ） is an important parameter in ground motion simulation，controlling the drop of Fourier spectrum shape in the high frequency interval. Luring magnitude 6.8 earthquake records within 150 km of the epicenter are selected to develop κ. Parzen window is used to smooth the cluttered Fourier amplitude spectrums （FAS）. The frequency interval in FAS with the smallest p^H function is selected to fit the κ. The approach improves accuracy of identifying lowest and upper frequency，and the stability of the calculation. κ are calculated based on 20 stations of horizontal records and the distribution trend of κ is analyzed. The results show that FAS is gradually smooth with the increase of the window width，and it is significantly different from the original spectrum when the window width is larger than 1 Hz. Compared with 12 window widths，the window width of 0.4 Hz is the best. The window of 0.4 Hz width makes the curve smooth and the error of κ small. There is a significant directional difference in κ distribution. κ in EW direction increases with respect to epicenter distance，and κ in NS direction decreases with respect to PGA.