As a method for operational modal analysis （OMA），the Bayesian FFT algorithm has garnerd significant attention for its high accuracy and efficiency，as well as its ability of uncertainty quantification. However，different cases of OMA （e.g. well-separated mode，closely-spaced modes，and multi-setup OMA） require different optimization strategy，and it is tedious in computer coding. A new framework is proposed in this paper to unify the above-mentioned cases of OMA，and the implement is simplified as a consequence. Regarding the structural modal response as a latent variable，the single-setup and multi-setup Bayesian OMA is cast as latent variable models，which have been deeply investigated in statistics. An expectation-maximization （EM） algorithm is developed for both single-setup and multi-setup OMA. The introduction of latent variables decouples the parameter optimization in EM，and Louis identity is employed to calculate the Hessian matrix. Two field tests are applied to verify the performance of the proposed approach，with a comparison to the existing algorithm. Consistent results are obtained，and a great advantage in efficiency is observed in the case of closely-spaced modes. The proposed latent variable model unifies the cases of Bayesian OMA，with the advantage of simplified implementation and fast computation. It also paves a way for a further improvement of Bayesian OMA，e.g. with the approach of variational Bayes or Gibbs sampling.

There are two kinds of stochastic seismic ground motion simulation methods： frequency-domain methods and time-domain methods. Based on the time-domain model of single filtered white noise，this paper proposes the time-domain representation for simulating stationary and non-stationary seismic ground motion processes. In essence，the time-domain representation can be regarded as linear superposition of deterministic functions modulated by a series of standard orthogonal random variables，and the set of orthogonal random variables is defined as the form of random orthogonal functions to achieve efficient dimension-reduction. Therefore，by introducing three kinds of random orthogonal functions，i.e.，Legendre orthogonal polynomial of non-Gaussian type，Hartley orthogonal basis and Hartley orthogonal elementary of Gaussian type，the acceleration process of seismic ground motion can be accurately represented in the time-domain model with only one elementary random variable. Numerical examples of seismic stationary ground motion process show the effectiveness of the proposed method，which is superior to the Monte Carlo method. The analysis of fully nonstationary seismic ground motion shows the engineering applicability of the proposed method.

In this paper，the effect of top drive control on stick-slip and bit-bounce was studied numerically based on a three-degree-of-freedom lumped parameter model considering coupling between axial and torsional vibrations of drill strings. The simulation results indicate that although the tuned k-c control can inhibit the stick-slip and bit-bounce the drill string vibration system to a certain extent，the suppression effect of stick-slip and bit-bounce in the drill string vibration system is not ideal when the input angular velocity is high and the nominal drilling pressure is low，or the input angular velocity is small and the nominal drilling pressure is large. The tuned I-k-c control can successfully eliminate the influence of input angular velocity and nominal drilling pressure changes on stick-slip and bit-bounce，so that no matter what the input angular velocity and nominal drilling pressure values are，the bit speed will remain stable around the given input angular velocity，reducing the fluctuation of WOB，TOB and axial displacement. Therefore，compared to top-drive tuned k-c control，tuned I-k-c control is more efficient in suppressing the stick-slip and bit-bounce of drill string vibration system.

In the realm of stochastic nonlinear response analysis for large and intricate structures，the Monte Carlo simulation method stands out as a pivotal approach. However，its widespread practicality is hampered by its exorbitant computational costs. To surmount this challenge，researchers have endeavored to develop the active learning-based Gaussian process surrogate model algorithm. Despite its promise in reducing computational expenses，the optimization strategy associated with active learning necessitates further refinement to meet the exacting demands of engineering applications. For this purpose，we introduce a search function endowed with ‘intelligent’ attention capabilities. This function is meticulously crafted to concentrate on exceedingly high-risk one-sided tail events in engineering scenarios. By incorporating this search function，we have engineered an algorithm that surpasses existing methodologies. Our algorithm finds successful application in the analysis of complex adhesive anchoring structures within subway tunnel rings and linings. Compared to conventional methodologies，our algorithm exhibits a remarkable 30% reduction in the estimation error of single-tailed probabilities. This advancement facilitates a more precise estimation of the one-tailed probability distribution governing the stochastic response of complex structures. Consequently，it enhances the precision of assessing the occurrence probability of extreme events. These findings yield invaluable insights for decision-making processes in pertinent engineering domains and insurance sectors.

Establishing human body dynamics model to obtain human natural vibration frequency is a common scientific challenge in various fields such as civil engineering，traffic engineering，aerospace，rehabilitation medicine and so on. The spring-mass-damper （SMD） model is most commonly used in previous studies，which actually is not consistent with the distribution characteristics of human mass and stiffness along the height. In this study，a distributed parameter dynamics model of the human body with a pair of biomechanical forces is proposed，and the analytical solution of human natural frequency is theoretically derived. Therefore，a frequency recognition method based on gait tests is proposed. 247 subjects are organized to conduct gait tests，and their stiffness and natural frequency are identified. The rationality and applicability of the proposed model are verified from multiple perspectives： by fitting the probability distribution of results，comparing the results with other researches，and analyzing the results across different age groups.

The durability issue of multi-age masonry structures subjected to acid rain has become increasingly prominent，but a complete time-varying model of structural durability has not been formed at home and abroad. To study the relationship between the evolution of material properties and masonry properties，accelerated corrosion tests were carried out on mortar with different mix ratios，bricks，and masonry，and a compressive strength model of masonry components considering the number of acid rain erosion cycles was established. Based on the sample data of masonry in natural environment，the mathematical relationship between the degradation degree of mechanical properties of in-service masonry structures and their service life under the action of acid rain erosion was established. The typical structure method was used to analyze the seismic fragility of a two-story constrained masonry structure，and the influence of different parameters on the fragility curve and failure probability of constrained masonry structures under acid rain erosion was discussed. The results show that the probability of severe damage and collapse of restrained masonry structures under the action of acid rain erosion increases gradually with the increase of service life under the condition that other factors remain unchanged and the intensity of local vibration is higher.

In the phenomenon of brake noise，the parametric uncertainty and correlation inevitably exist in the automotive brake systems，leading to some uncertainty and correlation of the system response. To address this problem，the uncertainty and correlation analysis for the stability responses of brake systems was carried out. A multi-ellipsoidal convex model was used to depict the uncertainty and correlation of system parameters，and the stability responses of system were characterized by the unstable modal damping ratios. The Monte Carlo simulation，the first-order perturbation method and the second-order perturbation method were respectively combined with the multi-ellipsoidal convex model respectively，and three uncertainty analysis methods of system stability responses were proposed. Based on the Monte Carlo simulation and the first-order perturbation method，two correlation analysis methods of system uncertain responses were developed respectively. The combinatorial methods for establishing the ellipsoid domains of system responses were presented by combining the uncertainty analysis and correlation analysis methods. A numerical example was given to verify the effectiveness of the proposed methods. The analysis results demenstrate that the proposed methods can effectively obtain the boundary intervals，correlation coefficients and ellipsoid domains of system responses，and the methods have high computational accuracy and efficiency.

Stochastic subspace identification （SSI） generates spurious modes in the process of identifying the dynamic characteristics of high-rise structures，which interferes with the automatic tracking of dynamic characteristics. This article has proved that the non-white noise excitation is one of the causes of spurious modes，and further proposed a signal reconstruction method based on multivariate variational mode decomposition （MVMD） for non-white noise excitation，which removes the influence of non-white noise excitation in signals and eliminates spurious modes. A Single-Pass clustering algorithm is proposed to eliminate discrete spurious poles. The above algorithm has been applied to on-site monitoring data of super high-rise structures，achieving long-term automatic identification and tracking of dynamic characteristics.

Aiming at the issue of inter-shaft bearing waviness in a dual rotor system，the dual rotor-bearing system of external rotor with variable cross section was taken as the research case. The dynamic model of the dual rotor-bearing system was established based on the Finite Element Modeling （FEM）. The waviness of the inner and outer ring raceways and the rolling body of the inter-shaft bearing were considered in the model. The fourth order Runge-Kutta numerical method was used to solve the equations，and the influence of waviness excitation on the amplitude-frequency response curve and spectral characteristics of the system was analyzed. The results show that when there is waviness in the inner and outer ring raceways，the system exhibits a combination frequency of the inner and outer rotor rotation speed frequency as well as cage rotation speed frequency. And when there is waviness in the rolling body，the system has an even times of the rolling body self-rotation speed frequency. When the rotor is unbalanced，the outer ring raceway waviness will amplify vibrations in the resonance region of the outer rotor main excitation. The vibration of the system will increase in the whole speed range with the increase of the waviness amplitude，while the vibration responses of the inner ring raceway waviness and the unbalanced excitation will appear similar to the same frequency and reverse phase phenomenon in the second resonance region of the inner rotor main excitation. The vibration of the system will decrease with the increase of waviness amplitude，while the vibration in other regions will increase. Compared with the high rotating speed region，the waviness of the rolling body significantly impacts on the vibration characteristics in the low rotating speed region.

In order to reduce the tube area proportion of the traditional frame-core tube （FCT） structure system and improve the structural economy，a high-rise structural system of the frame-distributed tubes-core tube （FDCT） is designed. The distributed tubes and rocking system are combined to form the frame-distributed rocking tubes-core tube （FDRCT） structural system，which can control the deformation mode of the structure. To reduce the adverse effects of higher modes on high-rise structures，the frame-distributed bi-rocking tubes-core tube （FDBRCT） structural system with tuned damping performance is further proposed. The dynamic models and equations of the structure are established，and the stationary random vibration analysis is carried out，which preliminarily proves that the FDBRCT structure can reduce the dynamic response of the structure more effectively. By comparing and analyzing the structural time-history analysis results of the FCT，FDCT，FDRCT and FDBRCT，the seismic capacity of the FDCT structure decreases is due to the stiffness weakening. The FDRCT structure improves the uniform degree of structural deformation，and the upper floors acceleration decreases，but the roof displacement increases. Compared with the FDRCT structure，the maximum of inter-story drift ratio of the FDBRCT structure increases significantly and the structural deformation is more uniform. Besides，the roof displacement response and internal force demand decrease appropriately. The distributed bi-rocking tubes with tuned damping brings on better seismic capacity and damping performance of the FDBRCT structure，which can improve the economy at the same time.