The flexible structure in probe-drogue aerial refueling system often occurs the hose whipping phenomenon in different degrees，which greatly affects the safety of aerial refueling mission. Based on flexible multibody dynamics，a dynamic model of aerial refueling system is built. The large deformation，large-scale movement and variable length characteristic of the hose are described by beam element that based on arbitrary Lagrange-Euler description and absolute node coordinate method. The aerodynamic model on the aerial refueling system is built，which can reflect the coupling effect between the movement of the tank and the receiver，the deformation of hose and aerodynamic force. Based on the dynamics model，the hose whipping phenomenon in flight is reproduced，and the formation mechanism of the phenomenon is obtained. The research shows that the docking impact is the main cause of whipping phenomenon，which changes the equilibrium state of the hose and causes shear waves to propagate and reflect back. The results of multi-case simulation are used for analyzing the influence law of various factors，including hose stiffness，docking speed and Mach number，on the shear force，longitudinal wave and shear wave propagation speed of the hose when whipping phenomenon happened. The effectiveness of hose reeling in/out control and buffered probe for vibration suppression of hose whipping phenomenon is also analyzed，which provides an important reference for improving the safety of probe-drogue aerial refueling system.

Stay cables of cross-sea cable-stayed bridges will generate self-excited vibrations in non-extreme wind environments. Based on technologies of modern monitoring and data analysis，the digital features of the self-excited vibration of the stay cable can be captured immediately，and the real-time performance of dynamics about stay cables can be reflected accordingly. According to features of commonality in the long-term monitoring data of vibrating acceleration of stay cables from a main channel cable-stayed bridge of a cross-sea bridge，an automatic extraction method for the non-stationary sections of wind-induced self-excited vibration of the stay cable is proposed based on the vibrating acceleration time series signal’s Gaussian mixture model of the upper envelope and the power spectrum of the frequency domain. The strategies，that identify the dominant frequency based on the non-stationary time series of self-excited vibration，then identify the damping ratio using the data of the last descent section after band-pass filtering，are proposed. By the proposed strategies，the interference on the damping ratio identification from energy brought by the natural excitation of the ambient wind in the ascent sections of the vibration amplitude is excluded. Based on the identified results of dominant frequency-damping ratio in the non-stationary sections of the self-excited vibration，data clusters of the modal frequency-damping ratio corresponding to each order of the vibrating mode are obtained by clustering the frequency values. According to the discrete and skewed characteristics of the damping ratio data，the statistical law of using the eμ of log-normal distribution model and the quantile value of its cumulative distribution function to describe damping ratio of stay cables is proposed. The frequency centroid of each cluster，as well as the probability characteristic parameter of damping ratio are used as indicators to represent the current state of the dynamic performance of stay cables. The main conclusions for the background engineering include： the signal of vibrating acceleration of stay cables on the bridge has strong noise and large interference，they must be eliminated in the analysis of dynamic characteristic； the amplitude maximum of the acceleration of the self-excited vibration of the bridge’s stay cable has exceeded 3000 mm/s²，the vibration amplitude is large； the average level of the damping ratio of the bridge’s stay cable is about 0.03%，which is lower than the recommended value of the design code.

In order to accurately analyze the influence of temperature and shear deformation effects on the natural vibration characteristics of the improved composite box girder with corrugated steel webs，a method for analyzing the natural vibration characteristics of an improved composite box girder with corrugated steel webs considering temperature and shear deformation effects is proposed in this paper. Considering the influence of the temperature，shear deformation and stiffness correction of the corrugated steel web，the analytical formula of the natural frequency of the improved composite box girder with corrugated steel webs is deduced by using the principle of stress equivalence； The correctness of the analytical formula of natural frequency is verified by using the ANSYS finite element results and the measured results of bridge； The effects of temperature equivalent axial eccentric force，variation of elastic modulus，shear deformation，and temperature effect under different height-span ratios and different width-span ratios on the natural frequencies of bridge are analyzed. The results show that the fundamental frequency of the improved composite box girder with corrugated steel webs is greatly affected by the temperature effect，and the influence of the temperature effect needs to be considered when calculating the fundamental frequency of this bridge type； The shear deformation effect of the corrugated steel web has a significant influence on the natural frequencies of the bridge type，and the influence of shear deformation from the 4th order natural frequencies has exceeded 50%； Under different height-span ratios，the temperature effect has a greater influence on the fundamental frequencies，and it increases linearly and sharply with the increase of the height-span ratios； Under different width-span ratios，the temperature effect has little influence on the natural frequencies and can be ignored. The research results can provide a reference for the calculation and analysis of the natural frequencies of the improved composite box girder with corrugated steel webs.

Aimed at the problem of limited placement of error microphones in large-scale spatial active noise reduction systems，this paper used the virtual error sensing technology to place multiple virtual error microphones in the noise reduction target area，and transferred the quiet zones from the physical error microphone points to the virtual error microphone points，expanded the range of the quiet zones in the noise reduction target area. In order to analyze and study the noise reduction performance and influencing factors，the principle and algorithm of multi-channel virtual error sensing were given first，and then the noise reduction performance and the number and placement of physical and virtual error microphones ware simulated and analyzed. Finally，the noise reduction performance and influencing factors were verified experimentally in a model cabin of a turboprop aircraft. The simulation and experimental results show that the used virtual error sensing was beneficial to increase the average noise reduction and quiet zone of the target noise reduction area，the placement of the physical and virtual error microphones directly affects the distribution of the quiet zones，a reasonable number and placement of physical and virtual error microphones can expand the quiet zones to cover the noise reduction target area 100%，and the optimal number of error microphones was related to the noise frequency characteristics of the primary sound field.

Most of the nuclear power plants are built around the coastal or along the rivers. Below the underground water level，distribution of the water in the soil pore has a great influence on the seismic response of soil，which affects the response of the nuclear power plants. To analyze the effect of the underground water level on the seismic response of nuclear power plant，a saturated porous medium model considering the interaction of the saturated soil and structure is used in this paper. Firstly，the free field of the horizontal layered site of dry soil-saturated soil is obtained by the transfer matrix method，and the wave input of soil-structure interaction analysis is realized combined with the transmission boundary； Then，the partitioned parallel calculation method of soil-structure interaction is used to analyze the saturated soil-structure interaction. The soil with groundwater level is described by the generalized saturated porous medium model which is simulated by the lumped-mass explicit finite element combined with the transmission boundary using the self-programmed FORTRAN code，and the structure is analyzed by ANSYS using implicit finite element. Taking a nuclear power plant as an example，the dynamic response of soil-base-nuclear power plant system is analyzed in five sites with different groundwater levels of -10 m，-20 m，-30 m and -40 m，as well as pure saturated soil. The results show that the groundwater level has a great influence on the response of foundation and structure. For the calculation example in this paper，the results show that the groundwater level has little effect on the displacement of the foundation and structure，but has a great effect on the acceleration of the foundation and structure.

Honeycomb sandwich panels are widely used in aerospace and other major equipment because of their light weight and excellent mechanical properties. The acoustic performance，however，is a significant flaw. In this study，a sound insulation prediction model of infinite honeycomb sandwich panel is established based on the Bloch theorem and the wavenumber finite element method. The honeycomb sandwich panel is simulated with a periodic cell. By analysing the dispersion characteristics of the honeycomb sandwich panel in the wavenumber domain，the sound insulation mechanism under the excitation of diffuse sound field is revealed，and the influence of geometrical parameters on the sound insulation performance of the honeycomb sandwich panel is investigated. The results demonstrate that below the critical frequency，the sound insulation of the honeycomb sandwich panel is mainly controlled by the mass law，while above the critical frequency，the sound insulation is also impacted by the structure's own feature wave. When the incident acoustic wave excites the resonance of the feature wave，the sound insulation fluctuates with frequency and generates a sound insulation valley. The effect of thickness variation on the sound insulation performance is primarily related to the amount of sound insulation below the critical frequency，the thicker the honeycomb sandwich panel，the higher the amount of sound insulation； height increase reduces the mass law control zone and shifts the first sound insulation valley to lower frequencies，resulting in a weakening of the overall sound insulation performance. The relevant research results can provide a reference basis for the design of vibration and noise reduction of complex structures.

Intelligent fault diagnosis of rolling bearings is important for guaranteeing the safe of equipment. However，the non-stationary conditions lead to the incomplete collected training datasets，which makes the data-driven model learn the limited diagnostic knowledge. This declines the testing accuracy observably. To solve this problem，a Standard Self-Learned Data Augmentation （SSDA） fault diagnosis method is proposed，which can generate disturbed samples to expand the completeness of the original dataset. The method includes two training steps： standard self-learning and data augmentation. The training process of one-dimensional convolutional neural network is regarded as the self-learned standard of model to judge disturbed samples. Based on this standard，sample parameterization and model datalization are used to generate disturbed samples. By alternately carrying out the two steps，not only the disturbed data can be generated to augment the completeness，but also the fault diagnosis model under non-stationary conditions can be obtained. In addition，by studying the sample differences with different data generating number，it is found that the randomness of distance and direction is superimposed on the randomness of the proposed method to guaranteeing the diversity of the generated samples. Experimental results show that the proposed method is effective and advantageous in diagnosing bearing fault with incomplete training data sets under non-stationary conditions.

The braking torque of the carbon ceramic braking system of the landing gear increases with the reduction of wheel speed under the condition of rapid change of angular speed. The negative slope of the braking torque and wheel speed curve has a great relationship with the landing gear walking vibration. Focusing on the impact of the negative slope of the braking torque on the landing gear brake vibration，a three degree of freedom landing gear brake walking model is established，and the main landing gear brake vibration of amphibious aircraft is analyzed. The calculated acceleration response and frequency are consistent with the test results of the landing gear field skid brake test. The effects of initial braking torque，negative slope，landing gear heading stiffness and damping，strut equivalent height and other parameters on the landing gear dynamic system are studied，and the dual parameter vibration convergence boundary of initial braking torque and negative slope of braking torque under high speed braking is given. By means of Hopper bifurcation analysis，the two parameter stability boundary of the negative slope of braking torque and velocity under the global state of the landing gear system is given. Through analysis，it is concluded that the gear walk may be caused by two reasons： the negative slope of the braking torque exceeds a certain range，or the braking torque is too large due to large braking pressure，and the slip ratio exceeds the limit. Compared with high speed braking，the negative slope of braking torque has greater influence on the stability of low speed braking. Finally，based on the analysis results，the methods and suggestions to improve the gear walking vibration of landing gear are given.

The shock signals in the process of road transportation cause the non-Gaussian characteristics of random vibration process. In order to study the impact of shock on product damage，the measured 8 vibration signals of medium truck and heavy truck are statistically analyzed. The vibration signals are divided into 20% high-intensity non-Gaussian signal，60% medium-intensity Gaussian signal and 20% low-intensity Gaussian signal. The finite element software is used for time-domain vibration analysis to calculate the damage proportion of each signal segment. The results show that the non-Gaussian signal contains high intensity shock signal，which causes the most of damage. The shock amplitude of medium truck vibration data is large and accounts for a small proportion，while the shock amplitude of heavy truck is relatively low and accounts for a large proportion. The higher 5% shock signal for medium trucks caused more than 90% of the damage； The 20% non-Gaussian signal of heavy truck contains 10% higher amplitude vibration besides 10% shock component，and the damage caused by 20% non-Gaussian signal is about 80% or higher. In the whole transport vibration process，the shock signal dominates the accumulation of damage with less content.

In order to explore the influence of the traction motor distribution on the dynamic characteristics of rack vehicle and gear-rack meshing characteristics，the vehicle dynamics characteristics under different traction motor layout modes are analyzed with the consideration of the gear-rack nonlinear meshing behavior and dynamic time-varying excitation and the wheel-rail nonlinear contact relationship. Based on the Strub system，the coupling dynamics model of rack vehicles is established. The influence of three different motor forms on the dynamic characteristics is studied. On this basis，the layout mode suitable for rack vehicles is proposed.The research shows the gear meshing force and the vertical and longitudinal vibration acceleration are smaller under the dual-mounted traction motor conditions. When the motor is dual-mounted，the meshing force is about 50% of that the motor is rear-mounted and front-mounted. The maximum amplitude difference of the vertical and longitudinal acceleration of the gear is 4.04 m·s^-2 and 6.01 m·s^-2 in the straight section. When the motor is rear-mounted the gear vibration acceleration is the largest，and the vertical and longitudinal acceleration amplitudes are 45% larger than the dual-mounted traction motor conditions in the climbing section. The comfort of rack vehicle is better when the motor rear and front-mounted on the straight line，but the dual-mounted is better in the climbing section. In view of the fact that rack vehicle is mainly used in climbing lines，and the dynamic characteristics of rack vehicle with dual-mounted are the best when climbing. Thus，it is recommended that the dual-mounted is the optimal layout mode.