Since the fault vibration data collected in the real engineering may be accompanied by noise, traditional diagnostic models are difficult to identify fault categories. To address this problem, a rolling bearing fault diagnosis research method based on channel and spatial reconstruction and progressive convolutional neural networks (CSRP-CNN) was proposed.The model utilized channel and spatial reconstruction convolution（CSConv）to reduce the redundant information of channels and space in fault features, and reduced the complexity and computation to improve the performance; using the convolutional block attention module (CBAM), attention enhancement operation was carried out in the channel and spatial dimensions to make the model pay attention to the important fault feature information; and the progressive convolutional network structure was used in the shallow layer of the network, which would fuse the previous fault feature information with the current input to obtain the richer feature information. The performance of CSRP-CNN was evaluated by two different datasets of Case Western Reserve University (CWRU) and machinery fault simulator magnum (MFS-MG). After the noise and ablation tests, it is verified that CSRP-CNN has strong robustness and the effects of CSConv, CBAM and progressive convolutional neural network (PCNN) on the model noise immunity performance.

In order to study the dynamic behavior of stiffened cylindrical shells with composite material sandwiched by co-cured damping films under the clamped boundary condition, the specimens of stiffened cylindrical shell with composite material sandwiched by co-cured damping films were prepared, and the dynamic modal test platform was set up. The fundamental frequency, damping ratio and modal shapes of stiffened cylindrical shell specimens were solved, and the accuracy of finite element model was verified. The influence of geometric parameters on structural vibration characteristics was further discussed by the numerical simulation method. The results show that, the fundamental frequency, damping ratio and modal shape of the structure will change abruptly when the height of stiffeners changes, and there is a suitable height value before the abrupt change to make the whole structure consider both damping and stiffness requirements; when the thickness of composite materials is constant, the fundamental frequency of the whole structure decreases gradually and the damping ratio increases gradually with the increase of the damping thickness or damping layer number of single layer; for the stiffened cylindrical shell of single layer damping composite materials, the closer the damping layer is to the inner skin, the higher the stiffness is, and vice versa, the damping capacity is better.

The noise of automotive electronic water pump (EWP) is an important indicator of the performance of EWP,and its active control is conducive to improve the sound quality of the car. In order to achieve the active control of the noise of EWP, a hybrid random carrier space vector pulse width modulation (HRCSVPWM) strategy was proposed. Firstly, the Xorshift algorithm was used to design a random sequence generator to generate random numbers with good randomness to disperse a large number of harmonics concentrated in the carrier frequency and its integer multiples. Secondly, the sawtooth wave period function was combined to increase the weakening effect on the pulse width modulation (PWM) harmonic amplitude. Then, the simulation model of the EWP was constructed to investigate the harmonic suppression effects of control strategies of space vector pulse width modulation (SVPWM), random carrier space vector pulse width modulation (RCSVPWM) and HRCSVPWM, to verify the ability of HRCSVPWM to suppress PWM harmonics. Finally, EWP noise test platform was constructed to analyses the noise of EWP under three types of control strategies.The results show that the noise suppression effect of HRCSVPWM is remarkable, which can make the noise’s sound pressure level of EWP decrease significantly, with an average decrease of about 3 dB.

In order to reveal the nonlinear dynamics behavior of the marine rotor-bearing system under complex transport motions (heaving, swaying, yawing and pitching), the dynamical model of the rotor-bearing system with the nonlinear oil film force and transport inertial forces was built based on, Lagrange’s equation.The effects of the rotating speed and transport motion parameters on the nonlinear dynamics behaviors of the system were mainly analyzed. The results show that the amplitude and oil film whirl interval of the system are larger when considering the coupling motion of heaving, swaying,yawing and pitching than those when not considering this motion. Affected by the coupled transport motion, the rotor will deflect obviously at a lower speed. At a certain rotational speed, with the increase of heaving amplitude, swaying frequency or swaying amplitude, the amplitude jump phenomenon caused by the oil whirl appears in the vibration response of the system，and the motion state of the system undergoes quasi-periodic and chaos. With the increase of swaying frequency, yawing amplitude, yawing frequency, pitching amplitude or pitching frequency, the system is always in a quasi-periodic vibration state,but the vibration amplitude of the rotor increases in varying degrees.

Limited by the vibrator structure, there are some problems such as low down-going earth energy and shallow down-going depth of shear-wave signals when the shear-wave vibroseis is excited. Therefore, the influence of different combinations of shear-wave vibroseis vibrators on the excitation effect was innovatively studied through the three-dimensional finite element numerical simulation. Firstly, based on three-dimensional nine-component data and two types of combinations,eight modes of vibration excitation of combined shear-wave vibroseis were considered, a vibrator-earth finite element model was established, and an evaluation system of the vibration excitation effect of the combined shear-wave vibroseis was constructed. Secondly, based on this evaluation system, the influence of the various combined excitation modes of the shear-wave vibroseis on the downward energy of the earth, the downward depth of shear-wave signals and the mutual interference between combined excitation waves was analyzed in detail. The results show that, compared with a single shear-wave vibroseis, when two SHY shear-wave vibroseises are arranged side by side for the normal excitation, the incoming earth energy is increased by 86.36%, and the displacement amplitude of earth particles is increased by 73.40% on average. When two SHX shear-wave vibroseises are excited in the normal direction, the incoming earth energy increases by 97.48%, and the displacement amplitude of earth particles increases by 58.61% on average, which greatly improves the excitation effect. The research results can provide the guidance for improving the excitation effect of the shear-wave vibroseis and the reference for the design of combined excitation mode of the shear-wave vibroseis.

Abnormal vibration in the pipeline associated with large synchronous condensers not only reduces the lifespan of the pipeline but also affects the supply of the lubricating oil and coolant for the synchronous condenser, posing a serious risk of major safety accidents and jeopardizing the stability of the power system. The lubricating oil supply pipeline of a specific ultra-high voltage converter station synchronous condenser was taken as the research object. Multiple methods, including field measurements, fluid-structure coupling, and harmonic response analysis, were used to investigate the causes and mechanisms of the pipeline vibration. The results indicate that the periodic excitation force generated by the synchronous condenser itself is the main cause of pipeline vibration. Furthermore, a pipeline vibration reduction measure based on a tuned mass damper(TMD) was proposed. Experimental and simulation data shows that installing a TMD at the intermediate positions between suspension supports 4 and 5, as well as 6 and 7 in the lubricating oil supply pipeline system, yields the best vibration reduction effect. This approach can reduce the vibration acceleration of the pipeline system by over 90% and exhibits the excellent vibration reduction performance.

Aiming at the noise problem of the automobile electric seat adjuster, a pair of modified worm and modified helical gear was adopted for its main transmission system to reduce the meshing impact. The mathematical model was established, and several worms and helical gears with different modifications were processed. The noise test bench was built,and the acceleration spectrum of the automobile seat adjuster under the original models and different modifications were tested. Then the whole device’s noise reduction test was conducted with the optimized combination of tooth profile modification. The analysis results show that the appropriate profile modification of the worm and helical gear can effectively reduce the acceleration spectrum peak. With 0.04 mm and 0.02 mm modification respectively for the helical gear and the worm, the acceleration peak value of seat adjuster is significantly lower than that of the original product. The difference between the 6 sets of test products maximum noise and the standard products is within 1.6 dB, and the acceleration spectrum and acceleration peak of the experimental products are significantly reduced compared to the original product, which can verify noise reduction by the tooth profile modification of worm and helical gear pair is feasible.

An improved northern goshawk optimization (INGO) algorithm was proposed to address the local optimization problem that swarm intelligence algorithms often encounter when optimizing support vector machine (SVM) models, and it was applied to fault diagnosis of rolling bearings. By introducing an adaptive inertia weight factor based on the cosine variation and a Cauchy mutation strategy, the northern goshawk optimization (NGO) algorithm was improved, and an INGO-SVM fault diagnosis model was constructed using SVM. In order to evaluate the performance of the improved algorithm,firstly, benchmark testing functions were used for experiments, and the improved algorithm was compared with existing optimization algorithms such as NGO, particle swarm optimization (PSO), sparrow search algorithm (SSA), etc. The results show that the performance of the improved algorithm is improved to a certain extent. At the same time, the original diagnostic signals were feature extracted through wavelet packet decomposition and divided into 10 categories. The energy of each frequency band in the 3rd layer was used as the feature vector and input into the fault diagnosis model. Finally, the performance of the improved algorithm was compared with the other three algorithms in optimizing SVM parameters for fault classification. The results show that the improved algorithm can effectively and accurately achieve different fault classifications, with an accuracy rate of 99.39%, verifying the effectiveness and feasibility of this method.

Single tube towers are widely used as the foundation for carrying 5G communication equipments. Due to construction needs, the mounted equipments often changes with the changes in 5G construction. Due to the small damping of the single tube tower, the increase of mounted equipments may cause an excessive vibration, reducing its load capacity.Therefore, the control of tower top vibration is particularly crucial. A particle damping tuned mass damper (PDTMD) method was proposed to control the problem of excessive vibration at the top of 5G communication towers. Based on a collision theory, a mathematical model using PDTMD to control the vibration of the communication tower was established. The vibration response of the tower under effects of PDTM was verified by the detailed calculation, and the damping mechanism of PDTMD was analyzed. The damping effectiveness of PDTMD was compared with the traditional tuned mass damper (TMD).The results show that the particle damping has good energy dissipation ability. Compared with traditional tuned mass dampers,PDTMD has better damping effect and higher robustness. Finally, based on the actual signal tower, the usage parameters of PDTMD in complex environments were optimized. Effects of gaps between damping particles and honeycomb structures,particle materials, and particle mass ratios on the damping effect of dampers were analyzed.

To achieve quantitative detection of bolt loosening angles through single frame images, a method based on color segmentation and connected domain feature processing was designed. Firstly, a method for performing nonlinear stretching, normalization and optimal threshold segmentation on a component successively in the Lab color space was designed to segment and represent the red anti-loosening line image of the bolt loosening angle. Secondly, the morphological operations were performed on the image by using the open operation. Then, the orientation vector of the connected domain in the anti-loose line image was determined by computing the geometric moments. Finally, the bolt loosening angle was determined through the four-quadrant arctangent function. The results demonstrate that the precise measurement of the bolt loosening angle through a single frame image can be achieved by this detection algorithm, with a maximal relative error of 1.80%, its accuracy meets the needs of engineering practice and has strong engineering application value.