In order to reduce lateral vibration of high-speed strain, the dynamics model for semi-active suspensions of vehicles was established in ADAMS/Rail code. Programs for genetic algorithm procedures were written in MATLAB code using a mixed encoding method of float and decimal numbers, and the method of adaptive genetic crossover and mutation probability based on standard deviation of fitness values. The membership functions, fuzzy rules, quantification factors and scaling factors were optimized. Using the RMS of lateral vibration at the front and the rear of the vehicle’s body as the performance index of the genetic algorithm, the fuzzy controller of the semi-active suspension was constantly optimized. The joint simulation results show that using GA-optimized fuzzy semi-active suspension can effectively reduce the lateral vibrations and improve the ride comfort of vehicles.

The vibration and noise sources and their diffusing routes of ships are described and analyzed. The standard and method for control of noise and vibration of ships are introduced. The noise level of ship’s AFT is analyzed by VA ONE, and the result of noise and vibration are obtained by means of statistical energy analysis (SEA). It is found that the results are in good agreement with the measurement data in shake-down voyage.

The method of Moving Detrended Fluctuation Analysis (MDFA) is studied, and the scaling exponent of the signal time sequence is obtained. It is found that the scaling exponent fluctuates greatly at the signal mutation point, while it fluctuates slightly in the trouble-free places. Thus, MDFA method can be used to detect the mutations in engineering signals. In this paper, the MDFA method is applied to the simulation of the signals due to mutation faults in gears and bearings, and the results show that the MDFA method is effective in mutations fault diagnosis of rotary machines.

How much can weather conditions influence the effectiveness of automatic monitoring of noise? And is it necessary to carry on synchronous meteorological monitoring for the noise automatic monitoring? In order to answer these questions, a deep analysis is required. Based on the monitoring data and related information, the correlation between sound level and wind speed is analyzed. The results indicate that wind speed should be measured simultaneously in noise automatic monitoring to ensure the reasonableness and accuracy of the data. The noise monitoring data must be modified or validated according to wind speed monitoring data.

An MRFD force model is established for damper force characteristic investigation through theoretical analysis. Force characteristic of MRFD was studied experimentally in self-made testing equipment. The relationships between force and displacement, force and current, force and velocity were tested. The damper force of MRFD for a given velocity is predicted by the theoretical model. The experiment results show that the theoretical model and the experimental data are in agreement, and the damping coefficient can reach 3.5.

Piezoelectric sensors or actuators are bonded to the surfaces of a flexible cantilever beam. The finite element method is used to build the model of the beam. The dynamic response data of the piezoelectric smart structures is obtained through the FEM analysis. According to the nonlinear approximation capability of neural networks, a dynamic recursive BP neural network is used to identify the piezoelectric vibration system, and the predictive model is built. On the basis of the neural network predictive model, the generalized predictive control algorithm is proposed to control the piezoelectric vibration system and to suppress the undesired vibration of the structures. Simulation results demonstrate the excellent performance of the developed control system. It has some significance for guiding the application of intelligent control algorithms in smart structures.

The phenomenon of irregular wave output of crystal oscillator in the random vibration test is studied in this paper. Using the resonance free technique and the knowledge of flat spring, the dimensions of the flat spring are determined; the flat spring is installed and tested; and the problems in the testing is resolved.

A traditional lumpedmass model for the boom shipmounted crane is established in this paper. The nonlinear dynamic equation is presented using the EulerLagrange method. Then the nonlinear dynamic behavior of the cable is analyzed numerically, and the impact of some key parameters on the cargo pendulum is studied. Results of this study are of significance for the operation of shipmounted cranes.

Engine room’s noise is the main noise source. The noise signal of the engine room of a military ship is measured and its spectrum is analyzed. The main radiation frequency of the noise is found. The contribution of reverberation sound to engine room noise is studied. The scheme for reverberation sound control is worked out, in which a new damping soundabsorption material, the melamine foam, is utilized. Based on the statistical energy analysis (SEA), the geometrical model, the physical model and the mathematical model of the engine room are established. The software for simulating sound absorption of the engine room is made. According to the scheme of design, the melamineformaldehyde?foam coating is equipped in the engine room and then the noise testing is carried out. Result shows that the noise of the engine room is reduced 5.6dB(A).