Currently, only lateral-horizontal seismic load is considered in seismic response analysis of underground structure, and the seismic loads in longitudinal-horizontal direction and vertical direction are usually neglected. In this paper, an underground structure, whose length was much larger than the width, was considered. The three-dimensional model for finite element analysis was established and its dynamic responses under lateral, longitudinal and vertical seismic loads were analyzed respectively. The results show that it is not enough to consider lateral horizontal seismic load only for this type of underground structure. The results provide a reference for anti-seismic design of underground structures.

The relation between train door’s modes and transient pressure wave for high-speed train’s crossing is discussed. The basic theory on mode test is introduced. The basic mode of a single train’s door was obtained by hammering-impulse excitation. The developing mode of train’s door-frame system was obtained by sinusoidal frequency-scanning excitation. Combining the basic mode and the developing mode of the train’s door, its frequencies and modes of bending and torsional vibrations can be understood. With the improvement of the mode’s parameters of the train’s door, the effect of transient pressure wave in the high-speed train’s crossing can be reduced and relaxed.

In this paper non-linear finite element method was introduced to simulate the environmental test of a set of rubber-structured absorber, which is used in aerospace. At first the stress-strain curve of silicone rubber and corresponding hyperelastic model were created by material experiment. To simulate the sinusoidal vibration test, Incremental Analysis was used for the frequency response analysis of the absorber considering behavior of large deformation of silicone rubber material, and boundary conditions were determined according to the amplitude and frequency of vibration test system. The appropriate error between the simulation result and vibration test proves that application of non-linear FEM is available to perform simulation of complicated process.

In this paper, some measures for ensuring the effect of inspecting vehicle suspension parameters by the quasiimpulse excitation are proposed. They are the excitation with press bodywork; the plate inspecting; the calculation of suspension parameters; adopting the criterion of the correlated dimension D2; recognizing the periodicity of samples with maximal Lyapunov index λmax; and selecting the maximum/submaximum values in the samples to compute the dampingratio ξ. With these measures, the parameters of the suspension systems of two testing automobiles are inspected. And the results show that the measures introduced in this paper are feasible.

The commonly used domestic and foreign decoupling methods are introduced. A model of powertrain mounting system with six degrees of freedom is established. Aiming at the vibration problem of some passenger cars, a test and a vibrationisolation performance analysis of the original mounting system are carried out. Taking the stiffness and installangle of the mounts as variables, improvement of design is done based on the energy decoupling theories to improve vibrationisolation performance of the mounting system. The vibration test of the entire vehicles mounting system is done, and the testing data before and after the improvement of the system is compared. It is proved that the improved design is effective and rational.

By means of vibration and noise experiments for a pad made of steelfree fiber reinforced frictional material, the damping coefficient and other factors, which impact the vibration and noise of the pad induced by braking, are studied in both frequency domain and time domain. Through the comparative analysis of vibration and the noise signals, the relationship of vibration and noise is investigated. In addition, the mechanism of vibration and noise of the brake pad is discussed. Some effective control approaches are suggested. The results may provide some references for further study on this material for vibration and noise reduction.