The dynamic crush behavior of an anti-shock layer with elastic foundation was investigated. Considering the hyperelastic and viscoelastic behavior of the material, the shock resistance capacity of the anti-shock layer was analyzed. Influence of the structure parameters, such as relative density, edge length and topological shape, on the anti-shock performance of the layer was studied. It was found that in low frequency range the shock spectrum is lower when the relative density and the edge length of the layer are smaller, and round hole is the best choice for the anti-shock layer. While in high and middle frequency range, the anti-symmetric honeycomb structures have the best dynamic performance. On the base of the analysis, the optimization design, called anti-shock double-layer structure, has been provided, which has excellent dynamic performance compared to the traditional anti-shock layer.

Aiming at the problem of car-body optimization, the frequency response sensitivity analysis is used to reduce the response displacement of the car-body structure. Based on the finite element model of the car-body，the frequency response is calculated，and the displacement response curve of driver’s seat bracket is obtained，from which the vibration peak for a given frequency is found. To reduce the vibration peak, an optimal design based on the frequency response sensitivity analysis is carried out by selecting the appropriate design parameters. After the optimization，the response displacement?at key frequencies of the car is obviously reduced，and the riding comfort of the car is improved.

Thrust bearing is one of the most important components which affect the coupled vibration of the shafting-hull coupled structure. Its impedance characteristics affect the transmission characteristics of the longitudinal oscillatory force from the propeller to the hull structure directly. So, the thrust bearing’s oil film stiffness in the ship propulsion system has a critical influence on the coupled vibration of the shafting-ship hull structure. The thrust bearing’s dynamic characteristics have been investigated in this paper and the thrust bearing’s oil film stiffness at different propulsion speeds is obtained, which is further applied to the dynamic model of the shafting-hull structure. The coupled vibration of the shafting-hull structure at different propulsion speeds is analyzed. The results show that the thrust bearing’s oil film stiffness at the low and medium propulsion speeds is the leading factor that affects the transmission of the longitudinal oscillatory force from the propeller to the hull structure, hence it must be considered in the prediction and control of the hull-structure’s vibration and acoustic radiation induced by the longitudinal oscillatory force.

For the non-stationary and modulation features of rolling bearing’s fault signals, a method based on wavelet analysis is employed. The signals including fault information are decomposed and reconstructed by wavelet analysis method. Then, demodulation and fine spectral analysis of the signals are carried out by using Hilbert transform. The characteristic frequencies of the fault signals are extracted, and the fault patterns of the rolling bearings can be recognized. It is found that the wavelet analysis and Hilbert transform are effective in identifying the local defects of rolling bearings.

Protection of shipboard personnel from shock events induced by underwater explosion is very interesting to ship designers. In this study, the potential attenuation performance of an elastic polymer foam cushion inserted between standing-man and ship deck is investigated theoretically. An 8-DOF nonlinear lumped-parameter model is used to predict the standing-man’s biodynamic responses and injury potential. The cushion is modeled by a chain of masses separated by nonlinear springs and dampers in parallel to simulate the micro inertia, stiffness and rate-dependent effects exhibited by common polymer cellular materials. Two variables, kickoff speed (KS) ratio and deck reaction force (DRF) ratio corresponding to two types of typical injury potential of standing-men, are defined as evaluation parameters. The influence of critical buckling force level, material rate dependent effect as well as other design factors on the attenuation performance of the foam cushion is discussed in detail. Some general design rules are also presented.

It is effective to reduce vibration of a ship stern that vibration isolation on the dominant transmission path. The transmission paths model of a ship stern was built based on the ship stern structure. When excited longitudinally at the propeller, the transmission paths of stern is analyzed and sequenced by the transmission paths analysis method. The results show that the palace at bearing basement is a dominant path when excited longitudinally. Thus, when the dominant transmission path is identified, passive control or structural modifications on the path can attenuate vibration levels effectively. The numerical results explain that the acoustic radiations of the structure can reduced by modification of the bearings rigidities and of bearing basement configuration.