In order to supply a gap of current resonance vibration and STFT demodulation method applied to rolling bearing fault feature extraction of city rail vehicle, a fault diagnosis method for rolling bearing is presented, which is based on the integration of improved wavelet packet, frequency energy analysis and Hilbert marginal spectrum. When faults occur in rolling bearing, the energy of the roll...

In this paper, a theoretical study is conducted in order to establish the feasibility of a liquid metal acoustic resonator ͑liquid gallium or liquid aluminum͒ for high-amplitude acoustic oscillations. The fundamental resonant frequency typically lies between 5 and 40 kHz. The oscillations are induced by an alternating Lorentz force density applied directly to the liquid metal volume. Depending on...

Results of an experimental investigation of the seismic performance of prefabricated column-footing connections are presented. Tests were conducted on six 1/4-scale prefabricated column specimens inserted into prefabricated footings in two Groups. Group-1 consisted of four specimens, which were tested under constant axial load and cyclic inelastic lateral displacements. The remaining two specim...

In order to grasp the nonlinear experimental errors of dynamic shear modulus ratio (DSMR) and damping (DR), as well current level resonant column testing, GZ-1 instrument was used study probability statistical indicators, basic laws, impact on peak acceleration DSMR DR silt under 8 typical strains. The results show that, firstly, different strains obey normal distributions. Secondly, there is n...

Association field models have attempted to explain human contour grouping performance, and to explain the mean frequency of long-range horizontal connections across cortical columns in V1. However, association fields only depend on the pairwise statistics of edges in natural scenes. We develop a spectral test of the sufficiency of pairwise statistics and show there is significant higher order s...

multi frequency vibrations of a system of two isotropic circular plates interconnected by a rolling visco-elastic layer that has nonlinear characteristics are considered. the system with two circular plates and interconnecting discrete continually distributed rolling visco nonlinear elastic rheological elements presents the model of hybrid nonlinear system. the analytical solutions of first asy...