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A new method is proposed to identify structural damages based on the power spectral density sensitivity analysis. The responses of the structure under stationary and random excitations are obtained using pseudo excitation method, and then the sensitivities of power spectral density with respect to the structural damage parameters are obtained similarly. Finite element model updating method is adopted to identify the structural damages. A numerical example of a shearing structure demonstrates the satisfactory results obtained from the present method.

A multi-body dynamics model and ground model of a small crawler chassis was built on software RecurDyn/Track (LM). The simulations of the small crawler chassis turning on hard and soft terrain are implemented respectively, and the results are analyzed and compared. The steering properties of crawler chassis turning on soft terrain are emphasized. The simulation results can provide some theoretical guidance for crawler chassis steering performance.

The correct identification of GIS partial discharge type is essential for assessing the insulation status of GIS and developing a reasonable maintenance strategy. After the analysis of the intelligent diagnosis system design, the software architecture of host and remote computer is given by this article. Site host computer completes the data preprocessing and the remote host computer completes the function of real-time observation, data storage and inquiry, spectrum analysis and pattern recognition. The test shows that the software can complete the intelligent recognition of partial discharge.

The failure of the underframe is one of the most important factors affecting the service life of the multi-function chassis. This paper established a virtual model of multi-function chassis by UGNX 3D software; The use of the finite element analyzed model, find the weak link of underframe, and effectively reduce the underframe weight, determine the optimal scheme. Based on the underframe structure design to create the underframe prototype, and passed the test to prove the prototype running smoothly, safe and reliable.

The combustion channel of compact methane reformer includes fuel flow duct, porous layer and solid connector. There are heat transport and multi-component species diffusion/convection processes in porous structure. The transfer processes are coupled with methane catalytic combustion, and affect the performance and stability of reformer. A 3D in-house code has been developed to simulate the mass and heat transfer processes involving chemical reactions in the reformer channel in specific condition (mass fraction of CH4YCH4is less than 1% in the mixture of methane and air). It shows that, catalytic combustion reactions mainly tack place on the porous layer near inlet with a higher temperature area, the biggest heat flux region from the bottom wall is found near the higher temperature area. The reaction rate of methane, temperature of porous layer and heat flux increase with the increase of YCH4. In general, 0.4% is an adequate value for YCH4. The research has a benefit meaning to provide a guideline for the improvement and design for compact methane reformer.

A large amount of drilling pump vibration signals are acquired and decomposed optimally into time-frequency atoms by the Pattern Filter Method. All of these time-frequency atoms are falling into the multidimensional statistical cube which is formed by the time-frequency atomic parameter (α,f,φ,A) space with certain interval length. The atoms in every cube are counted and the results are stored in a database. When keeping any two parameters in a certain range, the quantitative distribution contour maps in the plane of other two parameters are demonstrated by the Graf software tool, then all sub-space results were aggregated to construct the macro-views of the BOU quantity distribution in the four-dimensional space ,meanwhile the quantitative distribution of these atoms are investigated, the distribution characteristics for various vibration signals of drilling pump are obtained and all atoms are classified according to their clustering state in this parametric space. Furthermore, every special signal corresponding to the parametric feature clustering of atoms in this multidimensional space have been identified. The desired results have been achieved in signal identification and drilling pump fault diagnosis by use of these consequences.

In this paper, we investigated the structure of SmCo films with different thickness and the effects of Cr buffer layer on the structure and morphology of SmCo/Cu thin films. Our data revealed that the magnetic properties of the samples were enhanced by the crystallization of SmCo which was promoted by the optimized Cu underlayers. We also found that the surface roughness can be decreased by Cr layer and the texture can be improved by prolonging the annealing time for thick SmCo film. Thus, we concluded that the magnetic properties of SmCo/Cu films can be further optimized by varying the thickness of Cr buffer layers.

The composite element method is utilized to discretise a stepped Euler-Bernoulli beam with a crack. The local stiffness reduction due to the crack is introduced by using a simplified crack model. The finite element equation for the forced vibration analysis is obtained using the composite element method (CEM). The forced vibration response of the cracked stepped beam is numerically calculated using Newmark integration method. Numerical results indicate that the position and depth of a crack affects the low and high natural frequencies and modes of a cantilever beam, respectively. And the position of the crack has significant effects on the dynamic responses of the beam.

Magnesium alloys are potential in biomedical materials, but their corrosion rates are high in human body fluid so that they can not be used enough time. Therefore, to improve the anti-corrosion property of the alloys is important for their application in biomedical materials. In the work, a new coating was prepared from poly (3-hydroxybutyrate) (PHB), a biopolymer used as a sustained release carrier of drugs. The effect of the PHB coating was studied by electrochemical tests, scanning electron microscope (SEM) and weight loss corresponding with the corrosion time. The result showed the sample coating PHB have a higher corrosion potential than one before coating PHB, that is, PHB coating is effective for improvement of corrosion resistant of the alloy. Moreover, the corrosion state on the surface is even by SEM, implied the corrosion rate of the PHB coating is divinable and controllable. Whereby, PHB should be suitable for anti-corrosion of magnesium alloys applying in biomedical materials.