Key Engineering Materials Vols. 353-358

Abstract: With elastic theory and approximate calculation, the dynamic responses of elastic thin plates with four edges simply supported under blast loading is analyzed in this paper , with dimensional analysis , 30 cases are calculated, and a reasonable model of engineering calculation is built up in the end.

Abstract: As the public application of the railway and the road increases, properly functioning and safe railway crossing between two means of transportation becomes more important. In the past, materials such as wood, asphalt, and steel were used for railway crossing panel. As these materials showed various drawbacks, the rubber panel was introduced for railway crossing panel. To encourage the use of the rubber panel, the structural action analyses of rubber panel were studied. In this research, using the finite-element method (FEM), several structural properties were analyzed and presented including the eigenvalue, stress, and displacement by a passing truck’s weight, and the thermal stress induced by the railway track.

Abstract: Distance evaluation and its improved algorithms using Vertical distance instead of Euclidean distance were discussed in engineering materials selection. Taking the selection of materials for low temperature storage container as an example, based on eight kinds of evaluation indices, according to the weight obtained by AHP method, ten kinds of candidate materials were evaluated by using distance evaluation and its improved algorithms. The results indicate that, the optimal material selected coincides with the practice of industry, and the sequence of the candidate materials arranged using improved algorithms is more reliable, which shows that improved algorithms of distance evaluation is a feasible and effective way for engineering materials selection.

Abstract: Aiming at the concentric shaft of the abnormal cross-section where there are two types of the concave fillet and the convex fillet and whose diameter ratio is bigger than 2, a 3D finite element computing model was constructed, and the stress and the strain is computed by means of software ANSYS8.0, and a stress concentration coefficient graph is found through comparing the result computed by FEM and by the method of material mechanics. It is concluded that the most important factors effecting the stress concentration are the type and radius of the transition fillet.

Abstract: In order to investigate performance characteristics of deteriorated subway rolling stocks, several engineering assessment methods, such as the acceleration, vibration, and braking performance tests, were carried out on subway electric multiple units (EMUs) with over 20 years operation. According to the testing results, in vibration and braking performance of EMUs, the similar performance results were obtained as compared with newly manufactured EMUs. However, in terms of acceleration performance characteristic, below reference value (3.0 km/h/s) has been obtained. This is mainly due to performance deterioration of EMUs including traction motor. In this investigation, the results on precision diagnosis evaluation of deteriorated EMUs were provided through the overall evaluation of corrosion testing and structural performance of car body in subway EMUs.

Abstract: Based on neural networks, the present paper gives an engineering application of data mining. The back propagation (BP) neural network is used as the algorithm of data mining. Then the effects of structural technologic parameters on stress in the weld region of the shield engine rotor in a submarine are analyzed. The mined data come from the numerical simulations of the finite element method. The effects of different parameters on the stress in the weld region are achieved from the results of the data mining. The discovered knowledge is beneficial to the security improvement of structural strength design for the engine rotor.

Abstract: The metallic films covering diamond play a very important role in the course of diamond nucleation and growth from Fe-Ni-C system at high-temperature and high-pressure (HTHP). The microstructures and surface morphologies of the metallic films are investigated by field-emission scanning electron microscope (FESEM) in this paper. It is shown that there are large numbers of small particles and a series of serrations on the inner surface of the films. It is calculated that the metallic film is mainly composed of (Fe, Ni) 3C, (Fe, Ni)2 3C6, but no diamond structure. The results by energy dispersive spectrometer (EDS) analysis are in good agreement with these by transmission electron microscopy (TEM). It can be concluded that the carbon atom groups coming from the decomposition of Fe-C compound rich in carbon in the film are deposited on the diamond surface directly and diamonds grow in the model of sandwich.

Abstract: This paper presents a novel bulk micromachined gyroscope with the compensatory capacitance. Independent driving and sensing beams and a dual-frame structure are adopted to decouple mechanically for stable operation. The method of electrostatic push-pull drive and capacitive sense combs based on the slide film damping are applied to obtain a large driving force and high quality factors. The compensatory capacitance is designed to compensate the deviations of sensing differential capacitance from fabrications. The designed gyroscope has matched resonant frequencies of 2187Hz and 2206Hz for the drive and sense modes, respectively. Considering the noise of interface circuits, the gyroscope system sensitivity can reach 14.2mv/o/s, theoretically.

Abstract: The thickness of the process equipment increases in proportion to pressure for the methane hydrate transportation and storage. The pressure is one of the most important factors, because a material must be selected in the way of proper pressure and temperature to design the process equipment. Therefore, we tried to figure out whether the phase equilibrium temperature & pressure can be applied to the designed temperature and pressure or not, and carried out the thickness calculation of the pure methane hydrate container in accordance with “Boiler and Pressure Vessel Code - Division I of Section VIII, ASME”. Also, we studied on the effect of the container’s thickness using the results of the phase equilibrium temperature and pressure measurement including the inhibitor and promoter of the methane hydrate on some related references.

Abstract: Efficient methods are described here to predict the fatigue damage of ship structure due to nonlinear wave loads that are produced in random seas. Firstly the effects of the non-linear waveinduced bending moment on the fatigue damage of ship structure with very large bow flare are presented in short-term prediction by the method of spectrum analysis. Then, the fatigue damage is estimated and analyzed in the given environment of long-term.