Applied Mechanics and Materials Vols. 80-81

Abstract: In order to improve detection efficiency of casting bolster and side frame of railway freight car, the method to automatically detect railway casting porosity and shrinkage cavity using watershed transformation based on X-ray digital radiography is presented. Firstly, while castings of a bolster and a side frame are scanned by 9Mev X-ray digital radiography system, the DR images are obtained. Then one of interested regions is selected in an image. Defects segmentation is implemented by using watershed transformation algorithm in this paper. Lastly, defects area and occupy rate are acquired by analyzing and computing, so that we can judge the casting quality. The experimental results show that defect regions and contours can be accurately acquired. This method has high robustness and practicality. It improves the efficiency of automated inspection of railway castings.

Abstract: According to the “Ultimate strength design methods” of rolling bearing and from the whole strength of ring, the paper has analyzed the relationship between ring deformation and strength. It is shown that the local deformation of ring is the main factors affecting the collar strength. Programmed Matlab procedures, the minimum limit of ring thickness of the driving wheel bearing is studied, and a reasonable explanation of outer-ring fracture is given.

Abstract: Investment casting method can fabricate the impeller slots with non-uniform thickness and distorted surface. The process of investment casting can be simulated by employing ProCAST software. The mesh of the casting was introduced in the article. The influence about the initial temperature of shell on the defects of the casting and the pouring temperature and the pouring speed on the effective stress of the casting was studied in this article. When the initial temperature of shell was 400°C,there was no defect in the casting. The pouring temperature of the casting, will produce a very strong influence on the effective stress. When the pouring temperature in this article was 800°C, the maximum effective stress of the casting was 108MPa.

Abstract: This paper try to analyze the rheological behavior during the wax injection, and build a mathematical model to simulate the wax injection process. By using Moldflow, simulate a wax pattern with different ingate configurations to optimize the injection modeling product design. This study helps to improve the model design quality, shorten the development cycles, lower down the overall cost and enhanced competition in market.

Abstract: Based on assumptions and tests of the discharge temperatures land pressures for a scroll compressor, a simulation of radial deformations of the orbiting scroll wrap is performed. All simulations show that the radial deformation of scroll wrap varies complicatedly in outer part. Although the deformations are controlled by the temperature of scroll wrap, the inner pressures of scroll wrap can make the radial deformation more uniform. So reducing temperature difference between the discharge and suction temperatures, using the material with lower thermal expansion coefficient are several effective means to improve the performance of scroll compressor in engineering practice.

Abstract: Basing on material mechaanics and the finte element method,the interrelated analysis modules of Pro/E-MECHANICAL is used to analysis the stress and distortion of the coiler mandrel,getting the weakness of the coiler mandrel and getting the location of the maximum stress and the relationship between steel rolling external diameter and stress distortion, Obtaining the maximum stress is 82.8 Ma,the maximum displacement is 0.56 mm and getting the main reason for coiler mandrel published.Basing on the finite element analysis to improve its structure, to make its service life prolong greatly.

Abstract: With the rapid development of plastic products in the world and the increasingly sophistication of plastic technology, rotational moulding (RM), has become the most practical and irreplaceable way of producing the large and super large containers like tanks, tank, etc. Compared with injection moulding and blow moulding, RM has the characteristics of low cost and easy-to-use, and its application has been extended into many domains. The principle of rotational moulding and comparison of raw material by the requirement of rotational moulding is introduced. The paper emphasizes the introduction of state-of-the-art of RM equipment; also it points out the development of RM.

Abstract: DVG850 high-speed machining center worktable is taken as research object, in order to meet the overall performance requirements of the high-speed machining center, 3D model of worktable is established in SolidWorks. Static analysis and modal analysis are carried out in ANSYS Workbench, and then the worktable is optimized in topology optimization module of ANSYS Workbench. According with the analysis results, the worktable structure has improved. The improved worktable keeps the original’s static performance, and enhances the dynamic performance; however, its quality is lighter than original structure by 23.2 kg.

Abstract: This paper reports the fabrication of a tunable radio-frequency (RF) inductor and discusses the parameters that influence the quality factor (Q) of the inductor. The influence of the thickness of the metal layer on Q is mainly emphasized when other parameters are fixed. In the process of the fabrication, SU-8 is used as photoresist instead of the traditional photoresist. This paper aims to get higher Q for the tunable inductor.

Abstract: In order to carry the testing instrument to the required position in the horizontal/ inclined oil well, the downhole robot is designed. The downhole robot has a self driving force which is produced by the electrical motor in the robot, so it can carry the testing instrument reliably. In addition, the mechanical structure is simplified compared with that of the other downhole robot. Firstly, the mechanical structure design of the robot is introduced. The robot includes three parts: driving module, centralizing module, and base. Then, the driving force required and the power for the electrical motor in the driving module are calculated when the robot runs in the oil well. The simulation result shows that the downhole robot can work reliably in the oil well.