Applied Mechanics and Materials Vols. 121-126

Abstract: In order to solve the problems of transducer design, Modeling and simulation analysis carried out, establishment of spring stiffness, damping piston, the piston stroke, and the relationship between the system periods. In the simulation results on the transducer have been studied, analyzed and evaluated. The results showed that: The system designed matches with the actual requirement.

Abstract: As one of the key components of nuclear power equipment, large nuclear power head has a complicate shape, great allowance of processing and difficult to produce. There is no any successful experience for reference. In this paper, one type of nuclear power head is our research object. We mainly researched on the NC processing programming of large nuclear power head and implemented processing simulation by alternative applying variety of processing methods, including calculation and simulation of tool path, generation of pre-processing files, and development of post-processor based on specific milling processing center, and the generation of NC codes. Finally, through Vericut, the simulation software platform, simulation verification of NC codes was implemented. The results indicated that the processing scheme was reasonable, NC codes were right and there was no phenomenon of over-cutting and under-cutting happening.

Abstract: GA approach suitable for solving object Recognition problem is described and evaluated using a series of simple model problems. Usually GA calculation produces enormous amount of data that contains rich information, of which only a tiny section is commonly utilized runs through the design optimization. An application of Genetic Algorithm optimization with Noise characteristics would give many insights into how to allocate various image reconstruction options in different echelons, GA employing a global search might identify a better solution in an different area of the search space.

Abstract: On the basis of the relation between force and deformation when the plastic deformation of soil mass is studied, nonlinear vibration roller model is built. Based on one type vibratory rollers select the system parameters and calculate the natural frequency. And according to the selected numerical value proceed the numerical simulation with different excitation force frequencies. Meanwhile, obtain and analyze the experimental data according to the vibratory roller experiment. Then the system response characteristic of nonlinear vibration roller is obtained, and the availability of system model is checked. All above provide the valuable theoretical basis for the research of vibrating compacting.

Abstract: A new type of discrete clamp stretch forming machine based on flexible holding technology was developed to improve the performance of traditional rigid clamp stretch forming machine used for double-curvature metal sheet forming, and its forming characters were illuminated simply. The FE model of flexible discrete clamp stretch forming was set up, and extensive numerical simulations of spherical parts for both the flexible holding mode and the rigid holding mode were carried out by dynamic explicit finite element analysis. The numerical results show that the distribution of stress, strain and thickness were well-proportioned in the flexible holding mode. The larger the spherical radius is, the smaller the minimum transitional length of sheet metal is. The transitional length of 60mm is suitable for flexible discrete clamp stretch forming in the case of considering the forming quality and material utilization. Then, the stretch forming experiment proves that the flexible holding technology is feasible, and the error contrast illustrates the new type of discrete clamp stretch forming machine is practicable.

Abstract: Exhaust ejectors are good ventilations and cooling equipments. By the method of numerical simulation, researches on cylindrical exhaust ejector, lobed exhaust ejector and lobed exhaust ejector with twisted blades are conducted in this paper to study the effects of different ejector structures on flow field uniformity. The results show that: lobe structure can well improve the velocity field uniformity and temperature uniformity field of the ejector; meanwhile it can also ensure that there is no obvious change of the ejector coefficient, but the total pressure loss is larger; while the flow field of lobed exhaust ejector with twisted blades possesses more uniformity.

Abstract: In order to study the interference and destructive effects of electromagnetic pulse for electronic systems, a test was done for an SCM system to check the irradiation effect of ESD EMP for it. According to the result of the test, under the effect of ESD EMP, the SCM would suffer multiple kinds of faults. This paper mainly introduces an exterior RAM effect test done for an SCM and the corresponding measures taken on the basis.

Abstract: This paper proposes a new image segmentation algorithm to detect the flame image from video in enclosed compartment. In order to avoid the contamination of soot and water vapor, this method first employs the cubic root of four color channels to transform a RGB image to a pseudo-gray one. Then the latter is divided into many small stripes (child images) and OTSU is employed to perform child image segmentation. Lastly, these processed child images are reconstructed into a whole image. A computer program using OpenCV library is developed and the new method is compared with other commonly used methods such as edge detection and normal Otsu’s method. It is found that the new method has better performance in flame image recognition accuracy and can be used to obtain flame shape from experiment video with much noise.

Abstract: The multi flexible body dynamical simulation model of dynamical vibration absorption lathe tool with large length to diameter ratio is built up according to the actual experiment lathe tool by using the software ADAMS and ANSYS. The experiment data which are consistent with the simulation result verify the correctness of the multi flexible body dynamical model. Aiming at reducing the peak value of system frequency response, the dynamical vibration absorption system is optimized. The optimized frequency curve shows that the system frequency response is improved obviously. On this basis the influence of the mass of heavy turning body on the vibration system is discussed. Also, the relationship of the mass of heavy turning body and the optimal system parameters including equivalent stiffness coefficient and equivalent viscous damping coefficient is studied. This offers the design considerations about the structure of the dynamical vibration absorption lathe tool with large length to diameter ratio.

Abstract: Modal analysis was carried out to calculate the natural frequencies and vibration modes of 20 orders for a certain pipeline system of the outdoor machine of air-conditioner using finite element simulation. Excitation was exerted on the pipeline system for harmonic analysis, and the optimized design was proposed based on the analysis of simulation results. Results prove that the design by changing the direction of pipeline is more effective than that one by adding damping blocks to improve the natural frequency of pipeline system, and the optimized design can avoid the resonance zone of the working frequency of compressor. Besides, the maximum vibration displacement is also greatly decreased.