Advanced Materials Research Vols. 532-533

Abstract: The first order optimization of the ANSYS design module is used for optimizing the stucture parameters of wall thickness and the ribs. And a comparison of static and dynamic modes is made between the original model and the optimized one under the same load condition. The results show that total volume of the optimized model is significantly reduced compared with the original one with little change in aspect of static and dynamic characteristics.

Abstract: the system structure of a multi-channel data acquirement system is introduced in this paper. The communication interaction circuit between the main control system and signal conditioning circuit is described. The SPI bus communication type is adopted between C8051F320 and FPGA. The speed and accuracy of datum transfer must be considered in the communication design, so the CRC calibration is used.

Abstract: Objective of knowledge management is to ensure that the right information is delivered to the right person just in time, in order to take the most appropriate decision. So classification is needed in knowledge management when technological knowledge is presented to designers in an automated knowledge management system. In this paper, we explore a method to classify knowledge through the module attributes in the manufacturing process. We can obtain the right knowledge quickly through the classification options so that the validity and velocity of the knowledge management are increased dramatically.

Abstract: Based on the analysis of existing product specification STL, IGES, STEP, a new product model approach based on feature was put forward. According to data specification method, this article studied the specification description technology. At last, with reference to STEP specification, a new neutral text data format of this method was designed, which contained the construct feature information.

Abstract: The nondestructive estimation of key parameters during plant-field chicken manure composting is of great importance for quality evaluation. In the process of developing regression models using near-infrared spectroscopy (NIRS), methods used for wavelength selection significantly influence on the efficiency of the calibration. This study explored the method of genetic algorithms (GAs) for selecting highly related wavelengths to improve NIRS models for moisture (Miost), pH and electronic conductivity (EC), total carbon (TC), total nitrogen (TN) and C/N ratio determination in chicken manure during composting. Based on the values of coefficient of determination in the validation set (R²) and root mean square error of prediction (RMSEP), the prediction results were evaluated as excellent for Miost, TC and TN, good for pH and EC, and approximate for C/N ratio. But GAs had better performance than using full spectrum for near-infrared spectroscopy model construction in the process of evaluating key parameters during plant-field chicken manure composting.

Abstract: Sheet metal parts are widely used in various fields of mechanical industry. Unfolding is the first process of sheet metal processing. Due to the traditional manual way of sheet metal parts with large labor intensity and low efficiency, so the mode of production of sheet metal parts must be improved for quality and efficiency. Along with the conditions of computer aided design and production needs of the sheet metal industry, sheet metal CAD system is proposed to establish. At present, sheet metal systems are mostly based on second development of three-dimensional software to set up. So this paper is based on UG for second development to establish the sheet metal system. This system concentrates the study of method of parameter design and automatic unfolding of sheet metal parts. Parametric design and unfolding model of sheet metal parts is accomplished through the establishment of unfolding model and write control program. The principles of parametric design and second development tools of UG are specifically discussed in this paper. Unfolding model is created through the establishment of the parameters and considering plate thickness.

Abstract: The buffeting performance of free-standing tower of JiangHai Navigation Channel Bridge, a cable-stayed bridge, under yaw wind is investigated by means of wind tunnel test of aeroelastic model. It is found that the variation of buffeting response of free-standing tower with wind yaw angle is not monotonous. The lateral buffeting response on the top of the free-standing tower reach their minimal values and maximal values at around 150°and 180°of wind yaw angle respectively and the longitudinal buffeting response attain their maximal values at around 90°of wind yaw angle. Also, at the 2/3 height of the tower the lateral buffeting response and torsional buffeting response get their minimal values at around 150°of wind yaw angle, and at around 180°achieve the maximal values. It is also seen that, the buffeting response changes with the wind speed at a conic curve approximately.

Abstract: Spring vibration isolators and rubber damping vibration isolators are often used in active isolation engineering of water source heat pump units. The method is inefficient in shock and low frequency vibration isolation. Because the stiffness of equipments reduces with the isolation system the vibration severity itself becomes too big for working safely. Particle damping materials can absorb vibration energy to reduce vibration. The paper testifies that successful application of particle damping materials in vibration reduction of water source heat pump units is a practical simple way with low cost.

Abstract: High-speed on-off valve has been introduced in this paper with its concept and applications in various industries. Its trend and development in the future is optimized. This technology does challenge the proportional and servo technology in hydraulic area, because the technology can be used in displacement control of hydraulic pump, proportional and servo system, valve bank shifting, digital cylinder and so on.

Abstract: Current ceramic is used as the material for high speed ball bearing for its low density and lubricant performance; however the most common material for the high speed ball screw is chromium-molybdenum steel rather than the ceramic. Following the hertz contact and raceway control theory of the ball screw and considering the centrifugal force and gyroscopic moment acting on the ball screw, the dynamic model of high-speed ball screw was set up. The effects of different types of working ceramic ball chains on the mechanical properties of the ball screw were studied and compared through multi-body dynamic simulation. The result has shown that these factors affect the dynamic characteristic of ball screw dramatically, and the dynamic characteristic of ball screw at high speed is greatly different from that of ball screw made by chromium-molybdenum steel.