Applied Mechanics and Materials Vols. 303-306

Abstract: After changing the bearing box on a desulfurization booster fan, its horizontal vibration value is over 185μm beyond the standard. Through the test, it is decided that fan diaphragm coupling misalignment is the main reason for vibration. The vibration eliminates after readjusting the center.

Abstract: As the background of hydrological and geological conditions in Lu Xin Mine of Xinwen Mining Group, the transient electromagnetic instrument was used to detect the distribution law of aquifer around the first district. The detection results show that the roof and floor of 13# coal seam and the top of Jurassic are relatively rich in water, but the hydraulic connection between the upper and lower is relatively weak. The roof and floor of 6# and 9# coal seam and the bottom of Neogene are rich in water and the hydraulic connection is strength, and this place is located in the edge of basin which is easy for groundwater to supply.

Abstract: A practical project is taken for the example to analyze the application of frequency method in the effective prestress test of external prestressed bridge. In the process of solving the dynamic differential equation of tension cable, the effects of boundary conditions on the natural frequencies of external prestressed tendons are analyzed. The analysis results show that the fundamental frequency of the prestressed tendons under fixed boundary condition is higher than that under hinged-support support boundary condition, and the relative variance decreases with the increase of tensioning force. With the same tensioning force, the relative variance decreases with the increase of cable length. In the practical test, only the upper and lower bound limits can be obtained according to the measured prestressed tendon frequencies, while the real effective prestress values are between them. For external prestressed tendons, a kind of short tension cable, the frequency method can produce certain error in calculating the effective prestress.

Abstract: This paper based on an equipment which measure the outgassing of vacuum material,adopt some method, constant volume, otiose flux and double channels and so on, testing the deflation of stainless steel(316、304)brass H62, aluminium2A12, and other representative material deflation.We adopt light eradiate to heat up, and the temperature control range is 23°C~300°C, we study the rule of outgassing rate at different temperature, and use QSM to analyze the component of gas.

Abstract: The purpose of this study is to provide a new Kappa coefficient based on fuzzy scoring. This new Kappa is called fuzzy Kappa. Fuzzy theory has been widely used in quantitative research and many researches indicate its positive utility. Moreover, viewpoints of measurement according to fuzzy theory conform to the thinking of human thoughts. Therefore, it is feasible to measure the scoring of decision-making or judgment. In addition, Kappa coefficient is one kind of rater reliability and it is to measure the consistency on judgment among raters. Traditional Kappa coefficient is based on the crisp measurement and it violates the psychological nature of human decision-making. Therefore, in this study, fuzzy Kappa, which is based on the fuzzy measurement, is provided. Besides, data simulation is designed to compare of these two Kappa coefficients. The results show that fuzzy Kappa performs better than traditional Kappa. Based on the findings of this study, some suggestions and recommendations are discussed for future research.

Abstract: Because of the large diameter’s big volume, heavy weight, high thermal capacity and bad measurement environment, the workpiece’s diameter can only be detected in the processing locale. Though the rolling-wheel method can realize the large diameter online measurement, it can not achieve the diameter high precision measurement influenced by rolling-wheel skidding, compression deformation and temperature distribution. Focusing on the above problem, a new multi function rolling-wheel large diameter measurement system is designed. The designed system mainly researches the main error resource’s distinguish and amendment methods, such as the round grating graduator error, rolling-wheel shape error, rolling-wheel compression deformation, skidding of rolling-wheel to measured axis workpiece and its non-uniform temperature etc. The system can obtain the measured axis’s diameter and roundness real time while getting the needed information of error amendment by integrating multi opto-electronic switch, round grating, reference grating, micro-displacement sensor, temperature sensor etc. The system can realize diameter measurement extended uncertainty 5Dμm(D:1m～10m) and roundness measurement extended uncertainty 1.5Dμm.

Abstract: There arc many occasions we need to test its temperature in real time. This design is mainly studied the establishment and application of multi-channel temperature measurement system. In this paper, the authors introduce a multi-channel temperature detecting system which has a core of single-chip controller. The system measures the temperature by the temperature sensor, displays the temperature and deals with it on real time.The temperature detection system hardware circuit is simple, low cost, convenient temperature measurement, high measuring precision, and has better use value. The system is suitable for common occasions of multi-channel temperature measure, has great potential for development and practical significance．

Abstract: Non-contact measurement based on conoscopic holography is a kind of interferometry with common path, so it is not influenced much by other factors such as vibration. But the measurement result is affected by the uniformity of the crystal, which is analyzed in this paper, and corresponding method of adjustment based on image is discussed. And B-splines function is used to calculate zero position in measurement image, which is fitted over the patch image in the neighborhood of gray extreme points of the stripes, which is important to reduce the repeatability error, optimize design, and improve the accuracy of system.

Abstract: A new three-point method for spindle roundness error measuring was introduced, three capacitive sensors were installed on the measured shaft circularly, and with a certain angle each other, while the spindle was rotating with a certain speed, the capacitive sensors had measurement on the circular profile simultaneously, then through linear combination for three-sensor output signals, the roundness error was effectively separated from the spindle error. There were no strict requirement to initial installation position by using capacitive sensors, as long as ensuring the change of measured rotor error within the linear range of sensors, we could realize effective measurement. The experiment results have verified the effectiveness of roundness error measuring system based on three capacitive sensors.

Abstract: Due to the uncertainty in the testing process of electric equipment, Bayesian network is introduced to modify the hybrid diagnostic model, and the HD-BN model is established which has the ability to deal with uncertain information. Considering the relations between functions and failure modes, the priori probabilities of failure modes are corrected, and the uncertain matrix expressing relations between failure modes and tests under uncertainty is acquired based on Bayesian inference, which lay the foundation for further optimization of design for testability.