Applied Mechanics and Materials Vol. 197

Abstract: Wind power industry enormously expanded during the last several years. However, wind turbines are subjected to different sorts of failures, which lead to the increasement of the cost. The wind turbine gearbox is the most critical component in terms of high failure rates and long time to repair. This paper described common failures and root causes of wind turbine gearboxes. Then it focused on fault diagnosis and monitoring techniques for the wind turbine gearbox. The challenges and future research directions were presented, and the simulator rig of wind turbine gearbox was designed to develop condition monitoring and fault diagnosis techniques for wind turbine gearbox.

Abstract: According to the experimental analysis on characteristics and combustion law of the biomass briquette, it designs the biomass briquette boiler based on the detailed thermodynamic calculation to promote the boiler’s combustion and thermal efficiency. The boiler adopts the chain grate stoker which strengthens the combustion intensity of the hearth. The longer the hearth becomes, the more intense the combustion of the biomass briquette is, so that the biomass briquette boiler of thermo performance design has helped realize such goals.

Abstract: To solve the cooling problem in modern electronic device, a kind of heat pipe radiator was designed and manufactured in this paper. The heat transfer performance of heat pipe radiator and its relationship with air velocity were investigated by experimental method. The experimental results show that the heat pipe radiator can meet the temperature requirement of electronic device with the power range from 40W to 160W. To keep the operational temperature of electronic device with power of 160W under 75°C，the air velocity should be keep at 1.7m/s. The heat dissipation performance of heat pipe radiator was enhanced with the air velocity increased from 0.2m/s to 1.7m/s.for the electronic equipment with power of 160W.

Abstract: On the basis of fluid dynamics, this paper deduced the pull force formula of main nozzle on air-jet loom and introduces a method of experiment to test the airflow velocity in the exit of nozzle. The effect of different parameter structure of main nozzle on the pull force had been studied. It was observed that the inlet of thread tube was a bottleneck of main nozzle and the main development of main nozzle lengthens the thread tube. The theoretical findings were found to be in good agreement with experiment finding and this verified that the formula for pull force was reasonable.

Abstract: We have devised a way of segmentation and progressive transmission of diseased MRI images. We use Particle Swarm Optimization (PSO) to get the region of interest (ROI) of the diseased MRI image. We use the concept of Multi-resolution Wavelet analysis to de-noise the ROI. We use Stationary Wavelet Transform together with Soft Thresholding Technique for de-noising purpose. A variable mask is used to get the segmented image. Varying percentages of DCT coefficients are used for progressive transmission of the diseased MRI image. Clustering of the images using K-Means algorithm result in predominantly two cluster namely that of diseased cells and background. Test on various MRI images show that the small diseased objects are successfully extracted irrespective of the complexity of the background and difference in intensity levels and class sizes. The proposed method only transmits the diseased MRI for further diagnosis of the disease and treatment.

Abstract: As the optical power variation is relatively small before and after the Pt/WO3film was exposed to hydrogen gas, traditional detective method to measure directly the variation of optical power in the fiber core is susceptible to interference. Therefore a new detection method, which is able to improve the relative variation for nearly 9 times by detecting the variation of optical power in the evanescent field, was proposed through mathematical analysis and simulations. The fundamental structure and working principle of step-index single mode optical fiber sensor were introduced.

Abstract: This article expounds that there is consistent methodology between Industrial Engineering (IE) and Value Engineering (VE) from the aspects of the value orientation, the targets and the system view, and explores the differences and similarity of technical means. Based on the innovative thinking of Hehe philosophy and following the trend of combined use of IE and VE, this paper builds the integrative system of “IE+VE” and proposes the “tool kit” under the consistent pursuit of value.

Abstract: The flow-induced vibration noise generated by the elastic plate with cavity (EPC), which is a common structure on the surface of autonomous underwater vehicle (AUV), can not be ignored with the impact on the signal accuracy of the acoustic instruments mounted on the AUV. In this paper, the fluid-solid coupling vibration noise of elastic plate with a cavity has been modeling by the large eddy simulation (LES)-Lighthill equivalent source method. Then the fluctuation pressure spectrum of the flow field and the radiated noise field are analysed. According to the characteristic of the radiated noise field, the sensitivity of the sound power with respect to thickness of the EPC is calculated. Based on the results of sensitivity analysis, the flow-induced vibration noise generated by the EPC is reduced by local optimizing thickness of the EPC, with the premise of not increasing the structural weight.

Abstract: According to the different values of companies and different stages of life cycle, this paper analyzed the relationship between the different priority orientation and the combination of competitive advantage, and estimated the effects of different combination on the competitiveness of green products. Used the impact curve and cost curve, we analyzed the most influential factors to the overall competitiveness of green products in the main factors of competitiveness, and ordered them in accordance with the impact of them to established the lasting competitiveness of products. This provided a basis for the focus of future work of companies.

Abstract: The reliability of a reinforced concrete beam has been largely discounted when it under the action of fire. For a more accurate description of concrete beams’ reliability, the impact of cracks in reinforced concrete beams has been taking into account. Concrete is divided into elastic zone and plastic zone to calculate its strength. A simple and feasible time-variant model of reliability index of reinforced concrete beams under fire has been given. The effect of ISO834 temperature rising curve on the reliability index of concrete beam at different time has been analyzed. The reliability of a reinforced concrete beam under the ISO834 standard heating curve was assessed by first order second moment method.