Applied Mechanics and Materials Vols. 217-219

Abstract: Thermal deformation of spindle box is an important factor affecting processing accuracy of the high precision CNC machining center. In order to research the distribution of spindle box’s thermal deformation, physics-environment method of sequential coupling analysis was used to analyze thermal-structure coupling with the finite element analysis software ANSYS. The results show that the rise of temperature of motor is the highest, and the rise of temperature of the back-end of spindle is the lowest. Thermal displacement on the front of spindle is the largest, and it is the main part that affects the precision of machining center.

Abstract: Micro-variable Radiator with its small volume, light weight and less power consumption quite meets the requirement of Micro/Nano satellite thermal control. Prototypes fabricated by bulk silicon technology have poor thermal performance owing to their confines of material and process. In this paper, a novel micro-radiator based on laser micro processing technology and polymer material was proposed, its operational principle was introduced and the relationship between structural and thermal performance was analyzed theoretically. A prototype was fabricated by UV laser micro-processing, dip-coating and magnetron sputtering technologies. Test results show that the actuation voltage is 97V and variation of radiation power is about 0.1W.

Abstract: Constant volume transparent test combustion chambers are extensively used for investigating injection and fuel burning properties of various combustion engines. Their configuration depends on the engine type and the research purpose. Material of components, shape and dimensions of the chamber and its parts, ease of use, accessibility, sealing and safety of the assembly are the parameters needed to be considered in designing the test cell. This paper explains, structural design of a test combustion chamber and its optical windows using finite element analysis of ANSYS 12.0 software for bearing high pressure variations and thermal shocks of combustion. It was designed for conducting CNG direct injection study on direct injection SI CNG engines for maximum design pressure of 100 bars. Optical diagnostic methods and high speed photography through quartz windows are used for the jet and flame developments. Satisfactory test results of the fabricated system proved that the finite element method can successfully be employed for design of such a system.

Abstract: This document presents fault diagnosis method of rolling bearing based on blind source separation. The algorithm based on fast ICA is improved to separate fault signals according to the rolling bearing’s fault characteristics. Through the experiment it is shown that the algorithm can separate the signals collected from rolling bearing and gearbox effectively, which can provide a new method for fault diagnosis and signal processing of machinery equipment.

Abstract: Aiming at integrating Tritech Company’s Typhoon color zoom camera and Kongsberg Company’s underwater pan and tilt unit OE10-102 to build the underwater monitoring system, this paper designs a method, which uses STM32F103C8 as the core chip to design a protocol converter. The protocol converter could receives and analyses the PELCO-D data frames from RS-485 bus, and then produces corresponding commands to control the cameras and rotator units. Besides, this paper provides a new online program update method based on RS-485 channel, which could make full use of the existing 485 channel to complete user application program updating for the protocol converter without disassembling the deceives. Practice has proved that the methods mentioned are practical and stable.

Abstract: In ECM process, insulating by-products exists in the inter-electrode area. These by-products disturb the current flow between the tool and workpiece electrodes, and thus affect the machining accuracy. As one of the ways to remove the by-products, a method was proposed to apply ultrasonic vibration to the tool electrode. However, the influence of the electrolyte concentration and the effect of ultrasonic vibration on the machining characteristics of the WC alloy have not been investigated yet. Therefore in this study, these influences were experimentally investigated. It was found that the machining accuracy is increased by using the low concentration electrolyte. Also, machining of the tungsten carbide (WC) alloy when applying the ultrasonic vibration to the tool electrode becomes possible.

Abstract: In recent years aircraft maintenance practices have been influenced by changes in aircraft design philosophy and improvements in engineering technology. Advances in manufacturing techniques and material specifications have made it less necessary to carry out frequent disassembly of aircraft and components to establish confidence. The need to be competitive and to reduce costs has meant that the aviation industry has sought to gain advantage from these improvements by moving from time consuming and cost extensive, invasive maintenance to a philosophy of on condition maintenance (OCM). The research is aimed at highlighting an OCM based maintenance methodology by carrying out an extensive study on structural integrity of various vintage Chinese fighter aircraft. The study finds that the structure of Chinese fighter aircraft is robust and is capable of flying for more hours/years than specified by OEM. The study will help air forces operating the ageing Chinese fighter aircraft in extending the lives of their respective fleets well beyond the OEM prescribed limits.

Abstract: The band gap of 2D perfect and defect phononic crystal are calculated by using plane-wave expansion (PWE) and supercell plane wave method, which is consist of Al2O3 embedded in the epoxy resin with a square arrangement. Compared to the perfect, the gap of defect will become wider. As the size of defect length ld varied, the band structure changed. It is found that the acoustic wave only propagates along the path of defect when the propagation of acoustic wave is simulated on the 900 bending defect phononic crystals by matlab. It means that the waves are localized. So the defect mode of phononic crystal can be used as acoustic waveguide along the specific path.

Abstract: The pretreatment of the tube wall's surface needs to be done before coating and plating. The cleaning and derusting play an important role in the pretreatment. This paper designs the cleaning and derusting system of the steel tube inwall by premixed abrasive jet technique. The system consists of the generating device of premixed abrasive jet, the abrasive retrieval device and working mechanism. The test of clean and derust were carried on steel tube inwall by the system. In the test, the large inner diameter of pipe fittings adopted the oblique type nozzle, the small ones adopted the conic abrasive jet nozzle. The test shows that the designed system can achieve the purpose of cleaning and derusting on steel tube inwall. The appropriate working parameters: the working pressure is 12MPa, the rate of water flow is 30L/min, the abrasive weight consistency is 30%.

Abstract: Studying how to distribute the sampling points on processing surface has important practical significance on improving the detection quality and efficiency. So, this paper introduced Bayesian networks to the research of sampling points reasonable distribution, carried out Bayesian networks classifier learning of four typical sampling methods and the result obtained through analysis experimental and simulation data verify the feasibility of this method.