Applied Mechanics and Materials Vols. 401-403

Abstract: The virtual prototype model of air-conditioner piping system is set up based on ANSYS software, modal analysis and harmonic analysis is carried out on the model before and after modification. Some optimization is carried out based on the simulation and analysis results, comparing the two models before and after modification, simulation and the experimental results agree very well. It shows that the cost could be reduced and mechanical property is also good after optimization.

Abstract: This paper presents a novel common approach to analysis the transmission angle of a type of parallel manipulators whose traveling plate has only translation in the workspace and each limb is made up of three joints and two moving links. Two types of transmission angles are defined to evaluate the kinematic performance of parallel manipulators, with which the direct and indirect singularities can be identified in a straightforward manner. Considering the effects of transmission angles, a global and comprehensive index is presented. The kinematic optimization of a new manipulator has been taken as an example to illustrate the effectiveness of this approach.

Abstract: The principle of gas path electrostatic circular sensor was discussed in this paper, in addition, a monitoring experiment with self-made circular sensor was carried out on turbojet engine, and electrostatic signals were collected successfully to verify the validity and feasibility of the sensor. According to the signals monitored over 131h, typical signals of 233-240 phases were analyzed. It was proved that the unusual particles were caused by carbon deposition from fuel spray nozzle. Therefore, under real-time monitoring of gas path changes with electrostatic circular sensor, early warning could be provided for initial fault condition as well as real-time reference for condition-based maintenance.

Abstract: Automobile gearbox transmission efficiency is an important parameter which can directly reflect the gearbox design and manufacturing level . This paper analysis detailed the effect factors on measurement, test method, and data processing for transmission efficiency of automobile gearbox, summed up the actual test experience whereby the mechanical transmission efficiency measurement , plays a reference and guidance role on improving test precision.

Abstract: The electromagnetic force is an important characteristic parameter for magnetic suspension device, and magnetic circuit method is often used to calculate the electromagnetic force in engineering. However, it is not accurate to use magnetic circuit method to calculate electromagnetic force for magnetic suspension devices with large air-gap. In this paper three kinds of methods are used to study on the characteristic of electromagnetic force of magnetic suspension device with large air-gap: experimental, ANSYS calculation and magnetic circuit calculation method. Investigate the property and the variation regular pattern of electromagnetic force. Analyze the error distribution of magnetic circuit calculation method and find out the causes of errors, and then deduce a modified magnetic circuit formula to calculate the electromagnetic force of magnetic suspension device with large air-gap.

Abstract: This paper develops a new type of flexible finger employing the pneumatic flexible joints base on the modular design concept. In this work, the mathematical model of the grasping force of the flexible finger is derived and analyzed on the relationship between the air pressure and the grasping force. Further the grasping force experiments of finger using dynamometer and acquire the normal pressure of the finger with different combinations ventilation of joints are conducted, Also, the experimental results are compared with the theoretical results, which confirm the validity of the presented model.

Abstract: Compared with other factors, overland flow losses have stronger influence on the efficiency of direct-current conduction electromagnetic pump for casting. Mercury-media simulation of direct-current conduction electromagnetic pump is used. The mechanism of overland flow losses by changing the structure of liquid inlet was studied and got effective method of inhibiting overland flow losses. It can provide theoretical support for improving the efficiency of direct-current conduction electromagnetic pump.

Abstract: In order to solve the problem of pitting corrosion discrimination of rolling element bearing on vibrating screen. We established the vibrating model of pitting corrosion of rolling element bearing inner and outer rings faults on vibrating screen based on rotating machinery rolling element bearings operating mechanism and Hertz contact theory. We simulate this model and analyze the results. The results show that, when the outer ring of the rolling element bearing of vibrating screen has multi-point pitting corrosion, there is an apparent modulation phenomenon at the response amplitude. When the inner ring of the rolling element bearing of vibrating screen has multi-point pitting corrosion, there is a slight modulation phenomenon at the response amplitude.

Abstract: This paper developed a new type of hexapod robot using self-developed flexible space bending joints which can not only move from side to side or back and forth but also rotate. Then the principle of the movement and the gait of the hexapod robot were investigated, the kinematics model on translational displacement and velocity was followed. Furthermore, the test bench and pneumatic control system were set up, and the displacement, velocity and acceleration of the center of were acquired by high-speed camera shooting means. Finally, the stability of the gravity center and the control method of the hexapod robot were studied. The research of this paper provides a theoretical and practical basis for the application of bionic hexapod robot.

Abstract: In this article, the grey correlation is regarded as the decision index of Multiple Quality Characteristics of the Robust designed by the grey system theory. Then using the Analysis of variance to get the factors of Significantly affecting the stability and the best parameter. At last advantage of the method is proved by examples. It proves that grey system theory in robust design is practical greatly.