Papers by Author: Yu Xian Zhang

Abstract: Design an experimental method which can test the strength change of materials under the ultrahigh pressure, and a set of experimental data about the LY12 duralumin alloys materials yield strength and tensile strength are gained under the different ultrahigh pressure environment. The analysis result shows the strength of LY12 duralumin alloys will enhance. Because of effect of ultrahigh pressure, both yield strength and tensile strength increment of materials will approximately increase linearly. Beyond this, the method that can effectively build ultrahigh pressure environment has guidance significance for a real project.

Abstract: In this paper, author analyses the basic principle of fault diagnosis in motor device, and discusses systematically the modern methods of fault diagnosis in motor devices, and overviews the characters of each method and points out the trend of fault diagnosis in motor device.

Abstract: Tubular components are widely used in the areas of automotive and aerospace industries due to their excellent properties. A mathematical model considering the bulged region as a parabola curve is proposed to examine the plastic deformation behavior of a thin-walled tube during the free hydro-bulged process. The finite element simulations of the free hydro-bulging process are carried out to verify the approach indirectly. The results indicate that the model is accurate and acceptable to figure out the circumferential radius, wall thickness and axial radius of the bulged profile.

Abstract: First of all, the working principle of infrared thermometer and the structural principle sketch map for measuring the temperature of rotary wheel disc through infrared thermometric technology are briefly introduced from the physics aspect. Secondly, the type of infrared thermometer is selected according to the practical request of low or high temperature measure of rotary wheel disc. Finally, the same point temperature of the turbine wheel disc of an engine is measured through infrared thermometer and thermoelectric couple in the heating status, and the measure results are compared, which dictates that the infrared thermometric system could achieve an upper detection precision and satisfy the practical engineering request.

Abstract: According to the equation of shrunk interface pressure and the condition of diametrical ratio based on the theory of equal strength, it is found that the diametrical ratio isn’t true of the condition of diametrical ratio and the distribution of stress isn’t very equality through analyzing and calculating the diametrical ratio and stress to a super high pressure cylinder. Then aim at the problems existed in the super high pressure cylinder, it is taken the improved design. The super high pressure cylinder has much better than original one in distributing of stress. It is shown that the improved design project has a better technical result.

Abstract: Through the analysis of stress in ultra high-pressure cylinders, found that its stress distribution is very uneven. In order to use the principle of autofrettage for improving design of the cylinders, first with Faupel-Furbe formula to calculate estimates of diameter ratio, and thus are inner and outer diameter of the cylinder block. Then the cylinder is determined parameter of autofrettage on the cylinder such as the optimum radius of elastic-plastic junction and the optimum autofrettage pressure. Finally, analysis and calculation of stress in improved design cylinder, the results show that the improved design of cylinder have a greater degree of improvement in weight, size and stress distribution of three areas. Key words: autofrettage; ultra-high pressure cylinders; diameter ratio; stress distribution.

Abstract: Product design is a complicated thinking activity of creation of human. Based on analyzing product design and its process, using a theory and method of aggregating and mapping, models of product design, process of product design, process of conceptual design of product were constructed, a frame of network arithmetic of a process of conceptual design of product was presented, its flow of decomposition and integration was particularly defined, a good base for modeling and ruling of process of product design was founded. At the same time, a useful exploration of development of a computer support implement for process of product design at all life cycle was made.

Abstract: The characteristics of stress distribution in high-pressure vessel are analyzed at first. Then the formula of inner pressure is derived. Through analysis the formula, a conclusion that the maximal inner pressure the high-pressure vessel can support goes steady under the diameter ratio is more than 5. Then the formula of equivalent stress at the dangerous position (inside wall) in high-pressure vessel is educed according to the fourth strength theorem and the quantitative relationship in the vessel’s inside pressure and diametrical ratio and the fatigue limit further is founded. Finally, the advice that proper structure is adopted to improve the cylinder’s inner pressure when design thick wall high-pressure cylinder according to relationships as above. These advices have a definite directive significance for how to design and use vessel effectively.

Abstract: Mechanical analysis is carried out to the deformation of workpiece when turning slender shafts in the normal and reversed direction under two different conditions of clamping. Mathematical models are set up for the calculation of bending deformation resulting from cutting force in condition of normal and reversed turning. An example is given to show that bending deformation and the resulting machining error in conditions of reversed turning is much less than that in normal turning. The result has been verified by experiments. The mechanical model and numerical analysis can be used in the processing design of slender shaft turning.

Abstract: Waterjet abrasive nozzle is the key component for accelerating abrasive particle velocity and its diameter has important influence on water jet. The relationship between nozzle diameter and waterjet cutting performance has been studied by experiment. The results show: The incision depth and width of specimen decrease linearly with the decreasing of nozzle diameter; The linearity of jet moving direction and the size of kerf angle of specimen are independent of nozzle diameter. Under the same pressure, reducing the nozzle diameter make the penetration capability to reduce, thus, the cutting quality decrease.