Papers by Author: Ke Zhang

Abstract: To grind fused silica in ductile mode, it was proposed to repair surface and subsurface micro cracks of fused silica by CO₂ laser irradiation. However, excessive residual stress remains on the surface because the melt fused silica on the surface quenches in air. It causes the critical depth of cut for ductile grinding fused silica to be smaller than 0.2μm. To investigate the distribution of the residual stress and look for an optimal manner of irradiation to control residual tensile stress, a numerical model of was built for simulating the dynamic behavior of fused silica when irradiated by CO₂ laser. Laser energy absorption, heat transmission, viscoelastic behavior of fused silica and thermally induced stress were considered in the numerical simulation. The results show how the residual stress is formed and distributed. We found that an appropriate control of the temperature field as a function of time and position in the laser process is the key to reduce the residual stress. Therefore, three kinds of processes were proposed to reduce residual tensile stress on the surface of fused silica introduced by laser irradiation. The residual stress distributions of these three processes were compared by numerical analysis to decide a better method of laser irradiation.

Abstract: The zirconia parts are limited by machined surface quality. The grinding force is one of the most important parameters of grinding and has effects on surface quality. The MK2710 grinder and resin bond diamond wheels were used in zirconia grinding. The grinding force was obtained by Kistler dynamometer. The paper focused on wheel speed and grain size on grinding force, and examined the surface by SEM. The research results indicated that decreasing the grain size, the grinding force increased and the surface quality improved, and increasing wheel speed could decrease grinding force to improve grinding surface quality. The results can improve zirconia ceramic parts surface quality and promote application.

Abstract: Using ProE software establish the digital prototype of wind power maintenance lifting platform and the clamping mechanism, import the clamping mechanism into ANSYS to analysis the static strength. Select the forced major important parts in clamping mechanism,hydraulic cylinder connecting pin board,use the Design Explorer modules in ANSYS Workbench introducing the response curves to do the optimum design, set the thickness of hydraulic cylinder connecting pin board and the work position of the hydraulic cylinder for the input parameters variable,with pin board by stress as output parameter variable, from nine groups of data, selecting the smallest stress group as the new design, analysis and calculate again. Results show that by stress of the optimized clamping mechanism is obviously improved, and the structure of whole clamping mechanism more reasonable and compact.

Abstract: To meet the urgent demand of maintenance and lifting equipment for wind turbine, combined with designation demand, two kinds of primary structure of the maintenance and lifting equipment has been proposed, analyzed and compared. By means of the Solid Works software the initial design on the two kind of the machine, the self-climbing crane and the trailed hoisting platform, have been conducted, the static analysis has been performed based on the mechanics model, and the advantages and disadvantages of these methods have been pointed out and compared in the paper. Compared with the self-climbing crane, the mechanical structure of the trailed hoisting platform is simpler, the control system presented more reliable, simple, easier realized etc, and the cost is lower. The self-climbing crane is high-automatic, but the design of crane high in the free degree and high in difficulty, and the climbing force focused on the wind turbine tower is too large. Conclusion The trailed hoisting platform is determined as the main design method to design the maintenance and lifting equipment for wind turbine.

Abstract: The article has analyzed the changes of temperature of different materials of the spindle, and considered 170SD30 Ceramic Motorized Spindle and the same model Metal Motorized Spindle as the research objects, analyzed the inside heat source and heat transfer mechanism of the high-speed motorized spindle; used finite element software to set up the model of the motorized spindle, and did simulation and analysis. Verified by simulation, heat transfer rate of ceramic materials is slower than the metallic materials, in actual operation of the process, due to different materials have different heat transfer rate, so the temperature distribution of the different materials of motorized spindle are different. This conclusion provides the basis to solve motorized spindle temperature field distribution.

Abstract: The unit of Electric spindle is decided processing speed and precision of the machine key functional components, it determines the development direction of machine tool industry. Use high-performance structure ceramic as electric spindle of spindle, bearing main of rotating parts material, mainly use ceramic material density is small, hardness higher good characteristics, improve the inherent frequency and life axis. Based on the modal analysis theory, the use of the laboratory's hammer excitation 170SD30 models of the ceramic motorized spindle by experimental modal analysis got its first three order inherent frequency and critical speed. Results show that all the ceramic motorized spindle rated frequency far below its first order natural frequency, rated speed far below its first order critical speed, it can effectively avoid resonance region that ensure the process accuracy.

Abstract: Abstract. This article completed the design of fan blade maintenance platform structure through the determination of fan blade maintenance platform design scheme and parameters, and then introduced the basic function, structure and working principle of maintenance platform, completed the fan blade maintenance platform from 3D viewing using solidworks. And did static analysis under 3 different working conditions on the platform through the ANSYS12.0, and calculated the intensity of structural stress and specific deformation under different working conditions. And get the results that the maximum stress and maximum deformation of the platform under 3 different conditions are 115.68MPa and 2.246mm, and it's destructive to counterweight balance guide rail and connection location of hoist installation frame and hoist. Results of analysis shows that the platform satisfies the mechanical property requirements and provides effective scheme for further optimizes choice of structural members.

Abstract: based on the structural characteristics of the truss structure, the mathematical model design model for a truss structure used in Mast-climbing Work Platform is built with Ansys design language, in which the maximum stress is the optimization objective and the bar orientation is the design variable, showing the constraints and loading condition in mathematical matrix expression, on this premise of the stiffness condition meets the requirement, the bar orientation brings about great influence on the truss structure optimizing, the triangular framework optimized to be quadrangle framework, the maximum stress has been decreased by 74.37%.

Abstract: Silicon nitride nanoscale cutting model was established by molecular dynamics simulation, and interactions force between atoms of work-piece was calculated by Tersoff potential function. Through the three-dimensional simulation of silicon nitride nanocutting process, the changes of cutting force, kinetic energy and potential energy in the nanoscale cutting process, and the effects of cutting thickness and cutting speed on the entire cutting process were analyzed. The results showed that the kinetic energy, potential energy and cuting force increased along with the cutting thickness increasing, both kinetic energy and potential energy decreased with cutting speed increasing.

Abstract: Based on the wind load calculation model increases Suspended Platform vibration characteristics of wind vibration coefficient, and gets Suspended Platform natural vibration period and inherent frequency by ANSYS finite element modal analysis, then determines the wind vibration coefficient, calculates the wind load of Suspended Platform in working state and non-working state. Aiming at three different conditions, analyzes the platform structure in the wind load the stress intensity and deformation. Through analysis to finds the most dangerous positions of Suspended Platform in three different conditions, provides effective references for the L Type Suspended Platform in wind-resistant design and optimization design.