Key Engineering Materials Vol. 621

Abstract: White body in the design process needs to meet the needs of a wide range of performance requirement. Adequate stiffness and modal are the basis to ensure the vehicle’s performance of vibration noise. Simultaneously, in order to reduce energy consumption and cost, the lightweight design of the white body has become the mainstream. In this paper, the optimization design is conducted for stiffness and modal of a commercial vehicle’s white body based on the theory of the finite element size sensitivity optimization design. Firstly, build the finite element model of a vehicle’s white body and analyze its stiffness and modal. Some changes were made to the car-body’s partial structure according to the distributing of strain energy achieved from above analysis, which improved the car-body’s dynamic and static performance initially. Secondly, choose panels needed to be optimized by reference to the density of strain energy and panels’ mass. Then, the car-body’s structure was optimized using panels’ thickness as design variables, stiffness and modal frequencies as constrains and minimizing weight of white car-body as objective. After the analysis of the result, modal separation was put forward to improve the quality of this finite element optimization design model. Finally, the car-body’s stiffness and mode nature entirely satisfied the requirements with car-body’s weight decreased.

Abstract: In order to improve the efficiency of life, reduce the labor intensity, On the basis of agronomic requirements, design a new type of tomato harvesting machine.Virtual design is aimed at cutting device,transporter,fruitseedling separating device,internalconveyer, transverse conveyer, Ascension conveyer, color select set, telescopic boom. By cutting machine, through a series of excluding foreign body, direct transportation loading, finished the harvest.The machine harvesting, transportation, separation and color to choose, and other functions in one body, make the post-harvest processing tomato can achieve enterprise standards.

Abstract: This document explains how to transform an ordinary float-type pneumatic measuring instrument by adding a right lights sensor on it. Then we design a suitable float for it through the theoretical calculation and the simulation with Fluent. At last, the research do a series of experiments and by the experiments, its nonlinear error is less than the ordinary float-type pneumatic measuring instrument. So the whole instrument is feasible. The final purpose of designing the float-type pneumatic measuring instrument based on the red lights sensor is to measure the overlap of the valve core & sleeve of the slide valve.

Abstract: Nowadays, wire sawing becomes the most advanced brittle crystals slicing technology because of its advantages of slicing larger crystals ingots into very small thickness, high surface quality, high yield wafers. In the process, the thin wire, which is the processing tools, travels at high speed, and subjects to external excitation from many aspects. Wire saw tension control is the core and difficulty of the control system. Mathematical models of tension subsystems were studied. The control strategy of swing arm motor tension direct closed-loop combination of speed difference indirect closed-loop was proposed. The developed tension control hardware and software system reached the functional requirements and technical indicators, and constant tension precision control was solved effectively.

Abstract: In order to obtain the heat dissipation regularity of heavy-duty vertical lathe faceplate with a large radius, mathematical model of convection heat transfer is established. According to the model, convection heat transfer process of the faceplate is analyzed at the velocity of 10~80rpm. The results show that velocity increasing not only impacts a greater influence on the temperature rising of hydrostatic bearing than the temperature rising of faceplate, but also drives the heat increased the heat dissipation, degenerated the heat concentration phenomenon. Experimental results shows consistent to the faceplate temperature numerical simulation results, the maximum error is 5%, which indicating that the numerical results conform physical regularities, the heat transfer mathematical model extends the range of applications of rotation convection heat transfer, so that vertical lathe heat dissipation situation analysis can be easier and more accurate.

Abstract: A comparative study on pressure field of hydrostatic thrust bearing with sector recess, rectangular recess, ellipse recess and I-shaped recess is carried out in order to solve the deformation of the hydrostatic thrust bearing. The Finite Volume Method has been used to compute three-dimensional pressure field of gap oil film between the rotation worktable and the base. This study theoretically analyzes the influence of recess shape on the bearing pressure characteristic according to Computational Fluid Dynamics (CFD) and lubricating theory. It has revealed its pressure field distribution law. The simulation results indicate that an improved characteristic will be affected by recess shape easily. Through this method, the safety of a hydrostatic thrust bearing with different recesses can be forecasted, and the optimal design of such products can be achieved, so it can provide reasonable data for design, lubrication, and experiment and deformation computation for hydrostatic thrust bearing.

Abstract: The thrust foil bearing, as one of the key parts in high-speed rotating machineries, is used to sustain the axial force, and its load performance has a crucial relationship with the structural parameters and working condition. In this paper the top foil is modeled as a thin plate supported by the bumps underneath. The finite element method (FEM) is used to calculate the structural deformation coupled with the pressure distribution obtained through the solution of Reynolds equation by the finite difference method (FDM). The effects of structural and operating parameters, such as rotational speed, eccentricity ratio, top foil thickness and bump foil thickness on the load capacity and frictional torque are discussed in detail. The results show that the increase of rotational speed, eccentricity ratio and bump foil thickness is beneficial to increase the load capacity and frictional torque. The effect of variation of top foil thickness on load capacity is not obvious, which implies that the top foil plays a role in building the lubricant surface rather than providing supporting stiffness.

Abstract: This article analyzes the deviation of existing stiffness measurement method and comes to the main components of the measurement error. Focus on the influence of the bending deformation all of aspects and contact deformation between the various links to the measurement accuracy. Establish the relationship between the actual deformation and the measured deformation to the spring tube through homogeneous coordinate transformation and finite element analysis, in order to identify the error sources impact on the measurement greatest, and improve the measure methods to against the main error source, eliminate the influence of the main error source to the stiffness measurement, then achieve the purpose of improving the measure accuracy.

Abstract: In this paper, we measure and statistic the 3d size of the Xinjiang wen-185 Walnut. And did its pressure test in three directions. Design double-rolling shell broken craft in four-point pressure with a self-hierarchical. Establish a mathematical model for walnuts shell-breaking with the technology. The walnut graded, diversion and shell broken were carried out in simultaneously to assurance an efficient shell broken rate and same time a high complete kernel rate.

Abstract: A hydrodynamic experiment apparatus is constructed to accomplish the measurement of hydrodynamic force on three-dimensional. This paper firstly introduces the mechanical structure of the novel hydrodynamic experiment apparatus. Then, it introduces the mathematical modeling of the hydrodynamic experiment apparatus which is based on the relationship between measurement data and the force on experiment subject. Finally, the error source of the mechanical structure and load cells were analyzed and the error compensation model is established to improve the measurement accuracy.