Applied Mechanics and Materials Vols. 52-54

Abstract: Utilizing emergency transshipment between two retailers at the end of the season of sales to meet special customer demand can be an effective mean for companies to reduce sale lost cost and/or holding on cost. This paper provides a decision rule for how much (if any) to transshipment, with the condition that the two retailers involved have profit objects and decision made respectively. While the model explicitly of fixed and variable transshipment costs for each of them, it is possible to decide the amount of proposition cost helping to bring about the emergency transshipment.

Abstract: The component distribution of adiabatic shear banding during high speed cutting(HSC) is important to understand the phase transformation during formation of adiabatic shear band and mechanism of serrated chip formation. This paper analyzed element distribution inside and near the adiabatic shear bands formed during HSC of 30CrNi3MoV high strength steel using electronic probe. It was found that there is no obvious element segregation, but carbon element tends to gather towards adiabatic shear band’s boundaries. The density of carbon inside the shear bands tends to increase with the increase of cutting speed. The results indicated that the diffusion and gather of carbon may occur during formation of adiabatic shear band. The diffusion mechanism may be short-range diffusion driven by high-speed deformation and high temperature rise.

Abstract: The first task of a lunar rover elevator after landing is to deploy road-set. Vibration amplitude is large and attenuation time is very long because of low material modal damping and litter outer damping on lunar, which can be a disaster for a space mission. The paper built the road-set deploying rigid-flexible coupling simulation model by ADAMS and Nastran software and measured the acceleration of the inner and outer road-set end by experiment. Simulation and experiment results show that gravity, material damping coefficient and torsion spring parameters influence to road-set vibration greatly and the methods to restrain road-set vibration are to optimize joint torsion spring parameters by kinetic energy least restrict and to enhance attenuation speed by optimizing the road-set appearance and increase its damping coefficient.

Abstract: A design method of structural optimization of large part of machine tools was proposed based on neural network and finite element method. With the pillar of XK713B numerically-controlled boring and milling machine as an example, the BP neural network model corresponding to structure parameters and dynamic characteristics of the pillar was built, and rapid sampling of the neural network model was carried out with the help of APDL language. Then, optimization of the design variables was done and satisfied results were obtained. Calculation results show that, by using the neural network model, error between calculation results and expectations is less than 5%.

Abstract: After modeling and calculating of whole machine, the static and dynamic characteristics are obtained, since it is difficult not only to judge out machine components’ influence on machining precision intuitively , but also to identify the weak link of the whole machine. Therefore, through extracting key nodes coordinates of machine components and deformation information of finite element software calculated, we brought forward a space vector transfer algorithm, calculated the contribution of components for tools and work piece system and expressed impact of machine components on tool and work piece system by histogram. By this means ,we can judge out the whole machine’s weak links intuitively. Take XK713B Vertical Milling Machine as the case research object, extract key nodes and their deformation information of general structure such as lathe bed , column, headstock, sliding table, workbench etc. By using space vector transfer algorithm, the result shows that the largest contribution to tool system and workbench system is column, which is the weakest link in the whole machine and its vibration type is swing. According to this, further optimize design of column can be proceed.

Abstract: Taking four in-wheel-motor electric vehicle as research subject, the paper focuses on the estimation of road adhesion coefficient based on curve. Through adding a forget factor, an improved algorithm on the basis of Forget Kalman Filter is proposed to estimate the slope of the curve at low slip rate. This new algorithm is proved effective through the real car test.

Abstract: This paper analyzed the dynamic performances of vertical machining center and investigated the problems of dynamiccharacteristics. The modal analysis in both experiment and simulation wascarried out to obtain the modal parameters. The vibrations of the machine spindle were tested to obtain the vibration spectrum under different spindle speeds. It synthesized and compared with the vibration and modal characteristic in order to investigatethe weak parts of the structure. It is concluded that modal characteristic has something to do with the vibration, and there is eccentric between the active rotor and driven rotor. This comprehensive comparison method for dynamic analysis is very effective.

Abstract: A novel wide band U-shaped monopole antenna with two C-shaped parasitic elements, suitable for WLAN and WiMAX operations, is pretented experimentally and numerically. The wide-band characteristics are obtained by using the U-shaped patch and the two C-shaped parasitic elements along the CPW signal strip. And the simulated wide antenna yields a 10dB impedance bandwidth range from 2.51GHz to 6.0GHz. The antenna is as small as 20×30×1.6mm3. The investigated antennas have been successfully designed, simulated, showing good impedance bandwidth and omni-directional radiation patterns.

Abstract: In this paper, based on the theoretical analysis and reasonable simplification, one-dimensional mathematical model is presented for the counter-current oxidation of ventilation air methane. The process of counter-current oxidation reaction is simulated by applying the computational fluid dynamics (CFD) software (Fluent), and the effect of the dominating working parameters (such as flow velocity and equivalence ratio and half cycle) are discussed on the temperature and rate of reaction within the counter-current oxidation reaction. The distribution of the temperature field and the reaction rate are simulated when half cycle is 30s, the equivalence ratio is 0.2 and the velocity 0.06 m/s, 0.1m/s and 0.2 m/s. The combustion characteristics are summarized for the device of counter-current oxidation reaction, and the effects of working parameters are analyzed on the burning characteristics. It is so important to increase the combustion efficiency and energy utilization.

Abstract: To solve the difficulties in machining toric spectacle lens, the turning method with slow tool servo was discussed. First, the experimental setup was developed, which have X-axis, Z-axis and C-axis, and the movement of the three axes can be simultaneously controlled by numerical control system. Then, the mathematical model of toric was established, and its machining model was analyzed and simulated. Finally, the machining experiments were carried in the experimental setup. The experiments showed that the turning method based on slow tool servo can meet the requirements for machining the toric spectacle lens.