Advanced Materials Research Vols. 230-232

Abstract: The paper mainly discussed about the development of the electrochemical machining, from early direct-current ECM (DECM) to pulse current ECM (PECM), high frequency pulse current ECM (HPECM) and ultra-high frequency pulse current ECM (UHPECM). Microscopic mechanism of the machining results were discussed in the paper. We studied the influence of power frequency to the result, effects of pulse effect on the finishing result were also researched. Besides, high-frequency group pulse and ultra-high-frequency group pulse ECM were researched in the paper, comparing the two machining methods, some important conclusions are showed as follows.

Abstract: Using the separation line technology, established a FE model of two-dimensional cutting process for AISI4340 steel and discussed some basic theory and pivotal questions associated with the simulation of cutting process including the Johnson-Cook material model, the contact model between tool and chip, criteria of chip separation and so on. In order to study the impact of tool rake angle on the chip morphology and the cutting forces, the high-speed cutting process for AISI 4340 steel was simulated based on ABAQUS software. Also, analyzed the influence of mesh azimuth on the chip morphology and its temperature distribution.

Abstract: Due to the variety and the randomicity of its influencing factors, the monthly load forecasting is a difficult problem for a long time. In order to improve the forecast accuracy, the paper proposes a new load forecast model based on improved GM (1, 1).First, the GM (1, 1) is used to forecast the load data, which takes the longitude historical data as original series, the increment trend of load was forecasted and takes the crosswise historical data as original series, the fluctuation trend of load was forecasted. On this basis the optimum method is led in. An optimal integrated forecasting model is built up. The case calculation results show that the proposed method can remarkably improve the accuracy of monthly load forecasting, and decrease the error. The integrated model this paper describes for short-term load forecasting is available and accurate.

Abstract: The rice husk powder was modified by polymer (lactic acid) (PLA) and Maleic anhydride (coupling agent, MAPP). Composite material was prepared in the way of melt blending. The mechanical properties, water absorbability of rice husk/polymer (lactic acid) (PLA) composites, and the relations between these properties and microscopic characteristics were investigated. The result showed that, with the increasing content of rice husk power, the maximum bearable tension and tensile strength increased; Water absorbability after 2 hours’ immersion hadn't significant change, but after 24 hours’ immersion, the water absorbing capacity had obvious addition. The study also showed that coupling agent could significantly reduce the water absorbability of composite materials; The use of scanning electron microscope (SEM) found that the interface became smoother, the adhesion between PLA and rice husk powder became closer when add the coupling agent to the rice husk powder, it also could well explain the differences between water absorbability and mechanical properties.

Abstract: The study of cold state testing and evaluation analysis were carried on the practical running chain-grate stoker, which has an air-supply system with air storehouse and airtrough, to study the air-distribution, air leakage, air tightness and air governing. The result shows that horizontal air distribution across the furnace and the air tightness of the components such as the air port (damper) and airtrough are good. However the air leakage is large because of the complex structure and the high demand of integrated air tightness either in the front or the back of the stoker. The cost of the stoker is high because of large quantity of machine work after casting and high demand of installation, thus the structure should be improved.

Abstract: In order to improve the performance of four wheel driver vehicle, structural characteristics of inter-axle torque distribution with planetary gear are analyzed, and a dynamic model of four wheel drive vehicle is established. A synthetic control strategy was proposed to achieve the engine throttle control, inter-axle torque distribution control and drive wheel brake control. Traction control system based on fuzzy logic control is designed. The simulation of traction control on split-µ road and low-µ road are carried out. The results show that, the traction control system for four wheel drive vehicle based on fuzzy control can prevent excessive slip of driving wheels, and vehicle traction property and dynamic performance are improved obviously.

Abstract: This paper presents a new model of multi-discipline knowledge reasoning for collaborative design. The main contributions of this study can be focused on three points: The first is to clarify the concepts and contents of the polychromatic sets and polychromatic graph. The second is to put forward the knowledge reasoning model for multi-discipline knowledge based on polychromatic sets. Finally, the mathematical solutions for contour matrix, the causal relationship between the adjacent and the same knowledge patterns are given.

Abstract: Major works concentrated on the energy conversion from mechanical friction work to heat; emphasized on the immediate contact surface of work material and rotating welding tool but with no in-depth analytical study to relate the loads that are transferred to the work material and the welding fixture especially at early stage of heat generation. In this work, a mathematical model is developed to predict three-dimensional force components and axial torque of the rotating tool based on contact mechanic principle in relation to Al6061 temperature-dependent material properties. The model shows the ability to be possibly adapted for different metallic material and physical properties. It suggests the exerted torque and loads calculation endured by work material involving friction and shear mechanism of two static-dynamic contacting surface; rotating rotational tool and the fixed work material, to be used as one of the option for optimization of the welding process such as to determine the ratio of slip, non-slip contact condition through comparisons of experimental and computer simulation on the Friction Stir Welding process.

Abstract: The optimal design of the toroidal worm plays a key role on its performance. The paper analyses the optimal design of the toroidal worm in detail, then points out the design rule of the toroidal worm and the key point of the optimal design. At the same time the program is also built on the optimal design. Based on the program, the optimization of the modification parameters of toroidal worm-gearing is solved.

Abstract: In this paper, the carbon fiber mechanical properties of wood composite board were discussed. The microscopic structure of the composite material was analyzed based on finite element method. A unit cell model was established, and element stiffness matrix of the model was developed. The model was used to predict the mechanical properties with feasible and accurate affects. The results of experiment showed that after carbon fiber being mixed, the MOE, the MOR and the IB of medium density fiberboard was significantly improved.