Liu Jing-zhengLi Ling-lingLi Zhi-gangWang Ming-hui...
321-324页
查看更多>>摘要：As the core of intelligent computer aided design (ICAD), the expert system with the purpose of product design automation and intelligence has been developed rapidly. Knowledge expression, management, utilization, and access method has always been the core of artificial intelligence and expert system technology , Substantial literature both at home and abroad involved in the content and achieved certain results in the area of design. In the aspect of knowledge expression and management, including: the knowledge expression based on gene model[3], the knowledge expression based on design pattern[4], the knowledge expression based on Petri net, mixed knowledge expression, and so on. In the aspect of system reasoning, including: fuzzy reasoning[5,6], cease-based reasoning[7], integration reasoning, and so on. This paper mainly introduces some technologies and methods about electrical products at ICAD system with the above-mentioned two aspects. As a sub-system of ICAD system, the expert system for electrical apparatus designing was studied in the artificial intelligent technologies, including the way to build a large knowledge database managed by multi level frames and expressed by various knowledge expression methods, and the reasoning strategy suitable for the structure of knowledge database and integrated rule-based reasoning (RBR) with case-based reasoning (CBR) together. Based on these technologies, two-level expert system controlled by meta reasoning machine was built so that the reasoning efficiency was boosted very strongly.
查看更多>>摘要：In this paper, a Section Tool Module is built to implement the cross section design of vehicle pillar structures which is integrated in VCD (Vehicle Concept Design) system [1]. The module may lead engineers to create section database and to get proper design plan effectively. The sectional properties such as area, moments of inertia are generated. In addition, an optimal design technique applied in this module is presented to perform the optimization for single cross section, in which sectional property is defined as objective function. An example of the optimization for a single cross section which is extracted from a passenger car is shown to demonstrate the Section Tool Module.
查看更多>>摘要：This paper presents the design method of electromechanical products for saving energy based on energy flow analysis. The energy transfer model and energy correlation model are built through analyzing the relation of energy flow and products performance in order to address the conflict between energy saving and performance optimization. Based on the energy transfer model, the performance pertinences and performance margins of electromechanical products are analyzed with CAE technology and value engineering theory. Finally, the split air-conditioner's outdoor unit is studied and the design method for saving energy based on energy flow analysis is adopted to solve the conflict between air flow increasing and noise reduction.
查看更多>>摘要：To obtain the flexibility of choice of cutting tool and to compensate the wear of the cutting tool, this paper presents an interference-free toolpath generating method for multi-axis machining of a cylindrical cam. The notion of the proposed method is that the cutting tool is confined within the meshing element and the motion of the cutting tool follows the meshing element so that collision problem can be avoided. Based on the envelope theory, homogeneous coordinate transformation and differential geometry, the cutter location for multi-axis NC machining using cylindrical-end mill is derived and the cutting path sequences with the minimum lead in and lead out are planned. The cutting simulations with solid model are performed to verify the proposed toolpath generation method, ft is also verified through the trial cut with model material on a five-axis machine tool.
查看更多>>摘要：Unlike ductile metals cutting mechanism, the interfaces between fiber and matrix as a transitional layer experience mismatched deformation in machining process. In general, the most frequent operation performed on composite materials is drilling with a twist drill to generate a hole owing to their versatility and low production cost. However, delamination is one of the most common defects in drilling laminated fiber-reinforced composites and can cause a significant reduction in the load-carrying capacity of a structure. At the periphery, using such special drills as saw drill, candlestick drill and core drill, reducible to causing delamination damage than the twist drill. Experimental results indicated that the diameter ratio and feed rate have statistical and physical significance on the thrust force obtained with a core-candlestick drill.
查看更多>>摘要：This paper applied Grey-Taguchi method to optimize the micro-drilling of PMMA polymer with multiple performance characteristics. The four parameters being optimized are coating layer, feed rate, spindle speed, and depth of cut. The performance of the drilling process was evaluated by two performance characteristics, namely drill wear and surface roughness. The orthogonal array, grey relational analysis, and analysis of variance were used to study the two performance indices. The optimal combination of parameters was determined by using the grey relational grade, a performance index formed by combining the two performance characteristics. The experimental results show that TiAlN-coating drills generate least wear and thus possess the longest tool life and the best holes quality. Finally, confirmation experiments were conducted to confirm the validity of the results.
查看更多>>摘要：For applications of high-power LED illumination and advanced CPU electronic cooling, since the traditional plate heat sinks by aluminum extrusion are simple geometry only and with limited thermal performance, a new design and new fabrication process of heat sink for high-density heat flux applications is inevitable. In this study, a heat sink fabricated by vacuum die-casting is analyzed. To evaluate the thermal performance of this heat sink, two experiments, free convection measurements in an enclosure and forced convection measurements in a wind tunnel, are conducted by two experimental methods of thermocouples and IR thermograph. As to free convection experiments, compared to the free convection over a plate, temperature decrement by the attached casting of pin-fin heat sink is 46.2% for the input power of 10W. In the case of 15W heating power, temperature distribution along center pin shows uniformly distributed temperature along length direction, but there is a temperature difference of 9.5℃,varied from 86.9℃ to 77.4℃, at outer pin. As to the case of 10W heating power, there is a temperature difference of 6.5℃, varied from 69.2.9℃ to 62.6℃, at the outer pin. Furthermore, forced convection experiments show that resistances of heat-sink casting are decreased when Reynolds numbers are increased, and a linear relationship between pressure drop and Reynolds number is noticed. Base on the measurement results, this heat sink casting can be a feasible thermal solution of LED and high-power chip products.
查看更多>>摘要：Manufacturing of the future has to be more flexible and versatile in order to meet the ever changing needs of the customer. Most continuous casting machines today are rather inflexible in that they are designed to cast specific types of alloys and with limited size ranges, thus suitable for the mass production paradigm. This paper reports the design and development of a modular horizontal continuous casting machine (HCCM). The aim is to have a machine that can continuously cast a variety of ferrous alloys from carbon steels, low alloy steels, stainless steels to cast irons, and with ranges of cross-sectional areas. The modular design approach and quick-changing techniques are employed as the key design concept. The construction of the first prototype of the machine is completed and several field trials have been conducted. The results are promising. For carbon and low alloy steel billets, the overall structures and surface quality are good although the amount of porosities is rather large. The overall quality of stainless steel billets is better than that of carbon and low alloy steels. Adapting and setting up the machine for casting different alloys and/or different billet sizes require a little time, no more than 20 minutes.
查看更多>>摘要：The problem of flow and heat transfer over a continuously stretching surface finds applications in many manufacturing processes, such as polymer extrusion, wire drawing, continuous casting, glass fiber production, and metallurgical processes. It is known that the properties of the final product depend considerably on the rate of cooling during the manufacturing processes. The rate of cooling can be controlled by drawing the strips in an electrically conducting fluid subject to a magnetic field, so that a final product of desired characteristics can be achieved. In this study, the problem of magneto-hydrodynamic (MHD) mixed convective flow and heat transfer of an electrically conducting fluid past a stretching surface under the influence of an applied magnetic field is analyzed. After transforming the governing equations with suitable dimensionless variables, numerical solutions are generated by an implicit finite-difference technique for the non-similar, coupled flow. To reveal the tendency of the solutions, typical results for the velocity and temperature profiles, the skin-friction coefficient, and the local Nusselt number are presented for different parameters.
查看更多>>摘要：This paper explores the inspection allocation problem with considering production line balance at the same time for multi-station assembly systems. A mathematical model is developed in order to find the minimal total cost. When the number of parts increases, the time spent increases dramatically with the enumerative method. Therefore, an approach to genetic algorithm is developed and it takes much less time with near-optimal solutions.
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