Advanced Materials Research Vols. 156-157

Abstract: Parts information of steel bridge with tens of thousands of parts is difficult to be managed and be executed statistics. On the platform of three-dimensional CAD systems, steel bridge node is the study object in this paper, according to the assembly relationship of all parts in the three-dimensional assembly model, the parts list, quantity, geometrical information and weight of the parts of the steel bridge nodes are extracted from a three-dimensional model by the application interface provided by three-dimensional CAD systems. On the basis of geometrical information of the parts, the minimum boundary dimension of the parts is computed by use of the principle of computer graphics. The method can rapidly and accurately obtain parts information, and can provide basis for assembly process and processing technology.

Abstract: It is important to build the models for calculating the cutting-forces in high-speed machining, but it is difficult as the special test-bed with the cutting-force measurement system is complicated, cost much and cannot be applied directly on general machining tools. Aiming at the problems above, a new method was put forward about cutting-force modeling based on the current of high-speed electric spindles, in which the cutting-force models could be gained indirectly by analyzing the built-in motor current and the data gotten from cutting experiments on those general machining tools which are installed with electric spindles. Then on a vertical milling machine tool which is equipped with a high-speed electric spindle, a model for calculating the milling force was gotten using the method put forward by this paper. The results show that the method is simple and easy to be used in routine machine tools in plant spots and need no any special test-beds and any complicated measurement systems possessed only in the laboratory conditions.

Abstract: Circle, line and circular arc are the common basic elements in industrial computed tomography (ICT) image. The algorithm of recognizing such elements is the key to industrial CT image precise vectorization. An industrial CT image vectorization system has been studied, including different recognition methods for these elements. Firstly, based on facet model, the sub-pixel edge of an industrial CT image is extracted. Then, the circles are recognized by an improved algorithm based on probability of existence map, while the lines are recognized with the set intersection algorithm of fitting a straight line, and the circular arcs are recognized by the combination of the perpendicular bisector tracing algorithm and least squares function. Finally, the element parameters are measured according to recognition results, and the drawing exchange file (DXF) is produced and transmitted into the computer aided design (CAD) system to be edited and consummated. The experimental results show that these methods are capable of recognizing graphic elements in industrial CT image with an excellent accuracy, besides, the absolute errors of circles are less than 0.1 mm, the relative errors are less than 0.5%. It can satisfy the industrial CT vectorization requirements of higher precision, rapid speed and non-contact.

Abstract: In order to meet the requirements of product design and find suitable combination of within a short time, the concept of Knowledge-body based on BOM (KBOM) was put forward, which consisted of basic entities that could support all activities throughout product lifecycle with less redundancy, and all the product data throughout product lifecycle was associated with the core of KBOM directly or indirectly. A reusable and sharable configuration model of product was established to represent domain-specific knowledge based on KBOM. Genetic algorithm was used to solve the issue concerned with BOM configuration in a short time with value coefficient, quality level and reliability as evaluation parameters. Finally, as a case study, the display module of a notebook was analyzed. The results indicate that the evaluation can be effectively applied in a large-scale BOM configuration.

Abstract: In order to obtain the effect of fibers on fractural property of mass concrete, it had investigated physical performance, elastic modulus and bending toughness of mass concrete with the presence of steel fiber and polypropylene fiber(PPF). Results showed that the inclusion of PPF caused a slight decrease in initial cracking strength, flexural strength and elastic modulus, yet resulted in small increase in equivalent flexural strength, capacity-carrying loading variation coefficient and toughness.The presence of steel fiber was of significance to increase initial-cracking strength, flexural strength and equivalent flexural strength, and produced a slight increase in elastic modulus and significant improvement in capacity-carrying variation coeffecient and flexural toughness. Overall, the inclusion of steel fiber is rated better than PPF in improving ductility and crack resistance of concrete.

Abstract: The increase of container shipment causes higher demand on the seaport container terminals, container logistics and management. How to rationally allocate the limited space resources and how to improve operational efficiency, is an important subject for container terminals. In this paper, the mathematical modeling and optimization on yard allocation planning based on the mixed storage is proposed with an objective to balance the workload among different blocks and to minimize the delay of container ships. Two corresponding heuristic algorithms are developed to solve this problem. The experimental results show that the proposed algorithms are the promising tool for allocating blocks’ workload.

Abstract: Cellular Manufacturing is taken into account with advancing of the production mode of multi-product and small batch. Cellular Manufacturing includes cell foramtion, machine layout and cellular layout. Most researchers are foucing on the three contents respectively in their previous research. But these three contents are co-relation and the change in one content will affect the others and the result. So the integration mathmatical model of the cell formation, machine layout and cellular layout is put forward in this paper to abtain the minmum of material movement handling cost and machine depreciable and repair cost. At last this paper applies the model to machining workshop of XXX Company and gains a good effection.

Abstract: Cantilever installation is a construction method of which is often used in the construction of Concrete Oblique-pulling truss bridge. For ensuring the safety of construction process, the structural line shape and stress under different construction phases of the bridge were tested. Contrastive analysis between the testing results and the calculating results was carried on in different construction phases. The results showed the testing values of vertical displacement is smaller than the calculating values because the actual stiffness of the structure is bigger than the theory stiffness. But the stress of key section’s stress of the truss bridge in the whole construction phases agreed pretty well between the testing results and the calculating results. The maximal cantilever length phase to entire bridge closure phase is the most disadvantageous state in the whole construction process.

Abstract: The vibration energy dissipation theory of a self-force-amplifier dry friction damper has been discussed detail in this paper. The research shows that the new dampers have traditional dampers’ merit and overcome their shortcoming which can only offer invariable friction. At the same time, they can be feedback controlled by the displacement signals of the controlled structure. So the ability of energy dissipation and vibration control effect of the new damper can be augmented.

Abstract: Automotive transmission is one of the key components of automotive, and the design quality of transmission can affect the driving performance, fuel consumption and serve life of vehicle greatly, therefore it is very important to design planetary transmission of vehicle. Genetic algorithm can seek parallelized different regions of the whole parameter space in the progress of its replacement, and make a progress towards being possible to find optimum global solution. The planetary transmission is designed by the minimum volume of objective optimization, and considering loading property and material quality, the constraints are set up. Combination of genetic algorithm and SQP is adopted to solve optimization model. So the AMT have a more compact structure. and vehicle passing performance can be improved and vehicle equipment mass be reduced.