Applied Mechanics and Materials Vols. 10-12

Abstract: Job-shop dynamic scheduling is an important subject in the fields of production management and combinatorial optimization. It is usually hard to achieve the optimal solution with classical methods due to the high computational complexity of the problem. A solution of job-shop scheduling problem based on multi-agent is presented for the comparability between the dynamic scheduling problem of job-shop production and the TSP problem. The dynamic scheduling of job-shop production is designed according to the pattern of TSP problem which can be applied with ACO. By the application case, the ACO is the new method to solve the dynamic scheduling of job-shop production.

Abstract: Considering the complexity and uncertainty of production planning in large manufacturing enterprise, hierarchical planning and scheduling is an effective solution to overcome the difficulty of scheduling both in long term and short term. Choosing a discrete task-oriented manufacturing factory as prototype, a hierarchical planning and scheduling model is developed, which consists of key resource leveling, detailed operation scheduling and workshop control. The upper level optimizes the bottleneck resource allocation based on aggregate networks of product, to make a feasible long term plan; short term schedule is then generated in medium level, using more detailed network; the schedule is finally executed in bottom level, which introduces a re-scheduling strategy to eliminate the plan error. To solve the model, the universal aggregate task network model and the algorithm for each level are researched. The simulation result demonstrated that the hierarchical method is valid and valuable in practice.

Abstract: In the light of project management, concurrent engineering and agile manufacturing, in relation to the characteristics of the concurrence of developing and batch manufacturing, this text studies the hierarchical information technology of the production management system based on project driving. The operation flow of project-driven hierarchical information system of production management has been designed and implemented. The soft architecture and operating model have been proposed. The coordinating and controlling model based on workflow, queuing theory, and the capability balancing method are established.

Abstract: This paper starts with an analysis of the need for knowledge based engineering (KBE) system based on typical domain-specific engineering products. It looks back the history of KBE and exams the general structure of KBE systems. It then reviews the current development, particularly the knowledge representation in a KBE system, followed by a discussion of the shortcomings regarding to the maintenance and excessive cost of integrations with other digital tools. Finally it recommends the characteristics of a genuine KBE system and the standardization of KBE applications, particularly the internal knowledge representation standards and knowledge-based system interface standards with CAx systems and PLM solutions.

Abstract: The technology of product configuration in a Product Data Management (PDM) system was discussed in this paper. The paper presented the product configuration modeling technology by based on the ‘and/or’ tree of product configuration, the process relation and coupling relation between components, and then, a general model of the product configuration scheme was proposed. The product configuration algorithm based on the product configuration scheme was also introduced and the feasibility from the theory model to the program was proved. The paper also discussed the application of Case-Based Reasoning(CBR) technology in product configuration, and, the emphasis was given towards the similar component search by the Nearest Neighbor(N-N) method. Finally, the product configuration technology was implemented on hydro-generator design process, and the result indicated this technology was valuable to realize intelligentization and automation of product configuration.

Abstract: To explore geometrical shape deforms, stress distribution, strain distribution and wall thickness of products in the process of polycarbonate (PC) hot gas pressure bulging, numerical simulation of 1mm thick hemispherical PC part with a diameter of 100mm has been conducted by the software of DYNAFORM. The result shows that abrupt changes tend to occur in the deforming of PC sheet as the even loaded pressure increases to a given point. A critical circle exists in the photoelastic experiment of latitude strain distribution, wall thickness distribution and displacement change, thus making the wall thickness of hemispherical part become gradually thick from critical circle part to pressure-pad-circle part. Importantly the experimental result fits well with the finite element analysis.

Abstract: In the light of growing global competition, organizations around the world today are constantly under pressure to produce high-quality products at an economical price. The integration of design and manufacturing activities into one common engineering effort has been recognized as a key strategy for survival and growth. Design for manufacturability (DFM) is an approach to design that fosters the simultaneous involvement of product design and process design. The implementation of the DFM approach requires the collaboration of both the design and manufacturing functions within an organization. At present, For some reasons DFM approach is ineffectively including lack of interdisciplinary expertise of designers; inflexibility in organizational structure, which hinders interaction between design and manufacturing functions. Design for manufacture is the practice of designing products with manufacturing in mind. Early consideration of manufacturing issues can shorten product development cycle time, minimi overall development cost and ensure a smooth transition into production. In this paper, part manufacturability under Concurrent Engineering (CE) environment was analyzed in detail. An evaluation system of DFM was proposed according to CE ideas. A fuzzy set-based manufacturability evaluation algorithm is formulated to generate relative manufacturability indices to provide product designers with a better understanding of the relative ease or difficulty of machining the features in their designs. An analytic hierarchy process (AHP) method is introduced to assign weighting factors to features to reflect their functional importance. Results from the case studies show the method available and practicable.

Abstract: On the basis of analysis and summary of the research of the others, we choose the notepad as the carrier of the data file and a code as the expression of the feature information of the products, embedding them in the 3D CAD system like a plug-in unit. In this way, the products’ data accurate transmission between distributed and isomeric CAD systems over the internet is realized. This method can also be used in the real-time collaborative design system.

Abstract: Complex products are integrated by many subsystems through complex couplings. It is fussy to do design optimization on complex product in traditional mode. In this paper, a new design optimization process is illustrated based MDO technology. First, the traditional design optimization process of complex product is analyzed. And then, the MDO techniques are introduced. Using the MDO techniques, we conclude a new design optimization process which can improve the efficiency and the steps of this process is illustrated.

Abstract: In order to automate the manufacturing process design and shorten the design lifecycle, a visible manufacturing process design system is put forward. In this system, the workflow technology is used to manage the procedure of manufacturing process design. In this paper, a typical procedure of manufacturing process design is analyzed. Based on this analysis, the structure of the system and the interfaces to each other are also introduced. Furthermore the key technologies that are needed in actualizing the system are analyzed, and an application of this system is provided.