Applied Mechanics and Materials Vols. 44-47

Abstract: Under the circumstance of disruptive demand, the decision-making and coordination of enterprise’s capacity is directly related to the efficiency of supply chain operation. On the basis of the baseline case, capacity reservation contract sees that the performance of decentralized supply chain is equal to the centralized supply chain, and better than the level of the optimal supply chain capacity under the wholesale price contract. For disruptive demand, this paper discusses the conditions of capacity expansion and supply chain coordination through the capacity reservation contract in two cases, i.e., symmetric disruptive information, asymmetric disruptive information, and compares the optimal capacity and the corresponding profit.

Abstract: This paper presents a Manufacturing Execution System (MES) for the composite component manufacturing workshop of an aerospace enterprise. The production process management is the core module of the MES. The system shows the production process management has important effect on the workshop production. The function modules of the production process management are introduced in detail. An improved working flow of the production process for optimizing the traditional production process is emphatically described. Barcode technology is applied to collect the production data and quality inspection data. By scanning the barcode, the real time data information can be collected and data statistic analysis can be done rapidly. The integration relationship between the production process management system and other systems is also introduced. Three-layer structure is adopted to design and develop the system. The developed system has been applied in the composite component manufacturing workshop. The results show that working efficiency of production process management has been improved.

Abstract: Aiming at the characteristics of optional disassembly problem, disassembly strategy based on bionic disassembly hive model is presented in this study. This method is combined with modular theory to resolve the data explosion which is caused by too many parts in disassembly body for relevant algorithms. Through establishing disassembly hive space model, the judgment of disassembly direction and some other problems are transferred into the evaluation of ant bee groups’ migration routes. The relative disassembly difficulty of the part is defined based on the conception of disassembly ring. And new ideas of obtaining disassembly sequence are introduced to improve the efficiency of getting disassembly programs.

Abstract: Based the principle of online dynamic balance device with balancing disks, the design method of embedded double-face online dynamic device was proposed. Balancing disks could be disengaged from the spindle by Hydraulic system, and the rotating speed of the disengaged disk was kept steady and under the speed of the spindle by friction torque. The systems of signal acquisition, signal analysis and control, hydraulic pressure were designed. The feasibility was proved and analyzed by examples.

Abstract: There are many kinds of casting defects such as insufficient pouring, cooling separation, crack, and shrinkage and soon on were formed in the mold filling and the solidification process, which affect the final casting performance. Based on the mathematical models of mold filling and solidification process, the numerical simulation of chilled cast iron camshaft in sand casting process has been done. The filling behaviors at each stage in the filling process were presented. The temperature distributions in the solidification process were obtained, and the positions of shrinkages were predicted. According to the simulation results, an improved technology is proposed, and the shrinkages were eliminated efficiently. The simulation results are in good agreement with practical.

Abstract: The physical, mathematical and finite element model of the extruding part of mixing-extruding machine was established to carry on the finite element simulation of the extrusion part flow field. Results showed that the double cone screw have better mixing and feeding properties than single screw.

Abstract: VIC mixer was a new type mixing equipment, and both had internal mixer's and open mixer's advantages. Meshing clearance of VIC mixer can be changed in the mixing process at any time by the eccentric bearing. The meshing clearance can be changed at different stages of the mixing process to adjust the different mixing formula and process. Through the experiments we had found that VIC mixer have a good mixing temperature control, cooling efficiency and low peak value in power when the meshing clearance is small. When the meshing clearance is large there is a high feeding speed, energy utilization efficiency and dispersion.

Abstract: Flexible roll forming is a new forming process that produces parts with variable cross sections. This forming process is proposed to meet the need in the weight reduction of automobiles. With deep understanding of this process and reasonable simplification, the FEM model of a nine-step flexible roll forming of an ultra-high-strength steel bumper is established. In order to analyze the mechanics and the deformation characteristics of the flexible roll forming, equivalent stress, equivalent strain, sheet thickness and springback amount are extracted from the simulation result and studied comparatively, which is of great importance to understand the appearance of the forming defects. In addition, the forming load and torque of the rollers can also be obtained which can guide the design of the flexible roll forming product line.

Abstract: The resource restrict in product development processes greatly influences on the cost and progress of the whole project. In this paper, a task priority algorithm that can solve the problem of resource competition, taking the related theory of project management into consideration comprehensively, is proposed. A flexible model of product development process is described based on hierarchical colored Petri net. And then a resource coordination mechanism is modeled according to the characteristic of modern product development processes. Finally, a resource allocation process is analyzed and optimized in order to enhance the utilization efficiency of resource and to shorten the product development time.

Abstract: In this study, the springback law of generatrix direction, circumferential direction of tailor welded blanks (TWBs) cylinder shallow shell impact from blank holder force, punch profile radius and sheet thickness was researched by finite element analysis, which was compared with non-welded blanks. The results show that: in the circumferential direction, with the increase of blank holder force, the trimming springback of the tailor welded blank of the thickness combination of 1.2mm and 0.8mm (TWB1208) is decreased firstly and then increased, which is larger than that of the non-welded blanks of 0.8mm and 1.2mm. With the increase of punch profile radius, the drawing and the trimming springback of TWB1208 are both increased, and after trimming, the both springback are greater than that of the non-welded blanks. With the increase of the quadratic difference of thickness, TWB1208, TWB1612 and TWB1608, the drawing springback is decreased, and the trimming springback is gradually increased. In the generatrix direction, when blank holder force is less, the distortion deformation of TWBs is serious, and after the trimming, it is decreased according to the increasing blank holder force. With the increase of punch profile radius, the distortion deformation is larger. The greater the difference of thickness is, the more serious the distortion deformation is.