Advanced Materials Research Vols. 941-944

Abstract: Considering the feature of roller capacity with dynamics change in round bar production, a hot-rolling batch planning problem is studied. Firstly, the problem is formulated as a different capacities vehicle routing problem (DCVRP). And then, a mathematic model is built with two optimization objectives, minimization for total set-up time and maximization for utilization of roller. Secondly, an algorithm based on constraint satisfaction technique is present with variable selection rules and value selection rules for billet selecting, grouping and sequencing, and constraint propagation for searching-space reducing and rolling-unit partitioning. Meanwhile, the current capacity of online roller is updated dynamically during the solving process of algorithm. Finally, comparing results indicated that the proposed model and algorithm are effective and efficient.

Abstract: This paper presents the influence of modeling and simulation techniques for hard milling and forming. The aim of these simulations is the ability to optimize the manufacturing technologies even before the real production of its own tools, because their manufacturing process is very difficult in terms of production time, materials and other costs. The simulated results visualize roughing and finishing process of milling and generate tool-paths in CATIA V5. Simulation results of forming realized in PAM-Stamp 2G using a 3D model of the punch and the blank confirm the suitability of the proposed design of the forming tool. Finally, hard milling and forming simulations in CAE systems CATIA V5 and PAM-Stamp 2G were performed in order to determine and evaluation of suitability of the proposed shapes of the forming tool.

Abstract: Considering the extrudate swell, the polymer extrusion process was calculated by the inversed simulation based on the visco-elastic ecology theory. The fluid characteristics of the polymer melt were described by the Phan-Thien and Tanner (PTT) model. The Finite Element Method was used. Based on the simulation data, the extrusion die lips were analyzed. So it is feasible to design the polymer extrusion die lips using inversed simulation method.

Abstract: A challenging problem in the numerical simulation of a self-contacted elastic rod is the change of topological structure during the contacting process. In this article, a numerical approach is introduced to simulate a self-contacted Cosserat rod. By introducing the angular velocity and Euler parameters as the state variables, an improved Lagrange equation is introduced. A finite element method is built to deal with the simplified model, and numerical examples are given.

Abstract: In this paper, a Schwarz alternating algorithm using elliptical arc artificial boundary for boundary value problem of Poisson equation in an infinite domain with a concave angle is investigated. The convergence of this algorithm is given. The convergence rate is analyzed in details for a typical domain. Finally, some numerical examples are presented to show effectiveness of our method.

Abstract: Based on statistics theory and contact theory, a material removal model for predicting polishing quality in chemical-mechanical polishing (CMP) of multi-material surface is developed. The contacts of pad-workpiece and pad-particle-workpiece are characterized by the elastic–plastic contact mechanism. The material removal is considered to be the sum of the contributions from two movement modes of particles. Within the model, linear material removal volume (LMRV) can be determined as a function of the interactions of workpiece, pad and slurry. The model also determines the relationship between LMRV and roughness. It is found that polishing pad and parameters of polishing conditions have significant effects on the polishing quality. The experimental results show that chemical reagents contribute quite differently to multi-material end-face planarization. The proposed model reveals insights into improvement of the polishing quality of multi-material surface such as fiber array end-face.

Abstract: Splitting spinning is a special spinning processing method which is different from the common spinning and powerful spinning. According to the forming step can be divided into splitting process and shaping process. It analyzed splitting spinning process of deformation behavior by the elastic plastic finite element method of 2024 aluminum alloy, it determined the largest area of deformation and stress concentration region in the deformation process of the deformation, at the same time, it proposed the adaptive grid technique in splitting spinning simulation process, and selected quality amplification factor carefully.

Abstract: FLUENT was used to simulate the propellant flow law in the flow channel of a seven-hole propellant die, and distributions of internal pressure, velocity fields was obtained. The influence of compression ratio, temperature and flow rate was analyzed. The results show that compression ratio influences the pressure and velocity distribution obviously. In addition, flow temperature and inlet rate have a small effect on pressure and velocity distribution.

Abstract: During the last decades, automotive industry has to meet many environmental constraints and to reduce the cost and the energy conception. Giving their mechanical properties and low manufacturing cost, thermoplastic multilayered materials have proven to be an adequate solution for such applications. In this paper, the particular combination of Thermoplastic PolyOlefin (TPO) sheets and Polypropylene (PP) foams is considered. The mechanical behavior of each material is studied and the multilayered material response is predicted and compared to measurements at a 120°C temperature. Despite the transversely isotropic behavior of the TPO sheets and the very high stretch ranges, the obtained results are very convincing and the used models proved to be very reliable.

Abstract: The angle of repose of sand pile compose of cylindrical particles was extensively studied using the discrete element method (DEM). The Multi-element model was selected for representing cylindrical particle and the effects of shape of granular on angle of repose were studied. The results show that the angle of repose of cylindrical particles is obviously larger than that of spherical particles. Meanwhile, the shape factor (length-width ratio) of cylindrical granular has a great influence on the angle of repose of granular system. As studied in this paper, the angle of repose increases with the increasing of length-width ratio. Cautious should be taken when choosing a reasonable particle model for more precise DEM results.