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Mold Filling (mold + filling)
Selected AbstractsNumerical simulation of three-dimensional free surface flowsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 7 2003V. Maronnier Abstract A numerical model is presented for the simulation of complex fluid flows with free surfaces in three space dimensions. The model described in Maronnier et al. (J. Comput. Phys. 1999; 155(2) : 439) is extended to three dimensional situations. The mathematical formulation of the model is similar to that of the volume of fluid (VOF) method, but the numerical procedures are different. A splitting method is used for the time discretization. At each time step, two advection problems,one for the predicted velocity field and the other for the volume fraction of liquid,are to be solved. Then, a generalized Stokes problem is solved and the velocity field is corrected. Two different grids are used for the space discretization. The two advection problems are solved on a fixed, structured grid made out of small cubic cells, using a forward characteristic method. The generalized Stokes problem is solved using continuous, piecewise linear stabilized finite elements on a fixed, unstructured mesh of tetrahedrons. The three-dimensional implementation is discussed. Efficient postprocessing algorithms enhance the quality of the numerical solution. A hierarchical data structure reduces memory requirements. Numerical results are presented for complex geometries arising in mold filling. Copyright © 2003 John Wiley & Sons, Ltd. [source] Numerical simulation of mold filling in injection molding using a three-dimensional finite volume approachINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2001Rong-yeu Chang Abstract This work presents an implicit finite volume approach to simulate the three-dimensional mold filling problems encountered during the injection molding. The described numerical model deals with the three-dimensional isothermal flow of incompressible, high-viscous Newtonian fluids with moving interfaces. The collocated finite volume method and the SIMPLE segregated algorithm are used to discretize and solve the Navier,Stokes equation. In addition, a bounded compressive high-resolution differencing scheme is adopted to solve the advection equation to capture the interface on a Eulerian framework. This approach effectively solves the flow field in terms of CPU time and memory storage as well as the complicated three-dimensional melt front topology. Several two- and three-dimensional examples are presented to validate the presented approach and illustrate its capabilities. This method can more accurately predict the critical three-dimensional phenomena encountered during mold filling than the existing Hele,Shaw analysis model. The presented numerical approach has been proven to be a highly effective and flexible tool for simulating mold filling problems. Copyright © 2001 John Wiley & Sons, Ltd. [source] Simulation of Ni3Al-based Alloy and Investment Casting Process of its Thin Wall CastingsISRAEL JOURNAL OF CHEMISTRY, Issue 3-4 2007Xi-e Zhang It is very difficult to produce thin wall complex castings of the Ni3Al-based alloy by investment casting. Defects such as incomplete mold filling and hot tears appear commonly. In this paper, physical parameters of Ni3Al-based alloy are obtained by experiments and simulations using JmatPro software. The calculation results of physical parameters are credible by comparing with test results and can be used in the pre-processing of casting simulaton software ProCAST of thin wall castings. Gating and feeding system is optimized to decrease hot tearing tendentiousness and ensure filling ability according to casting simulation results. [source] Profiling of injection velocity for uniform mold fillingADVANCES IN POLYMER TECHNOLOGY, Issue 1 2006Xi Chen Abstract Uniform melt front velocity is recommended for injection mold filling to minimize the part nonuniformity. A method of profiling the injection velocity for such a uniform mold filling is presented in this paper. Based on a neural network model developed for estimating the melt flow length from online measurable variables, the profiling problem is transformed into an optimization to minimize the difference between the predicted melt flow length and a given ramp. The rate of the ramp determines the rate of the melt front velocity traveling in the cavity during filling. Experiments with different molds show that the proposed method is effective in profiling the screw injection velocity to achieve a uniform mold filling. © 2006 Wiley Periodicals, Inc. Adv Polym Techn 25: 13,21, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20054 [source] Reactive mold filling in resin transfer molding processes with edge effectsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009Yanyu Ding Abstract Reactive mold filling is one of the important stages in resin transfer molding processes, in which resin curing and edge effects are important characteristics. On the basis of previous work, volume-averaging momentum equations involving viscous and inertia terms were adopted to describe the resin flow in fiber preform, and modified governing equations derived from the Navier,Stokes equations are introduced to describe the resin flow in the edge channel. A dual-Arrhenius viscosity model is newly introduced to describe the chemorheological behavior of a modified bismaleimide resin. The influence of the curing reaction and processing parameters on the resin flow patterns was investigated. The results indicate that, under constant-flow velocity conditions, the curing reaction caused an obvious increase in the injection pressure and its influencing degree was greater with increasing resin temperature or preform permeability. Both a small change in the resin viscosity and the alteration of the injection flow velocity hardly affected the resin flow front. However, the variation of the preform permeability caused an obvious shape change in the resin flow front. The simulated results were in agreement with the experimental results. This study was helpful for optimizing the reactive mold-filling conditions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Modeling and simulation approaches in the resin transfer molding process: A reviewPOLYMER COMPOSITES, Issue 4 2003A. Shojaei A review of current approaches in modeling and simulation of the resin transfer molding (RTM) process is presented. The processing technology of RTM is discussed and some available experimental techniques to monitor the process cycle are presented. A master model is proposed for the entire process cycle consisting of mold filling and curing stages. This master model contains the fundamental and constitutive sub-models for both stages. The key elements of the master model discussed in this study are: flow, heat and mass balance equations for fundamental sub-models, permeability, cure kinetics, resin viscosity and void formation for constitutive sub-models. At the end, numerical methods widely used to simulate the filling process are presented and published simulation results of mold filling and process cycle are reviewed. [source] Analysis of the vacuum infusion molding processPOLYMER COMPOSITES, Issue 1 2000A. Hammami The vacuum infusion molding process is becoming increasingly popular for the production of large composite parts. A comprehensive model of the process has not been proposed yet, making its optimization difficult. The flexible nature of the vacuum bag coupled to the varying pressure inside the mold cavity results in a variation of the cavity thickness during the impregnation. A complete simulation model must incorporate this phenomenon. In this paper, a complete analysis of the vacuum infusion molding process is presented. The analysis is not restricted to the theoretical aspects but also reviews the effect of the main processing parameters. The parameters investigated in this paper are thought to be those of most interest for the process, i.e. the compaction of the reinforcement, the permeability, the infusion strategy and the presence of flow enhancement layers. Following the characterization experiments, a 1-D model for the vacuum infusion molding process is presented. This model is derived assuming that an elastic equlibrium holds in the mold cavity during mold filling. Even though good agreement was found between simulation results and experiments, it is concluded that additional work is needed on the numerical model to integrate interesting findings from the experimental part. [source] Three-dimensional numerical simulation of injection molding filling of optical lens and multiscale geometry using finite element methodPOLYMER ENGINEERING & SCIENCE, Issue 9 2006Sang-Woo Kim This article presents the development, verification, and validation of three-dimensional (3-D) numerical simulation for injection molding filling of 3-D parts and parts with microsurface features. For purpose of verification and comparison, two numerical models, the mixed model and the equal-order model, were used to solve the Stokes equations with three different tetrahedral elements (Taylor-Hood, MINI, and equal-order). The control volume scheme with tetrahedral finite element mesh was used for tracking advancing melt fronts and the operator splitting method was selected to solve the energy equation. A new, simple memory management procedure was introduced to deal with the large sparse matrix system without using a huge amount of storage space. The numerical simulation was validated for mold filling of a 3-D optical lens. The numerical simulation agreed very well with the experimental results and was useful in suggesting a better processing condition. As a new application area, a two-step macro,micro filling approach was adopted for the filling analysis of a part with a micro-surface feature to handle both macro and micro dimensions while avoiding an excessive number of elements. POLYM. ENG. SCI., 46:1263,1274, 2006. © 2006 Society of Plastics Engineers [source] | |||||||||||||