The Experts below are selected from a list of 8202 Experts worldwide ranked by ideXlab platform

Chensong Dong - One of the best experts on this subject based on the ideXlab platform.

  • A modified rule of mixture for the vacuum-assisted resin transfer Moulding Process simulation
    Composites Science and Technology, 2008
    Co-Authors: Chensong Dong
    Abstract:

    The vacuum-assisted resin transfer Moulding Process (VARTM) offers many advantages over the traditional resin transfer Moulding such as lower tooling cost, room temperature Processing. Computer simulation has become a powerful tool for liquid composite Moulding Process design and optimisation. In the VARTM Process simulation, due to the presence of HPM and flow channels, the conventional simulation will require 3-D geometric model and mesh generation. The extensive computation load and complexity of pre-Processing limit the usage of simulation in the Process design and optimisation. In this paper, a two-step method for improving the efficiency of VARTM Process simulation is presented. First, a design of experiment approach was coupled with 2-D CVFEM (control volume finite element method) simulation to calculate the equivalent permeability and porosity for various Process variable combinations. Based on the data from DOE, a modified rule of mixture for calculating the equivalent permeability and porosity was developed, with which the mould filling can be simulated in 2-D. Second, the algorithm for the through-thickness flow front construction was developed. The presented method was validated by comparing the result against that from the 3-D simulation. It shows that the accuracy is within 5% while the computation time saving is over 99%.

  • A modified rule of mixture for the vacuum-assisted resin transfer Moulding Process simulation
    Composites Science and Technology, 2008
    Co-Authors: Chensong Dong
    Abstract:

    The vacuum-assisted resin transfer Moulding Process (VARTM) offers many advantages over the traditional resin transfer Moulding such as lower tooling cost, room temperature Processing. Computer simulation has become a powerful tool for liquid composite Moulding Process design and optimisation. In the VARTM Process simulation, due to the presence of HPM and flow channels, the conventional simulation will require 3-D geometric model and mesh generation. The extensive computation load and complexity of pre-Processing limit the usage of simulation in the Process design and optimisation. In this paper, a two-step method for improving the efficiency of VARTM Process simulation is presented. First, a design of experiment approach was coupled with 2-D CVFEM (control volume finite element method) simulation to calculate the equivalent permeability and porosity for various Process variable combinations. Based on the data from DOE, a modified rule of mixture for calculating the equivalent permeability and porosity was developed, with which the mould filling can be simulated in 2-D. Second, the algorithm for the through-thickness flow front construction was developed. The presented method was validated by comparing the result against that from the 3-D simulation. It shows that the accuracy is within 5% while the computation time saving is over 99%. © 2008 Elsevier Ltd. All rights reserved.

  • Assembly dimensional variation modelling and optimization for the resin transfer Moulding Process
    Modelling and Simulation in Materials Science and Engineering, 2004
    Co-Authors: Chensong Dong, Zhiyong Liang, Chuck Zhang, Ben Wang
    Abstract:

    The optimization for resin transfer Moulding Process and assembly dimensional variation modeling was studied. A dimensional variation model was developed for Process simulation based on thermal stress analysis and FEA. Data were collected by varying the designed geometric parameters. The structural tree method (STM) was proposed to compute the assembly deformation from individual components. The regression-based dimensional variation model provides a quick guide for composite product design.

Q. P.v. Fontana - One of the best experts on this subject based on the ideXlab platform.

  • Viscosity: thermal history treatment in resin transfer Moulding Process modelling
    Composites Part A-applied Science and Manufacturing, 1998
    Co-Authors: Q. P.v. Fontana
    Abstract:

    Thermal history dependent viscosity models have been used in various numerical codes to predict the variation of the resin viscosity during the resin transfer Moulding Process (RTM). The models are based on mathematical models which predict the degree of cure of the resin and then use this to predict the viscosity. The work presented in this paper illustrates some of the difficulties associated with thermal history dependent viscosity modelling for RTM and highlights sources of variation between the behaviour predicted from these models and the real behaviour of the resin. An alternative method is outlined and demonstrated which may circumvent many of the current problems and sources of inaccuracy.

  • Viscosity: Thermal history treatment in resin transfer Moulding Process modelling
    Composites Part A: Applied Science and Manufacturing, 1998
    Co-Authors: Q. P.v. Fontana
    Abstract:

    Thermal history dependent viscosity models have been used in various numerical codes to predict the variation of the resin viscosity during the resin transfer Moulding Process (RTM). The models are based on mathematical models which predict the degree of cure of the resin and then use this to predict the viscosity. The work presented in this paper illustrates some of the difficulties associated with thermal history dependent viscosity modelling for RTM and highlights sources of variation between the behaviour predicted from these models and the real behaviour of the resin. An alternative method is outlined and demonstrated which may circumvent many of the current problems and sources of inaccuracy. © 1997 Elsevier Science Limited.

Ben Wang - One of the best experts on this subject based on the ideXlab platform.

  • Assembly dimensional variation modelling and optimization for the resin transfer Moulding Process
    Modelling and Simulation in Materials Science and Engineering, 2004
    Co-Authors: Chensong Dong, Zhiyong Liang, Chuck Zhang, Ben Wang
    Abstract:

    The optimization for resin transfer Moulding Process and assembly dimensional variation modeling was studied. A dimensional variation model was developed for Process simulation based on thermal stress analysis and FEA. Data were collected by varying the designed geometric parameters. The structural tree method (STM) was proposed to compute the assembly deformation from individual components. The regression-based dimensional variation model provides a quick guide for composite product design.

Kyle Jiang - One of the best experts on this subject based on the ideXlab platform.

  • a soft Moulding Process for manufacture of net shape ceramic microcomponents
    The International Journal of Advanced Manufacturing Technology, 2010
    Co-Authors: Hany Hassanin, Kyle Jiang
    Abstract:

    A soft Moulding Process for manufacture of ceramic microcomponents, alumina and Al2O3/SiC composite, is introduced in this paper. The Process involves fabrication of SU-8 master moulds and production of mirrored polydimethysiloxane (PDMS) soft moulds. Green parts are formed in the PDMS moulds by filling the ceramic slurry into the soft moulds and net-shape green components are obtained after deMoulding. The methods for the mould filling using different suspensions were demonstrated: one was aqueous suspension for alumina microcomponent and another was non-aqueous suspension for Al2O3/SiC microcomponent. The measurements showed that the proposed soft lithography Process is successful in producing ceramic microcomponents and retaining the fine features in micron scale.

  • A soft Moulding Process for manufacture of net-shape ceramic microcomponents
    International Journal of Advanced Manufacturing Technology, 2010
    Co-Authors: Zhigang Zhu, Hany Hassanin, Kyle Jiang
    Abstract:

    A soft Moulding Process for manufacture of ceramic microcomponents, alumina and Al2O3/SiC composite, is introduced in this paper. The Process involves fabrication of SU-8 master moulds and production of mirrored polydimethysiloxane (PDMS) soft moulds. Green parts are formed in the PDMS moulds by filling the ceramic slurry into the soft moulds and net-shape green components are obtained after deMoulding. The methods for the mould filling using different suspensions were demonstrated: one was aqueous suspension for alumina microcomponent and another was non-aqueous suspension for Al 2O3/SiC microcomponent. The measurements showed that the proposed soft lithography Process is successful in producing ceramic microcomponents and retaining the fine features in micron scale. © 2008 Springer-Verlag London Limited.

Valerio Brucato - One of the best experts on this subject based on the ideXlab platform.

  • On the Simulation of Thermoplastic Injection Moulding Process TL - 12
    Hanser Verlag, 1997
    Co-Authors: Giuseppe Titomanlio, Vito Speranza, Valerio Brucato
    Abstract:

    Abstract The relevance of enhancement of crystallisation kinetics by effect of shear flow and rheology during polymer solidification to the phenomena taking place during the injection Moulding Process has been shown by means of simulations performed on the basis of Lord and Williams [1, 2] model and its recent extensions [3 to 5]. A key point of the simulation was the solidification criterion based on a critical crystallization index; on the basis of simple calorimetric and rheological tests in the limit of zero shear rate, values of a few percent were given to the solidification crystallinity value. Many experimental features of pressure history both in the runner and in the cavity are recovered by model predictions, if both effects mentioned above are properly accounted for. However, predictions for gate sealing time, although improved, still have a sensitivity to gate thickness lower than that shown by the experiments. Similar conclusions, obviously, regard also the mass entering in the mould during holding. Another mechanism which sums up to shear stresses to accelerate thin gate solidification has still to be identified.

  • On the Simulation of Thermoplastic Injection Moulding Process
    International Polymer Processing, 1995
    Co-Authors: Giuseppe Titomanlio, Vito Speranza, Valerio Brucato
    Abstract:

    Abstract Numerical simulation of the injection Moulding Process of thermoplastic polymers has been performed on the basis of the Williams and Lord model and its recent extensions. The aim of the simulation was to identify material properties which play a relevant role to Process modelling, including post filling stages. Predictions improve significantly by taking into account the effect of pressure on both viscosity and crystallisation kinetics. Several features, however, are not satisfactorily predicted. Also the relevance of convection during packing has been evidenced especially with reference to gate sealing time. As highly oriented crystalline structures are present in the final moulded object, the enhancement of crystallisation kinetics by the effect of flow is suggested as the phenomenon to be accounted for in order to gain a quantitative description of the whole Process.