Data assimilation through integration of stochastic resin flow simulation with visual observation during vacuum-assisted resin transfer molding: A numerical study

Light Resin Transfer Molding (LRTM) is a variation of the conventional manufacturing process known as Resin Transfer Molding (RTM). In general terms, these manufacturing processes consist of a closed mould with a preplaced fibrous preform through which a polymeric resin is injected, filling the mold completely, producing parts with complex geometries (in general) and good finish. Those processes differ, among other aspects, in the way that injection occurs. In the RTM process the resin is injected through discrete points whereas in LRTM it is injected into an empty channel (with no porous medium) which surrounds the entire mold perimeter. There are several numerical studies involving the RTM process but LRTM has not been explored enough by the scientific community. Based on that, this work proposes a numerical model developed in the FLUENT package to study the resin flow behavior in the LRTM process. Darcy’s law and Volume of Fluid method (VOF) are used to treat the interaction between air and resin during the flow in the porous medium, i.e. the mold filling problem. Moreover, two three-dimensional geometries were numerically simulated considering the RTM and LRTM processes. It was possible to note the huge differences about resin flow behavior and filling time between these processes to manufacture the same parts.

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Similarity Relations of Resin Flow in Resin Transfer Molding Process

Advanced Composite Materials ◽

10.1163/156855109x428745 ◽

2009 ◽

Vol 18 (2) ◽

pp. 135-152 ◽

Cited By ~ 2

Author(s):

Moon-Kwang Um ◽

Joon-Hyung Byun ◽

Isaac M. Daniel

Keyword(s):

Resin Transfer Molding ◽

Resin Flow ◽

Molding Process ◽

Transfer Molding ◽

Similarity Relations

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A Semi-Analytical Model to Predict Infusion Time and Reinforcement Thickness in VARTM and SCRIMP Processes

Polymers ◽

10.3390/polym11010020 ◽

2018 ◽

Vol 11 (1) ◽

pp. 20 ◽

Cited By ~ 9

Author(s):

Felice Rubino ◽

Pierpaolo Carlone

Keyword(s):

Resin Transfer Molding ◽

Resin Flow ◽

Liquid Composite Molding ◽

Molding Process ◽

Transfer Molding ◽

Deformable Porous Media ◽

Filling Time ◽

Composite Molding ◽

Fabric Deformation ◽

Porosity And Permeability

In liquid composite molding processes, such as resin transfer molding (RTM) and vacuum assisted resin transfer molding (VARTM), the resin is drawn through fiber preforms in a closed mold by an induced pressure gradient. Unlike the RTM, where a rigid mold is employed, in VARTM, a flexible bag is commonly used as the upper-half mold. In this case, fabric deformation can take place during the impregnation process as the resin pressure inside the preform changes, resulting in continuous variations of reinforcement thickness, porosity, and permeability. The proper approach to simulate the resin flow, therefore, requires coupling deformation and pressure field making the process modeling more complex and computationally demanding. The present work proposes an efficient methodology to add the effects of the preform compaction on the resin flow when a deformable porous media is considered. The developed methodology was also applied in the case of Seeman’s Composite Resin Infusion Molding Process (SCRIMP). Numerical outcomes highlighted that preform compaction significantly affects the resin flow and the filling time. In particular, the more compliant the preform, the more time is required to complete the impregnation. On the other hand, in the case of SCRIMP, the results pointed out that the resin flow is mainly ruled by the high permeability network.

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A Numerical Study of Integrated Direct Cure Kinetics Characterization and Control for Resin Transfer Molding (RTM)

Materials ◽

10.1115/imece2005-80669 ◽

2005 ◽

Author(s):

Kuang-Ting Hsiao

Keyword(s):

Control System ◽

Numerical Study ◽

Resin Transfer Molding ◽

Cure Kinetics ◽

Mold Temperature ◽

Fiber Preform ◽

Transfer Molding ◽

Cure Cycle ◽

Numerical Case Study

In Resin Transfer Molding (RTM), the fiber preform is first placed inside a mold cavity and is subsequently impregnated with liquid resin. After mold filling, the resin starts to cure and bind the fiber preform into a solid composite part. The cure cycle will affect the residual stress built during RTM and must be controlled. Traditionally, the cure cycle control is achieved through three steps: offline resin cure kinetics characterization, offline cure cycle optimization, and mold temperature control. Different from other traditional cure cycle control approaches, this paper presents an investigation to achieve an integrated cure kinetics characterization-control system by combining a newly developed direct cure kinetics characterization method with online cure cycle optimization. A methodology to seamlessly combine these components for a practicable online cure characterization-control system will be presented and demonstrated by a numerical case study. The accuracy and reliability of this methodology will be examined and discussed based on the results of the numerical case study.

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