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

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 20 ◽  
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.

scholarly journals A Conceptional Approach of Resin-Transfer-Molding to Rosin-Sourced Epoxy Matrix Green Composites

Aerospace ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Sicong Yu ◽  
Xufeng Zhang ◽  
Xiaoling Liu ◽  
Chris Rudd ◽  
Xiaosu Yi
Keyword(s):  
Composite Laminates ◽  
Resin Transfer Molding ◽  
High Viscosity ◽  
Ramie Fiber ◽  
Liquid Composite Molding ◽  
Curing Agent ◽  
Molding Process ◽  
Transfer Molding ◽  
Low Viscosity ◽  
Composite Molding

In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites.

scholarly journals Comparison of in-plane resin transfer molding and vacuum-assisted resin transfer molding ‘effective’ permeabilities based on mold filling experiments and simulations

2019 ◽  
Vol 39 (1-2) ◽  
pp. 31-44 ◽  
Author(s):  
Mert Hancioglu ◽  
E Murat Sozer ◽  
Suresh G Advani
Keyword(s):  
Effective Permeability ◽  
Thickness Distribution ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Flow Patterns ◽  
Resin Flow ◽  
Liquid Composite Molding ◽  
Molding Process ◽  
Coupled Models ◽  
Transfer Molding

Resin transfer molding and vacuum-assisted resin transfer molding are two of the most commonly used liquid composite molding processes. For resin transfer molding, mold filling simulations can predict the resin flow patterns and location of voids and dry spots which has proven useful in designing the mold and injection locations for composite parts. To simulate vacuum-assisted resin transfer molding, even though coupled models are successful in predicting flow patterns and thickness distribution, the input requires fabric compaction characterization in addition to permeability characterization. Moreover, due to the coupled nature of flow and fabric compaction, the simulation is computationally expensive precluding the possibility to optimize the flow design for reliable production. In this work, we present an alternative approach to characterize and use an “effective” permeability in the resin transfer molding solver to simulate resin flow in vacuum-assisted resin transfer molding. This decoupled method is very efficient and provides reasonable results. The deviations in mold filling times between experiments and simulations for the resin transfer molding process with E-glass CSM and carbon 5HS were 4.7% and 1.0%, respectively, while for the vacuum-assisted resin transfer molding case using “effective permeability value” with E-glass CSM and carbon 5HS fabrics were 11.1% and 12.3%, respectively, which validates the approach presented.

Compression Resin Transfer Molding Using Inflatable Seals

2021 ◽  
Vol 900 ◽  
pp. 3-8
Author(s):  
Ahmed Ouezgan ◽  
Said Adima ◽  
Aziz Maziri ◽  
El Hassan Mallil ◽  
Jamal Echaabi
Keyword(s):  
Resin Transfer Molding ◽  
Mold Cavity ◽  
Liquid Composite Molding ◽  
Transfer Molding ◽  
Resin Injection ◽  
New Variant ◽  
Filling Time ◽  
Composite Molding ◽  
Fiber Reinforcements ◽  
Compression Resin Transfer Molding

Compression resin transfer molding using inflatable seals is a new variant of LCM (“Liquid composite molding”) processes, which uses the inflatable seals to compress the fiber reinforcements and drive the resin to impregnate the fabric preform, resulting to fill the entire mold cavity. During resin injection, the preform is relaxed. Consequently, the resin enters easily and quickly into the mold cavity. After, the necessary resin is injected into the mold cavity, the compression stage takes place, in a stepwise manner, by swelling the inflatable seals. The objective of this paper is to present this new process and study the effect of the number of inflatable seals on the filling time.

scholarly journals COMPUTATIONAL MODELING OF RTM AND LRTM PROCESSES APPLIED TO COMPLEX GEOMETRIES

2012 ◽  
Vol 11 (1-2) ◽  
pp. 93 ◽  
Author(s):  
J. Da S. Porto ◽  
M. Letzow ◽  
E. D. Dos Santos ◽  
S. C. Amico ◽  
J. A. Souza ◽  
...  
Keyword(s):  
Porous Medium ◽  
Flow Behavior ◽  
Resin Transfer Molding ◽  
Three Dimensional ◽  
Complex Geometries ◽  
Resin Flow ◽  
Transfer Molding ◽  
Rtm Process ◽  
General Terms ◽  
Filling Time

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.

Similarity Relations of Resin Flow in Resin Transfer Molding Process

2009 ◽  
Vol 18 (2) ◽  
pp. 135-152 ◽  
Author(s):  
Moon-Kwang Um ◽  
Joon-Hyung Byun ◽  
Isaac M. Daniel
Keyword(s):  
Resin Transfer Molding ◽  
Resin Flow ◽  
Molding Process ◽  
Transfer Molding ◽  
Similarity Relations

Particle distribution from in-plane resin flow in a resin transfer molding process

2018 ◽  
Vol 59 (1) ◽  
pp. 22-34 ◽  
Author(s):  
Bryan M. Louis ◽  
Jesus Maldonado ◽  
Florian Klunker ◽  
Paolo Ermanni
Keyword(s):  
Particle Distribution ◽  
Resin Transfer Molding ◽  
Resin Flow ◽  
Molding Process ◽  
Transfer Molding

Determination of the Thermal Dispersion Coefficient During Radial Filling of a Porous Medium

2003 ◽  
Vol 125 (5) ◽  
pp. 875-880 ◽  
Author(s):  
Mylene Deleglise ◽  
Pavel Simacek ◽  
Christophe Binetruy ◽  
Suresh Advani
Keyword(s):  
Porous Media ◽  
Dispersion Coefficient ◽  
Resin Transfer Molding ◽  
Liquid Composite Molding ◽  
Thermal Dispersion ◽  
Transfer Molding ◽  
Thermoset Resin ◽  
Composite Molding ◽  
Fibrous Porous Media

Resin Transfer Molding is one of the Liquid Composite Molding processes in which a thermoset resin is infiltrated into a fibrous porous media in a closed mold. To reduce the curing time of the resin, the mold may be heated, influencing other filling parameters such as the resin viscosity. Analysis of the non-isothermal effects during filling will help to understand the manufacturing process. One of the issues of non-isothermal filling in porous media is the variation of the velocity profile at the micro scale level, which as it is averaged, cannot be included in the convective term. To account for it, the thermal conductivity tensor is modified and a thermal dispersion coefficient Kd is introduced to model the micro convection effects. In this paper, we explore the temperature profile under non-isothermal conditions for radial injection during Resin Transfer Molding in order to determine the thermal dispersion coefficient. An approximate solution is derived from the series solution and validated with a numerical method. Experiments using carbon fibers and polyester resin were conducted. The thermal dispersion coefficient is determined by comparing experimental results with the steady state analytical solution. The comparison between radial and linear injection results shows that the same degree of dispersion is present in isotropic fibrous porous media.

Effects of Weirs on the Resin Transfer Molding Process

2001 ◽  
Author(s):  
Kiran M. D’Silva ◽  
Su-Seng Pang ◽  
Kurt C. Schulz
Keyword(s):  
Glass Fibers ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Laminated Plates ◽  
Molding Process ◽  
Outlet Port ◽  
Transfer Molding ◽  
Inlet Port ◽  
Rtm Process ◽  
Filling Time

Abstract Low mold filling time and improper fiber wetting are the main problems faced by the manufacturers applying the Resin Transfer Molding (RTM) process. The objective of this work was to minimize these problems and to study the effect of weirs on the RTM process. A mold was designed such that the lower mold plate contains two weirs, one at the resin inlet port and the other at the outlet port. The purpose of adding the weirs is to provide a continuous inlet stream near the resin inlet port and to cause backpressure near the outlet port to induce complete mold filling. Laminated plates were prepared using glass fibers and epoxy resin (combination of EPON resin-862 and curing agent W). The test parameters investigated, such as void contents, dry spots and mold filling time, were compared with those of samples that were prepared without the use of weirs. It was found that the presence of weirs resulted in significant elimination of dry spots, minimization of void contents and a reduction in mold filling time. As a result, the cost required to manufacture composite parts can be reduced by the use of weirs. In addition to the experimental investigation, a computer simulation (using LCMFLOT software) of resin flow inside the mold cavity was conducted. Many simulations were run in order to optimize the height and shape of the weir. Rectangular weirs of height 2.54 mm showed minimum mold fill time. It was found that the results obtained from the experimental work and flow simulations are in good agreement. Based on this work, it is evident that complex parts can be produced in less cycle time if weirs are positioned at appropriate locations.

scholarly journals Mold Filling Simulation of Resin Transfer Molding Combining BEM and Level Set Method

2011 ◽  
Vol 62 ◽  
pp. 57-65 ◽  
Author(s):  
Renaud Gantois ◽  
Arthur Cantarel ◽  
Gilles Dusserre ◽  
Jean Noel Félices ◽  
Fabrice Schmidt
Keyword(s):  
Level Set ◽  
Resin Transfer Molding ◽  
Mold Design ◽  
Liquid Composite Molding ◽  
Two Dimensional ◽  
Dimensional Approach ◽  
Present Contribution ◽  
Transfer Molding ◽  
Composite Molding ◽  
Filling Simulation

Liquid Composite Molding (LCM) is a popular manufacturing process used in many industries. In Resin Transfer Molding (RTM), the liquid resin flows through the fibrous preform placed in a mold. Numerical simulation of the filling stage is a useful tool in mold design. In this paper the implemented method is based on coupling a Boundary Element Method (BEM) with a Level Set tracking. The present contribution is a two-dimensional approach, decoupled from kinetics, thermal analysis and reinforcement deformation occurring during the flow. Applications are presented and tested, including a flow close to industrial conditions.

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