Fiber optic sensors for use in monitoring flow front in vacuum resin transfer molding processes

1997 ◽  
Vol 68 (5) ◽  
pp. 2156-2157 ◽  
Author(s):  
J. R. Bernstein ◽  
J. W. Wagner
Keyword(s):  
Fiber Optic ◽  
Resin Transfer Molding ◽  
Fiber Optic Sensors ◽  
Flow Front ◽  
Transfer Molding

A Closed Form Solution for Flow During the Vacuum Assisted Resin Transfer Molding Process

1999 ◽  
Vol 122 (3) ◽  
pp. 463-475 ◽  
Author(s):  
K-T. Hsiao ◽  
R. Mathur ◽  
S. G. Advani ◽  
J. W. Gillespie, ◽  
B. K. Fink
Keyword(s):  
Closed Form ◽  
Scaling Laws ◽  
Resin Transfer Molding ◽  
Closed Form Solution ◽  
Form Solution ◽  
Flow Front ◽  
Molding Process ◽  
Transfer Molding ◽  
Front Region ◽  
Insight Into

A closed form solution to the flow of resin in vacuum assisted resin transfer molding process (VARTM) has been derived. VARTM is used extensively for affordable manufacturing of large composite structures. During the VARTM process, a highly permeable distribution medium is incorporated into the preform as a surface layer. During infusion, the resin flows preferentially across the surface and simultaneously through the preform giving rise to a complex flow front. The analytical solution presented here provides insight into the scaling laws governing fill times and resin inlet placement as a function of the properties of the preform, distribution media and resin. The formulation assumes that the flow is fully developed and is divided into two regimes: a saturated region with no crossflow and a flow front region where the resin is infiltrating into the preform from the distribution medium. The flow front region moves with a uniform velocity. The law of conservation of mass and Darcy’s Law for flow through porous media are applied in each region. The resulting equations are nondimensionalized and are solved to yield the flow front shape and the development of the saturated region. It is found that the flow front is parabolic in shape and the length of the saturated region is proportional to the square root of the time elapsed. The results thus obtained are compared to data from full scale simulations and an error analysis of the solution was carried out. It was found that the time to fill is determined with a high degree of accuracy while the error in estimating the flow front length, d, increases with a dimensionless parameter ε=K2xxh22/K2yyd2. The solution allows greater insight into the process physics, enables parametric and optimization studies and can reduce the computational cost of full-scale 3-dimensional simulations. A parametric study is conducted to establish the sensitivity of flow front velocity to the distribution media/preform thickness ratio and permeabilities and preform porosity. The results provide insight into the scaling laws for manufacturing of large scale structures by VARTM. [S1087-1357(00)02002-5]

Characterization of Flow Front in Resin Transfer Molding

1997 ◽  
Author(s):  
Devdas Pai ◽  
Samuel Owusu-Ofori ◽  
Robert Sadler
Keyword(s):  
Resin Transfer Molding ◽  
Flow Front ◽  
Transfer Molding

Flow front measurements and model validation in the vacuum assisted resin transfer molding process

2001 ◽  
Vol 22 (4) ◽  
pp. 477-490 ◽  
Author(s):  
R. Mathuw ◽  
S. G. Advani ◽  
D. Heider ◽  
C. Hoffmann ◽  
J. W. Gillespie ◽  
...  
Keyword(s):  
Model Validation ◽  
Resin Transfer Molding ◽  
Flow Front ◽  
Molding Process ◽  
Transfer Molding

A Study on Resin Flow through a Multi-layered Preform in Resin Transfer Molding

2002 ◽  
Vol 10 (7) ◽  
pp. 493-510 ◽  
Author(s):  
D. G. Seong ◽  
K Chung ◽  
T. J. Kang ◽  
J. R. Youn
Keyword(s):  
Resin Transfer Molding ◽  
Mold Filling ◽  
Transverse Flow ◽  
Woven Fabrics ◽  
Weighted Averaging ◽  
Resin Flow ◽  
Flow Front ◽  
Transfer Molding ◽  
Filling Time ◽  
Flow Through

In resin transfer molding, mold filling is governed by the flow of resin through a preform which is considered as an anisotropic porous media. The resin flow is usually described by Darcy's law and the permeability tensor must be obtained for filling analysis. When the preform is composed of more than two layers with different in-plane permeability, effective average permeability should be determined for the flow analysis in the mold. The most frequently used averaging scheme is the weighted averaging scheme, but it does not account for the transverse flow between adjacent layers. A new averaging scheme is suggested to predict the effective average permeability of the multi-layered preform, which accounts for the transverse flow effect. When the flow in the mold is unsaturated, the effective average permeability is predicted by using the predicted mold filling time and transverse permeability. The new scheme is verified by measuring the effective permeability of the multi-layered preforms which consist of glass fiber random mats, carbon fiber woven fabrics, aramid fiber woven fabrics. Fluid flow through the preform composed of more than two layers with different in-plane permeability shows different flow fronts between layers. The difference in the flow front advancement is observed with a digital camcorder. The predicted flow front is compared with the experimental results and shows a good agreement. It is expected that the effective average permeability can be used for modeling the resin flow through the multi-layered preform.

scholarly journals Numerical Analysis of the Resin Transfer Molding Process via PAM-RTM Software

2015 ◽  
Vol 365 ◽  
pp. 88-93 ◽  
Author(s):  
I.R. Oliveira ◽  
Sandro Campos Amico ◽  
J.A. Souza ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Room Temperature ◽  
Polyester Resin ◽  
Resin Transfer Molding ◽  
Injection Pressure ◽  
Flow Front ◽  
Molding Process ◽  
Transfer Molding ◽  
Front Profile ◽  
Flat Flow ◽  
Half Length

This work aims to investigate the infiltration of a CaCO3filled resin in fibrous porous media (resin transfer molding process) using the PAM-RTM software. A preform of glass fiber mat (fraction 30%), with dimensions 320 x 150 x 3.6 mm, has been used in rectilinear injection experiments conducted at room temperature and injection pressure 0.25, 0.50 and 0.75 bar. The polyester resin contain 0% and 40% CaCO3. The numerical results were evaluated by direct comparison with experimental data. The flat flow-front profile of the rectilinear flow was reached approximately half length of the mold. It was observed, that the both velocity infiltration and permeability have decreased with increasing the CaCO3content, thus, increasing the time to processing of the composite material.

The Thickness and the Inerior Quality of Composite Panel in the Vacuum Assisted Resin Transfer Molding Process

2011 ◽  
Vol 686 ◽  
pp. 468-473
Author(s):  
Yan Liang Li ◽  
Xiao Su Yi ◽  
Bang Ming Tang
Keyword(s):  
Fiber Composite ◽  
Low Cost ◽  
Resin Transfer Molding ◽  
Composite Panel ◽  
Flow Front ◽  
Carbon Fiber Composite ◽  
Molding Process ◽  
Transfer Molding ◽  
Vartm Process

The objective of this paper was focused on predicting the thickness and the interior quality of carbon fiber composite panel during the vacuum assisted resin transfer molding (VARTM) process. The character of the VARTM process determined that it was low cost. A panel made of Epoxy resin, and carbon fibers, was used as the simplest article to experiment and except routine items, the thickness and the interior quality was focused. In the process, the flow front of the resin was record using a digital camera. Darcy’s law was the model of resin flow. The results showed that the flow front history would reach unanimous, thickness near the edges was difficult to control, and most of the porosity came from the injection line where more resin cumulated.

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