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.

Flow Characteristics of Vacuum Assisted Resin Transfer Molding Process Depending on the Capillary Phenomenon

2013 ◽  
Vol 762 ◽  
pp. 612-620 ◽  
Author(s):  
Yun Hae Kim ◽  
Jin Woo Lee ◽  
Jun Mu Park
Keyword(s):  
Low Cost ◽  
Resin Transfer Molding ◽  
Flow Characteristics ◽  
Molding Process ◽  
Transfer Molding ◽  
Filling Stage ◽  
Resin Impregnation ◽  
Movement Mechanism ◽  
Capillary Phenomenon ◽  
Vartm Process

Reducing the cost of composite material production is significant for expanding its usage and application in many ways, such as in the fields of aerospace, aviation, ocean industry and so on. To do this, It is important to minimize the production process of the material and to decrease the amount of scraps or any unnecessary particles. The Vacuum Assisted Resin Transfer Molding (VARTM) process, which is known for having many advantages, has become recognized as one of the most low-cost manufacturing model. VARTM process can be divided into three main steps: performing, resin filling and hardening steps. The most important step among all these three steps is the Resin Filling stage, a process when resin is impregnated into the mat. Mostly, Resin Filling stage is greatly affected by the level of permeability, a characteristic of stiffener due to pneumatic resistant nature in the process. Other factors such as viscosity, technological vacuuming, or even stiffening process itself could also influence the production as well. During Resin Filling stage, Resin tends to spread out in the center first because of capillary phenomenon. In this research, the researchers examined the mechanical property and the pneumatic nature of Resin by dividing the pneumatic movement of the Resin into sections. Based on this result, the researchers found the correlations between the capillary phenomenon and Resin impregnation, and analyzed the movement mechanism in Resin filling stage.

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]

AN EXPERIMENTAL STUDY OF MICRO-VOID CREATION BY IMPURITY IN COMPOSITE MATERIALS DURING VARTM PROCESS

2011 ◽  
Vol 25 (31) ◽  
pp. 4204-4207 ◽  
Author(s):  
Yun-Hae Kim ◽  
Kyung-Man Moon ◽  
Byeong-Woo Lee ◽  
Joon-Young Kim ◽  
Dong-Hun Yang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Composite Materials ◽  
Environmental Control ◽  
Resin Transfer Molding ◽  
Transfer Molding ◽  
Large Structures ◽  
Vartm Process

The effects of impurities on the generation of voids in composites fabricated by vacuum-assisted resin transfer molding was investigated to help reduce mechanical weakening in large structures. Impurities were intentionally inserted into laminates, which were then observed optically. Internal voids were generated in specimens with impurities of 2 – 3mm thickness. The voids grew as the impurities' thicknesses increased to 4 – 5 mm. The voids' diameters were proportional to the thickness of the impurity. Void generation was shown to depend on the thickness of impurities. Environmental control during vacuum-assisted resin transfer molding was shown to be important for ensuring the quality of the resulting composites.

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

Use of Resin Transfer Molding Simulation to Predict Flow, Saturation, and Compaction in the VARTM Process

2004 ◽  
Vol 126 (2) ◽  
pp. 210-215 ◽  
Author(s):  
N. C. Correia ◽  
F. Robitaille ◽  
A. C. Long ◽  
C. D. Rudd ◽  
P. Sˇima´cˇek ◽  
...  
Keyword(s):  
Resin Transfer Molding ◽  
Flow Simulation ◽  
Continuity Condition ◽  
Simulation Software ◽  
Molding Process ◽  
Numerical Work ◽  
Transfer Molding ◽  
Outlet Pressure ◽  
Analytical Work ◽  
Vartm Process

The present paper examines the analysis and simulation of the vacuum assisted resin transfer molding process (VARTM). VARTM differs from the conventional resin transfer molding (RTM) in that the thickness of the preform varies during injection affecting permeability and fill time. First, a governing equation for VARTM is analytically developed from the fundamental continuity condition, and used to show the relation between parameters in VARTM. This analytical work is followed by the development of a numerical 1-D/2-D solution, based on the flow simulation software LIMS, which can be used to predict flow and time dependent thickness of the preform by introducing models for compaction and permeability. Finally, the results of a VARTM experimental plan, focusing on the study of the influence of outlet pressure on compaction and fill time, are correlated with both the analytical and the numerical work. The present work also proposes an explanation for the similarities between VARTM and RTM and shows when modeling VARTM and RTM can result in an oversimplification.

Use of Resin Transfer Molding Simulation to Predict Flow, Saturation and Compaction in the VARTM Process

2002 ◽  
Author(s):  
N. C. Correia ◽  
F. Robitaille ◽  
A. C. Long ◽  
C. D. Rudd ◽  
P. Sˇima´cˇek ◽  
...  
Keyword(s):  
Resin Transfer Molding ◽  
Molding Process ◽  
Transfer Molding ◽  
Injection Process ◽  
Software Packages ◽  
Compaction Force ◽  
Thickness Variations ◽  
Filling Simulation ◽  
Complex Parts ◽  
Vartm Process

Vacuum Assisted Resin Transfer Molding (VARTM) and Resin Transfer Molding (RTM) are among the most significant and widely used Liquid Composite manufacturing processes. In RTM preformed-reinforcement materials are placed in a mold cavity, which is subsequently closed and infused with resin. RTM numerical simulations have been developed and used for a number of years for gate assessment and optimization purposes. Available simulation packages are capable of describing/predicting flow patterns and fill times in geometrically complex parts manufactured by the resin transfer molding process. Unlike RTM, the VARTM process uses only one sided molds (tool surfaces) where performs are placed and enclosed by a sealed vacuum bag. To improve the delivery of the resin, a distribution media is sometimes used to cover the preform during the injection process. Attempts to extend the usability of the existing RTM algorithms and software packages to the VARTM domain have been made but there are some fundamental differences between the two processes. Most significant of these are 1) the thickness variations in VARTM due to changes in compaction force during resin flow 2) fiber tow saturation, which may be significant in the VARTM process. This paper presents examples on how existing RTM filling simulation codes can be adapted and used to predict flow, thickness of the preform during the filling stage and permeability changes during the VARTM filling process. The results are compared with results obtained from an analytic model as well as with limited experimental results. The similarities and differences between the modeling of RTM and VARTM process are highlighted.

Manufacturing method of carbon and glass fabric composites with dispersed nanofibers using vacuum-assisted resin transfer molding

e-Polymers ◽  
2014 ◽  
Vol 14 (5) ◽  
pp. 345-352 ◽  
Author(s):  
Jun Hee Song
Keyword(s):  
Carbon Nanofiber ◽  
Fiber Composite ◽  
Structural Characteristics ◽  
Glass Fibers ◽  
Resin Transfer Molding ◽  
Processing Parameters ◽  
Resin Matrix ◽  
Carbon Fiber Composite ◽  
Manufacturing Method ◽  
Transfer Molding

AbstractFiber-reinforced composites have favorable structural characteristics such as their light weight, high specific strength, and high stiffness. Vacuum-assisted resin transfer molding (VARTM), used for manufacturing these composites, is relatively simple and provides materials with excellent mechanical properties. In this study, the author investigated the utility of VARTM in improving the performance of a carbon nanofiber (CNF)/carbon fiber composite impregnated with thermosetting resin. Processing parameters were determined, and the integrity of the manufactured composites was assessed. Carbon and glass fibers were used as reinforcing materials in an epoxy resin matrix. CNFs, which have excellent thermal and electrical characteristics, were dispersed in the composites. The pore sizes using the 0°/90°- and 90°/45° types of laminates were about 45 and 50 μm, respectively. The integrated composites produced had low porosity (below 3.7×10-5%).

Application of Calcium Carbonate in Resin Transfer Molding Process

2014 ◽  
Vol 353 ◽  
pp. 39-43 ◽  
Author(s):  
Iran Rodrigues de Oliveira ◽  
Sandro Campos Amico ◽  
R. Barcella ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Calcium Carbonate ◽  
Low Cost ◽  
Resin Transfer Molding ◽  
Injection Pressure ◽  
Molding Process ◽  
Transfer Molding ◽  
Industrial Sectors ◽  
Advanced Composite Materials ◽  
Filling Time ◽  
Manufacturing Techniques

Resin Transfer Molding (RTM) is one of the most widely known composite manufacturing techniques of the liquid molding family, being extensively studied and used to obtain advanced composite materials comprised of fibers embedded in a thermoset polymer matrix. Nowadays, RTM is used by many industrial sectors such as automotive, aerospace, civil and sporting equipment. Therefore, the objective of this study is to verify the effect of calcium carbonate mixed in resin in the RTM process. Several rectilinear infiltration experiments were conducted using glass fiber mat molded in a RTM system with cavity dimensions of 320 x 150 x 3.6 mm, room temperature, maximum injection pressure 0.202 bar and different content of CaCO3 (10 and 40%) with particle size of 75μm. The results show that the use of filled resin with CaCO3 influences the preform impregnation during the RTM molding, changing the filling time and flow from position, however it is possible to make the composite with a good quality and low cost.

Effect of CaCO3 Content in Resin Transfer Molding Process

2013 ◽  
Vol 334-335 ◽  
pp. 188-192 ◽  
Author(s):  
Iran Rodrigues de Oliveira ◽  
Sandro Campos Amico ◽  
F. Ferreira Luz ◽  
R. Barcella ◽  
V.M. França Bezerra ◽  
...  
Keyword(s):  
Porous Media ◽  
Low Cost ◽  
Resin Transfer Molding ◽  
Molding Process ◽  
Transfer Molding ◽  
Advanced Composite ◽  
Rtm Process ◽  
Advanced Composite Materials ◽  
Closed Mold ◽  
The Individual

Composite material can be defined as a combination of two or more materials on a macroscale to form a useful material, often showing properties that none of the individual independent components shows. Resin Transfer Molding (RTM) is one of the most widely known composite manufacturing technique of the liquid molding family, being extensively studied and used to obtain advanced composite materials comprised of fibers embedded in a thermoset polymer matrix. This technique consists in injecting a resin pre-catalysed thermosetting in a closed mold containing a dry fiber preform, where the resin is impregnated. The aim of this study is to investigate the effect caused by the use of CaCO3filled resin on the characteristics of the RTM process. Several experiments were conducted using glass fiber mat and polyester resin molded in a RTM system with cavity dimensions of 320 x 150 x 3.6 mm, at room temperature, and different CaCO3content (0, 10, 20, 30 and 40% in weight). The results show that the use of filled resin with CaCO3influences the resin viscosity and the porous media permeability, making it difficult to fill the porous media during the molding process, however it is possible to make composite with a good quality and low cost.

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