Fabrication of T-Shaped Structural Composite through Resin Transfer Molding

1995 ◽  
Vol 29 (16) ◽  
pp. 2192-2214 ◽  
Author(s):  
Wen-Bin Young ◽  
Min-Te Chuang
Keyword(s):  
Low Cost ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Transfer Molding ◽  
Rtm Process ◽  
Resin Impregnation ◽  
Composite Fabrication ◽  
Fiber Reinforcements ◽  
Fiber Materials ◽  
Dry Spot

Resin transfer molding (RTM) combines resin impregnation and composite fabrication in one process. It simplifies the process for composite fabrication and has the advantages of automation, low cost, and versatile design of fiber reinforcements. The RTM process was used in this study to fabricate T-shaped stuctural composites. Edge effects due to the gap between the fiber mats and the mold or the imperfect sealing of the matting mold resulted in edge channeling flows, leading to dry spot enclosure in the composite. It was found that a vacuum in the mold cavity could reduce the size of the dry spot. Proper control or prevention of the edge flows will reduce the possibility of dry spot formation. Numerical simulations of the mold filling were conducted to study the effect of gate locations on the mold filling patterns and edge channeling flows. Mechanical pulling tests were conducted to investigate the joint strengths of the T-shaped structure for different fiber materials. Fiber stitching on the rib provided an improvement in the joint strength while different fiber materials without fiber stitching tended to have the same joint strengths.

Study on Compression Transfer Molding

1995 ◽  
Vol 29 (16) ◽  
pp. 2180-2191 ◽  
Author(s):  
Wen-Bin Young ◽  
Cheng-Wey Chiu
Keyword(s):  
Low Cost ◽  
Fiber Reinforcement ◽  
Mold Filling ◽  
Thickness Direction ◽  
Molding Process ◽  
Transfer Molding ◽  
Rtm Process ◽  
Resin Impregnation ◽  
Filling Time ◽  
Part Dimension

Resin transfer molding (RTM) finishes the resin impregnation and composite fabrication at the same time. It simplifies the process for composites fabrication and has the advantages of automation, low cost, and versatile design of fiber reinforcement. Therefore, the RTM process is widely used in the architecture, automotive, and aerospace industries. However, in the RTM process, resin must flow through the fiber reinforcement in the planar direction, which, in some cases such as fabrications of large panels, may need a long time for the mold filling. If the part dimension is too large or the fiber permeability is too low, the mold filling process may not be able to complete before the resin gels. Therefore, some modification for the RTM process is necessary in order to reduce the mold filling time. In the compression transfer molding, the mold opens a small gap for the resin to fill in between fiber mats and the mold, and then compresses the fiber reinforcement to be impregnated by the resin in the thickness direction. In this way, since resin is forced into the fiber reinforcements in the thickness direction, the damage of the fibers will be minimized. In addition, the mold filling time will be reduced due to the different flow path of the resin inside the mold. This study explored the possibility of using the compression transfer molding process and also identified the key parameters regarding the process.

Using Computer Simulation as a Process Design Tool for Resin Injection Pultrusion (RIP)

2000 ◽  
Author(s):  
Zhongman Ding ◽  
Shoujie Li ◽  
L. James Lee ◽  
Herbert Engelen
Keyword(s):  
Modeling And Simulation ◽  
Process Design ◽  
Resin Transfer Molding ◽  
Transfer Molding ◽  
Pultrusion Process ◽  
Rtm Process ◽  
Resin Impregnation ◽  
Heating Section ◽  
Resin Injection ◽  
Resin Injection Pultrusion

Abstract Resin Injection Pultrusion (RIP) is a new composite manufacturing process, which combines the advantages of the conventional pultrusion process and the Resin Transfer Molding (RTM) process. It is sometimes referred to the Continuous Resin Transfer Molding (C-RTM) process. The RIP process differs from the conventional pultrusion process in that the resin is injected into an injection-die (instead of being placed in an open bath) in order to eliminate the emission of volatile organic compounds (styrene) (VOC) during processing. Based on the modeling and simulation of resin/fiber “pultrudability”, resin flow, and heat transfer and curing, a computer aided engineering tool has been developed for the purpose of process design. In this study, the fiber stack permeability and compressibility are measured and modeled, and the resin impregnation pattern and pressure distribution inside the fiber stack are obtained using numerical simulation. Conversion profiles in die heating section of the pultrusion die can also be obtained using the simulation tool. The correlation between the degree-of-cure profiles and the occurrence of blisters in the pultruded composite parts is discussed. Pulling force modeling and analysis are carried out to identify the effect on composite quality due to interface friction between the die surface and the moving resin/fiber mixture. Experimental data are used to verify the modeling and simulation results.

Sliding Wear and Friction Properties of Stitched RTM Base Carbon–Carbon Composites

2005 ◽  
Author(s):  
M. K. Surappa ◽  
Kunigal N. Shivakumar
Keyword(s):  
Sliding Wear ◽  
Resin Transfer Molding ◽  
Carbon Composites ◽  
Wear Rates ◽  
Transfer Molding ◽  
Rtm Process ◽  
Composite Fabrication ◽  
Wear And Friction ◽  
Pin On Disc ◽  
Set Up

This paper presents wear and friction properties of carbon-carbon composites (CCC) manufactured by resin transfer molding (RTM) process. During composite fabrication thickness stitching was employed to improve inter laminar tension and shear properties. Wear and Friction characteristics of carbon-carbon composites were evaluated using pin-on-disc set up. Results of test indicate that surface of composites having stitches in a perpendicular direction show increase in wear rates with increase in load.

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.

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.

scholarly journals Some Issues about the Numerical simulation of Mold Filling in Resin Transfer Molding

1992 ◽  
Vol 1 (1) ◽  
pp. 096369359200100 ◽  
Author(s):  
F Trochu ◽  
R Gauvin
Keyword(s):  
Numerical Simulation ◽  
Porous Medium ◽  
Finite Elements ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Time Step ◽  
Transfer Molding ◽  
Darcy Equation ◽  
Resin Impregnation ◽  
Flow Through

The resin impregnation of the fibrous reinforcement in resin transfer molding (RTM) is usually modeled as a flow through a porous medium (Darcy's law). In our model, Darcy equation is solved numerically at each time step using non-conforming finite elements on a fixed grid.

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.

Neural Network Based Control of Preform Permeation in Resin Transfer Molding Processes With Real-Time Permeability Estimation

2000 ◽  
Author(s):  
David Nielsen ◽  
Ranga Pitchumani
Keyword(s):  
Neural Network ◽  
Real Time ◽  
Resin Transfer Molding ◽  
Local Pressure ◽  
Transfer Molding ◽  
Model Based ◽  
Rtm Process ◽  
Virtual Sensing ◽  
Intelligent Model ◽  
Injection Pressures

Abstract Variabilities in the preform structure in situ in the mold are an acknowledged challenge to effective permeation control in the Resin Transfer Molding (RTM) process. An intelligent model-based controller is developed which utilizes real-time virtual sensing of the permeability to derive optimal decisions on controlling the injection pressures at the mold inlet ports so as to track a desired flowfront progression during resin permeation. This model-based optimal controller employs a neural network-based predictor that models the flowfront progression, and a simulated annealing-based optimizer that optimizes the injection pressures used during actual control. Preform permeability is virtually sensed in real-time, based on the flowfront velocities and local pressure gradient estimations along the flowfront. Results are presented which illustrate the ability of the controller in accurately steering the flowfront for various fill scenarios and preform geometries.

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.

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