A Model for Unsaturated Flow in Woven Fiber Preforms during Mold Filling in Resin Transfer Molding

Performance of composite materials usually suffers from process-induced defects such as dry spots or microscopic voids. While effects of void content in molded composites have been studied extensively, knowledge of void morphology and spatial distribution of voids in composites manufactured by resin transfer molding (RTM) remains limited. In this study, through-the-thickness void distribution for a disk-shaped, E-glass/epoxy composite part manufactured by resin transfer molding is investigated. Microscopic image analysis is conducted through-the-thickness of a radial sample obtained from the molded composite disk. Voids are primarily found to concentrate within or adjacent to the fiber preforms. More than 93% of the voids are observed within the preform or in a so-called transition zone, next to a fibrous region. In addition, viod content was found to fluctuate through-the-thickness of the composite. Variation up to 17% of the average viod content of 2.15% is observed through-the-thicknesses of the eight layers studied. Microscopic analysis revealed that average size of voids near the mold surfaces is slightly larger than those located at the interior of the composite. In addition, average size of voids that are located within the fiber preform is observed to be smaller than those located in other regions of the composite. Finally, proximity to the surface is found to have no apparent effect on shape of voids within the composite.

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The Effect of Fiber Preform on the Mold Filling Stage of Resin Transfer Molding

Proceedings of the 2016 International Conference on Applied Mathematics, Simulation and Modelling ◽

10.2991/amsm-16.2016.63 ◽

2016 ◽

Author(s):

Changchun Dong ◽

Jianxin Zhou

Keyword(s):

Resin Transfer Molding ◽

Mold Filling ◽

Fiber Preform ◽

Transfer Molding ◽

Filling Stage

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NUMERICAL ANALYSIS OF INFUSION STRATEGIES IN VACUUM ASSISTED RESIN TRANSFER MOLDING (VARTM) PROCESS

International Journal of Modern Manufacturing Technologies ◽

10.54684/ijmmt.2021.13.3.117 ◽

2021 ◽

Vol 13 (3) ◽

pp. 117-124

Author(s):

Himanshu V. Patel ◽

◽

Harshit K. Dave ◽

Keyword(s):

Resin Transfer Molding ◽

Mold Filling ◽

Vital Role ◽

Simulation Approach ◽

Gating System ◽

Composite Manufacturing ◽

Transfer Molding ◽

Filling Stage ◽

Filling Time ◽

Vartm Process

The Liquid composite Molding (LCM) process, such as Vacuum Assisted Resin Transfer Molding (VARTM), offers a fast and high-quality production of composites laminates. In the VARTM process, the simulation tool is found beneficial to predict and solve composite manufacturing issues. The part quality is dependent on the resin mold filling stage in the VARTM process. The infiltration of resin into a porous fibrous medium is taken place during the resin mold filling stage. The permeability has a crucial role during the resin mold filling stage. In this study, simulation of resin infusion through multiple injection gates is discussed. The various infusion schemes are simulated to identify defect-free composite manufacturing. The simulation approach is applied to five different stacking sequences of reinforcements. In this transient simulation study, permeability and resin viscosity is essential inputs for the resin flow. The simulation approach found that a gating scheme plays a vital role in mold filling time and defect-free composite fabrication. It is found that the line gating system can be useful for fast mold filling over the point gating system.

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