Vacuum-assisted resin transfer molding using tackified fiber preforms

2001 ◽  
Vol 22 (6) ◽  
pp. 721-729 ◽  
Author(s):  
Chih-Hsin Shih ◽  
Qingfang Liu ◽  
L. James Lee
Keyword(s):  
Resin Transfer Molding ◽  
Transfer Molding ◽  
Fiber Preforms

Formation of Microscopic Voids in Resin Transfer Molded Composites

Materials ◽  
2003 ◽  
Author(s):  
Youssef K. Hamidi ◽  
Levent Aktas ◽  
M. Cengiz Altan
Keyword(s):  
Epoxy Composite ◽  
Resin Transfer Molding ◽  
Microscopic Analysis ◽  
Void Content ◽  
Fiber Preform ◽  
Composite Part ◽  
Transfer Molding ◽  
Average Size ◽  
Induced Defects ◽  
Fiber Preforms

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.

Compression and Relaxation Behavior of Dry Fiber Preforms for Resin Transfer Molding

2010 ◽  
Vol 44 (15) ◽  
pp. 1801-1820 ◽  
Author(s):  
Seung Hwan Lee ◽  
Jeong Hwa Han ◽  
Seong Yun Kim ◽  
Jae Ryoun Youn ◽  
Young Seok Song
Keyword(s):  
Resin Transfer Molding ◽  
Relaxation Behavior ◽  
Transfer Molding ◽  
Fiber Preforms

scholarly journals Prediction of Defect Formation during Resin Impregnation Process through a Multi-Layered Fiber Preform in Resin Transfer Molding by a Proposed Analytical Model

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2055 ◽  
Author(s):  
Dong Seong ◽  
Shino Kim ◽  
Doojin Lee ◽  
Jin Yi ◽  
Sang Kim ◽  
...  
Keyword(s):  
Defect Formation ◽  
Resin Transfer Molding ◽  
Compressive Behavior ◽  
Fiber Preform ◽  
Transfer Molding ◽  
Resin Impregnation ◽  
Reinforced Composite ◽  
Fiber Deformation ◽  
Occurrence Type ◽  
Fiber Preforms

It is very important to predict any defects occurring by undesired fiber deformations to improve production yields of resin transfer molding, which has been widely used for mass production of carbon fiber reinforced composite parts. In this study, a simple and efficient analytic scheme was proposed to predict deformations of a multi-layered fiber preform by comparing the forces applied to the preform in a mold of resin transfer molding. Friction coefficient of dry and wet states, permeability, and compressive behavior of unidirectional (UD) and plain woven (PW) carbon fabrics were measured, which were used to predict deformations of the multi-layered fiber preforms with changing their constitution ratios. The model predicted the occurrence, type, and position of fiber deformation, which agreed with the experimental results of the multi-layered preforms.

Formation of Microscopic Voids in Resin Transfer Molded Composites

2004 ◽  
Vol 126 (4) ◽  
pp. 420-426 ◽  
Author(s):  
Youssef K. Hamidi ◽  
Levent Aktas ◽  
M. Cengiz Altan
Keyword(s):  
Epoxy Composite ◽  
Resin Transfer Molding ◽  
Microscopic Analysis ◽  
Void Content ◽  
Fiber Preform ◽  
Composite Part ◽  
Transfer Molding ◽  
Average Size ◽  
Induced Defects ◽  
Fiber Preforms

Performance of composite materials usually suffers from process-induced defects such as dry spots and 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 found to concentrate primarily 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, void content was found to fluctuate through-the-thickness of the composite. Variation up to 17% of the average void 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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