Applying Magnetic Consolidation Pressure During Cure to Improve Laminate Quality: A Comparative Analysis of Wet Lay-Up and Vacuum Assisted Resin Transfer Molding Processes

2017 ◽  
Author(s):  
Maya Pishvar ◽  
Mehrad Amirkhosravi ◽  
M. Cengiz Altan
Keyword(s):  
Composite Laminates ◽  
Permanent Magnets ◽  
Volume Fraction ◽  
Resin Transfer Molding ◽  
Void Content ◽  
Fiber Volume ◽  
Transfer Molding ◽  
Consolidation Pressure ◽  
A New Technique

This paper presents the application of a new technique, Magnet Assisted Composite Manufacturing (MACM), to enhance the quality of composite laminates fabricated by wet lay-up/vacuum bag (WLVB) and vacuum assisted resin transfer molding (VARTM). Towards this goal, a set of high-power, Neodymium permanent magnets, which are placed on a magnetic tool plate, is applied on the vacuum bag/lay-up. To further demonstrate the effectiveness of MACM, six-ply random mat, E-glass/epoxy composite laminates are produced under four processing scenarios: (i) Conventional WLVB; (ii) WLVB with magnetic consolidation; (iii) Conventional VARTM; and (iv) VARTM with magnetic consolidation. Applying magnetic consolidation pressure is found to be a convenient and efficient method for enhancing the overall quality of the laminates fabricated by WLVB and VARTM. For instance, in WLVB-MACM process, fiber volume fraction improves by 98% to 49% and void content reduces from 5% to less than 1.5% compared to conventional WLVB. These two factors lead to substantially increased mechanical properties of the WLVB-MACM laminates to a level comparable to those achieved by the higher-cost VARTM-MACM process.

VARTM Process Improvement for Repeatable and Improved Mechanical Properties of Composite Laminates

2009 ◽  
Author(s):  
Sanjay Sharma ◽  
Dennis A. Siginer
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Composite Laminates ◽  
Volume Fraction ◽  
Void Content ◽  
Molding Process ◽  
Fiber Volume ◽  
The Impact ◽  
Vartm Process

Quality of laminates produced by Seeman Composite Resin Infusion Molding Process (SCRIMP) is studied by comparing their Fiber Volume fraction and void content. SCRIMP is a variant of Vacuum Assisted Resin Transfer Molding (VARTM). Manufacturing process parameters are then identified and varied to study the impact on mechanical properties of laminated composites. Modification to SCRIMP is carried out by infusing the resin under additional pressure. Optimal process parameters for this modified SCRIMP process are suggested to yield laminates that are repeatable and consistent in quality. Void content is reduced in the composite laminates by altering the vacuum pressure level. Thickness gradient commonly found in SCRIMP processed laminates is eliminated by allowing longer de-bulking time. Final laminate quality is measured using ASTM standardized mechanical testing.

Pressurized Infusion: A New and Improved Liquid Composite Molding Process

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
M. Akif Yalcinkaya ◽  
Gorkem E. Guloglu ◽  
Maya Pishvar ◽  
Mehrad Amirkhosravi ◽  
E. Murat Sozer ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Composite Laminates ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Compaction Pressure ◽  
External Pressure ◽  
Void Content ◽  
Liquid Composite Molding ◽  
Molding Process ◽  
Fiber Volume

Vacuum-assisted resin transfer molding (VARTM) has several inherent shortcomings such as long mold filling times, low fiber volume fraction, and high void content in fabricated laminates. These problems in VARTM mainly arise from the limited compaction of the laminate and low resin pressure. Pressurized infusion (PI) molding introduced in this paper overcomes these disadvantages by (i) applying high compaction pressure on the laminate by an external pressure chamber placed on the mold and (ii) increasing the resin pressure by pressurizing the inlet resin reservoir. The effectiveness of PI molding was verified by fabricating composite laminates at various levels of chamber and inlet pressures and investigating the effect of these parameters on the fill time, fiber volume fraction, and void content. Furthermore, spatial distribution of voids was characterized by employing a unique method, which uses a flatbed scanner to capture the high-resolution planar scan of the fabricated laminates. The results revealed that PI molding reduced fill time by 45%, increased fiber volume fraction by 16%, reduced void content by 98%, improved short beam shear (SBS) strength by 14%, and yielded uniform spatial distribution of voids compared to those obtained by conventional VARTM.

scholarly journals Impact and shear properties of carbon fabric/ poly-dicyclopentadiene composites manufactured by vacuum‐assisted resin transfer molding

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 437-443 ◽  
Author(s):  
Hyeong Min Yoo ◽  
Moo Sun Kim ◽  
Bum Soo Kim ◽  
Dong Jun Kwon ◽  
Sung Woong Choi
Keyword(s):  
Impact Strength ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Resin Transfer Molding ◽  
Maximum Shear Stress ◽  
Weight Percent ◽  
Fiber Volume ◽  
Shear Properties ◽  
Transfer Molding ◽  
The Impact

AbstractDicyclopentadiene (DCPD) resin has gained popularity owing to its fast curing time and ease of processing with a low viscosity in the monomer state. In the present study, the impact and shear properties of a carbon fiber (CF)/p-DCPD composite were investigated. The CF/p-DCPD composite was manufactured by vacuum-assisted resin transfer molding with CF as the reinforcement and p-DCPD as the resin with a maximum fiber volume fraction of 55 weight percent. Impact and shear properties of the CF/p-DCPD composite were evaluated and compared with those of a CF/Epoxy composite. The maximum shear stress and modulus of the CF/p-DCPD composite were lower than that of the CF/Epoxy composite. However, the CF/p-DCPD composite had higher toughness than that of the CF/Epoxy composite; this indicates that it is tougher and exhibits a more ductile load-displacement response with a lower modulus and larger failure deformation. The impact strength of the CF/p-DCPD composite was about three time that of the CF/Epoxy composite. The higher impact strength of the CF/p-DCPD composite is attributed to the resin characteristics: epoxy resin has a more brittle behavior, and hence, higher energy is required for crack propagation due to fracture.

The effect of different variables on in-plane radial permeability of natural fiber mats

2016 ◽  
Vol 37 (19) ◽  
pp. 1191-1201 ◽  
Author(s):  
Michael Ehresmann ◽  
Ali Amiri ◽  
Chad Ulven
Keyword(s):  
Fiber Volume Fraction ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Resin Transfer Molding ◽  
Limited Information ◽  
Fiber Volume ◽  
Fiber Mats ◽  
Transfer Molding ◽  
Fiber Size ◽  
Wax Content

There has been a vast growth in manufacturing of fiber reinforced plastics by means of liquid composite molding such as resin transfer molding and vacuum-assisted resin transfer molding processes. In these processes, compression of the porous media and pressure of the injected resin result in in-mold forces that need to be determined. Limited information exists regarding the processing parameters and extent of reinforcing potential natural fibers have in polymer matrices. Current study investigates the effect of different variables such as fiber volume fraction, shive content, fiber size, wax content, and resin viscosity on permeability of five different natural fiber mats. Flax fiber with low-, medium-, and high-shive content as well as hemp and kenaf fiber mats was selected for this study and an original experimental device was setup to measure the permeability of the mentioned fiber mats based on different variables. It was found that increasing fiber volume fraction will result in reduction of permeability of all mats. The presence of shive and larger fiber size increased the permeability. Higher wax content lowered the permeability. These competing factors could be used by manufacturers to produce a mat which had optimum permeability while still maintaining acceptable strength.

The Hand Making of Radius Fillers and the Establishment of its Evaluative Requirements

2014 ◽  
Vol 936 ◽  
pp. 1973-1984
Author(s):  
Hai Lei Wang ◽  
Mei Rong Xiong ◽  
Yue Xin Duan ◽  
Jin Yang ◽  
Dong Xiu Yan ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Nondestructive Testing ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Void Content ◽  
Filling Material ◽  
Fiber Volume ◽  
Composite Girder ◽  
Microstructure And Mechanical Property

Radius filler is a kind of filling material which is used in triangle gap of the composite girder and rib. To optimize the hand-made craft of radius fillers and specify the evaluative requirements for detecting radius fillers, a research on handcraft parameters of the radius fillers had been conducted; the boundary dimension, microstructure and mechanical property of the R6 radius fillers had been characterized with the use of different detective methods and the microanalysis includes: nondestructive testing; microscope photos; fiber volume fraction and void content. The evaluative requirements to detect the quality of radius fillers have been established and its validity has been confirmed by the R8 radius fillers.

Permeability analysis of non-crimp fabrics for resin transfer molding

2019 ◽  
Vol 27 (7) ◽  
pp. 429-439
Author(s):  
Zheng Min Huang ◽  
So Yun Lee ◽  
Hyung Min Kim ◽  
Jae Ryoun Youn ◽  
Young Seok Song
Keyword(s):  
Volume Fraction ◽  
Resin Transfer Molding ◽  
Flow Simulation ◽  
Unit Cell ◽  
Creeping Flow ◽  
Permeability Tensor ◽  
Fiber Volume ◽  
Transfer Molding ◽  
Fiber Reinforced Polymer Composites ◽  
Simulation And Experiment

Resin transfer molding (RTM) is one of the most common processes for producing fiber-reinforced polymer composites. Permeability tensor of the fiber preform is a key material property for satisfactory RTM process. Therefore, it is necessary to acquire a precise permeability tensor from simulation and experiment. In this study, the creeping flow simulation was carried out to obtain the flow field in a unit cell, and Darcy’s law was utilized to compute the permeability tensor. The unit cell for the non-crimp fabrics was defined and constructed, and the permeability was analyzed in the axial, transverse, and thickness directions. The effect of shifted preform layers was also evaluated for more realistic permeability tensor. The predicted and measured results were compared with respect to the fiber volume fraction, fabric pattern, and stacking structure.

Relaxation-Compression Resin Transfer Molding under Magnetic Field

2020 ◽  
Vol 847 ◽  
pp. 81-86
Author(s):  
Ahmed Ouezgan ◽  
Said Adima ◽  
Aziz Maziri ◽  
El Hassan Mallil ◽  
Jamal Echaabi
Keyword(s):  
Magnetic Field ◽  
Volume Fraction ◽  
Resin Transfer Molding ◽  
Molding Process ◽  
Fiber Volume ◽  
Transfer Molding ◽  
Resin Impregnation ◽  
New Variant ◽  
New Process ◽  
Compression Resin Transfer Molding

Relaxation-compression resin transfer molding under magnetic field is a new variant of VARTM (“vacuum assisted resin transfer molding”) process, which uses a flexible magnetic membrane controlled by a magnetic force, in order to govern the relaxation and compression phases by changing the permeability of the fabric preform. Thus permits to the resin to enter easily into the mold and to increase the resin impregnation velocity and the fiber volume fraction. This innovation is based on the application of the TRIZ theory (“the theory of inventive problem solving”), which allows us to answer to the shortcomings and the conflict links exist inside the VARTM processes. The objective of this paper is to present this new process and to study the effect of the current intensity and the separated gap between the flexible magnetic membrane and solenoid on the permeability of the preform.

scholarly journals A Conceptional Approach of Resin-Transfer-Molding to Rosin-Sourced Epoxy Matrix Green Composites

Aerospace ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Sicong Yu ◽  
Xufeng Zhang ◽  
Xiaoling Liu ◽  
Chris Rudd ◽  
Xiaosu Yi
Keyword(s):  
Composite Laminates ◽  
Resin Transfer Molding ◽  
High Viscosity ◽  
Ramie Fiber ◽  
Liquid Composite Molding ◽  
Curing Agent ◽  
Molding Process ◽  
Transfer Molding ◽  
Low Viscosity ◽  
Composite Molding

In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites.

Micro-computed tomography analysis of natural fiber and bio-matrix tubular-braided composites

2019 ◽  
Vol 53 (28-30) ◽  
pp. 4003-4013 ◽  
Author(s):  
Brianna M Bruni-Bossio ◽  
Garrett W Melenka ◽  
Cagri Ayranci ◽  
Jason P Carey
Keyword(s):  
Computed Tomography ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Void Content ◽  
Micro Computed Tomography ◽  
Braided Composites ◽  
Fiber Volume ◽  
Increasing Demand ◽  
Materials Used ◽  
Curing Method

There is an increasing demand for the use of “green”-based materials as reinforcement and matrix materials in composites. However, the ability of these natural-based materials to perform as consistently and reliably as conventional materials is still relatively unknown. A key importance in the viability of these materials is the evaluation of the content of voids and imperfections, which may affect the properties of the entire composite. In this study, the microstructure of tubular-braided composites manufactured from cellulose fibers and a partially bio-derived resin was studied with the use of micro-computed tomography. These methods were used to determine the effect of modifying braid angle, resin type, and curing method on fiber volume fraction, void volume, and void distribution. It was determined that the void content increased with the increase in braid angle, and vacuum-bagging reduced the total void content. The sample with the smallest braid angle produced with vacuum-bagged curing contained a void fraction of 1.5%. The results of this study proved that the materials used could be viable for further testing and development and that micro-computed tomography imaging is valuable for identifying how to improve consistency and minimize imperfections to create more accurate and reliable natural fiber-braided composites.

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