Modeling and Experimental Validation of the VARTM Process for Thin-Walled Preforms

Wu, Da; Larsson, Ragnar; Rouhi, Mohammad Sadegh

doi:10.3390/polym11122003

Cited by 5 publications

(7 citation statements)

References 51 publications

(64 reference statements)

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“…29 Photogrammetry methods have proven to be useful for full field measurement of part thickness in VI. These non-contact methods are based on either the use of multiple cameras as in the case of speckle stereophotogrammetry 13,[30][31][32][33][34][35][36] or the use of a projector and a camera in Structured Light Scanning (SLS). 37 Despite allowing the measurement of full field thickness distribution, the photogrammetry approaches require more advanced algorithms to derive the thickness distribution from the recorded images.…”

Section: Introductionmentioning

confidence: 99%

Monitoring and modeling of part thickness evolution in vacuum infusion process

Caglar

Hancioglu

Sozer

2020

Journal of Composite Materials

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The main hurdles in Vacuum Infusion (VI) are the difficulty in achieving complete mold filling and uniform part thickness. This study integrates process monitoring by full field thickness measurements and resin flow modeling that accounts for compaction and permeability characterizations of fabric reinforcements to assess the evolution of part thickness during filling and post-filling stages of VI process. A Structured Light Scanning system is used for full field thickness monitoring in experiments and a Control Volume Finite Element Method solver is implemented to couple resin flow with fabric’s compaction and permeability. Two cases are studied both experimentally and numerically. Evolutions of thickness and pressure validate the developed flow solver, its accuracy in terms of predicting fill times and fill patterns, suitability and limitations of the elastic compaction models for thickness modeling.

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Section: Introductionmentioning

confidence: 99%

Monitoring and modeling of part thickness evolution in vacuum infusion process

Caglar

Hancioglu

Sozer

2020

Journal of Composite Materials

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“…Moreover, Wu & Larsson [8] suggested a shell model that is capable of simulating both the resin flow and the lubrication and relaxation mechanisms of the preform during the VARTM process. These models have reported good agreements with the initial experiments, e.g., [9]. However, the models, as mentioned above, are limited to the isothermal condition.…”

Section: Introductionmentioning

confidence: 55%

“…From [8] and [9], we obtain a constitutive relation between the fluid pressure and the fiber preform stretch,…”

Section: Fiber Preform Compaction Modelmentioning

confidence: 99%

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A preform deformation and resin flow coupled model including the cure kinetics and chemo-rheology for the VARTM process

Larsson

Blinzler

2020

Int J Mater Form

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The present paper deals with preform deformation and resin flow coupled to cure kinetics and chemo-rheology for the VARTM process. By monitoring the coupled resin infusion and curing steps through temperature control, our primary aim is to reduce the cycle time of the process. The analysis is based on the two-phase porous media flow and the preform deformation extended with cure kinetics and heat transfer. A novel feature is the consideration of temperature and preform deformation coupled to resin viscosity and permeability in the VARTM process. To tackle this problem, we extend the porous media framework with the heat transfer and chemical reaction, involving additional convection terms to describe the proper interactions with the resin flow. Shell kinematics is applied to thin-walled preforms, which significantly reduces the problem size. The proposed finite element discretized system of coupled models is solved in a staggered way to handle the partially saturated flow front under non-isothermal conditions efficiently. From the numerical example, we conclude that the cycle time of the VARTM infusion process can be shortened over 68% with the proper temperature control. Moreover, the proposed framework can be applied to optimize the processing parameters and check the compatibility of a resin system for a given infusion task.

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“…Afterward, the laminate is healed, and both injection and cure can occur at either ambient or elevated temperature. In this process, it is possible to use any fibers, and the stitched materials work well since the gaps allow for the rapid transport of resin [ 36 ]. This is a flawless process using low-cost composite materials without prepregs and autoclaves compared with the conventional composite fabrication process used in the aeronautical field.…”

Section: Vartm Processmentioning

confidence: 99%

Review and Suggestion of Failure Theories in Voids Scenario for VARTM Processed Composite Materials

2021

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Fiber-reinforced composite structures are used in different applications due to their excellent strength to weight ratio. Due to cost and tool handling issues in conventional manufacturing processes, like resin transfer molding (RTM) and autoclave, vacuum-assisted resin transfer molding (VARTM) is the best choice among industries. VARTM is highly productive and cheap. However, the VARTM process produces complex, lightweight, and bulky structures, suitable for mass and cost-effective production, but the presence of voids and fiber misalignment in the final processed composite influences its strength. Voids are the primary defects, and they cannot be eliminated completely, so a design without considering void defects will entail unreliability. Many conventional failure theories were used for composite design but did not consider the effect of voids defects, thus creating misleading failure characteristics. Due to voids, stress and strain uncertainty affects failure mechanisms, such as microcrack, delamination, and fracture. That’s why a proper selection and understanding of failure theories is necessary. This review discusses previous conventional failure theories followed by work considering the void’s effect. Based on the review, a few prominent theories were suggested to estimate composite strength in the void scenario because they consider the effect of the voids through crack density, crack, or void modeling. These suggested theories were based on damage mechanics (discrete damage mechanics), fracture mechanics (virtual crack closure technique), and micromechanics (representative volume element). The suggested theories are well-established in finite element modeling (FEM), representing an effective time and money-saving tool in design strategy, with better early estimation to enhance current design practices' effectiveness for composites. This paper gives an insight into choosing the failure theories for composites in the presence of voids, which are present in higher percentages in mass production and less-costly processes (VARTM).

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Modeling and Experimental Validation of the VARTM Process for Thin-Walled Preforms

Cited by 5 publications

References 51 publications

Monitoring and modeling of part thickness evolution in vacuum infusion process

Monitoring and modeling of part thickness evolution in vacuum infusion process

A preform deformation and resin flow coupled model including the cure kinetics and chemo-rheology for the VARTM process

Review and Suggestion of Failure Theories in Voids Scenario for VARTM Processed Composite Materials

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