Study on the monitoring of resin flow and curing in the vacuum assisted resin transfer molding process using a long-period fiber bragg grating

This article examines the use of fiber Bragg grating sensors for cure monitoring purposes in resin transfer molding processes. Within a resin transfer molding test series a thermoset epoxy-amine resin system was used in combination with a woven flax fiber reinforcement. Particular attention was paid on the location of the optical fiber sensor and its sensitive Bragg grating element inside the mold cavity. Three different installation approaches were tested and the correlation of the corresponding strain response with the actual cure state of the resin system was investigated at 50°C and 70°C isothermal cure temperature, respectively. We could demonstrate that characteristic, conspicuous strain changes are directly related to the sol–gel conversion of the thermoset polymer, which was analyzed considering different approaches for the gel-point detection based on rheological measurements. With the installation of the sensor inside a controllable, capsuled resin volume, we could achieve the most reliable strain response that provides capabilities to give in-situ information of the cure state beyond the gelation point.

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Vibration monitoring for aircraft wing model using fiber Bragg grating array packaged by vacuum-assisted resin transfer molding

Optical Engineering ◽

10.1117/1.oe.56.9.094102 ◽

2017 ◽

Vol 56 (09) ◽

pp. 1 ◽

Cited By ~ 2

Author(s):

Wen Zhang ◽

Xiaolong Liu ◽

Wei He ◽

Mingli Dong ◽

Lianqing Zhu

Keyword(s):

Fiber Bragg Grating ◽

Resin Transfer Molding ◽

Vibration Monitoring ◽

Bragg Grating ◽

Aircraft Wing ◽

Transfer Molding ◽

Wing Model ◽

Grating Array

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Similarity Relations of Resin Flow in Resin Transfer Molding Process

Advanced Composite Materials ◽

10.1163/156855109x428745 ◽

2009 ◽

Vol 18 (2) ◽

pp. 135-152 ◽

Cited By ~ 2

Author(s):

Moon-Kwang Um ◽

Joon-Hyung Byun ◽

Isaac M. Daniel

Keyword(s):

Resin Transfer Molding ◽

Resin Flow ◽

Molding Process ◽

Transfer Molding ◽

Similarity Relations

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A Semi-Analytical Model to Predict Infusion Time and Reinforcement Thickness in VARTM and SCRIMP Processes

Polymers ◽

10.3390/polym11010020 ◽

2018 ◽

Vol 11 (1) ◽

pp. 20 ◽

Cited By ~ 9

Author(s):

Felice Rubino ◽

Pierpaolo Carlone

Keyword(s):

Resin Transfer Molding ◽

Resin Flow ◽

Liquid Composite Molding ◽

Molding Process ◽

Transfer Molding ◽

Deformable Porous Media ◽

Filling Time ◽

Composite Molding ◽

Fabric Deformation ◽

Porosity And Permeability

In liquid composite molding processes, such as resin transfer molding (RTM) and vacuum assisted resin transfer molding (VARTM), the resin is drawn through fiber preforms in a closed mold by an induced pressure gradient. Unlike the RTM, where a rigid mold is employed, in VARTM, a flexible bag is commonly used as the upper-half mold. In this case, fabric deformation can take place during the impregnation process as the resin pressure inside the preform changes, resulting in continuous variations of reinforcement thickness, porosity, and permeability. The proper approach to simulate the resin flow, therefore, requires coupling deformation and pressure field making the process modeling more complex and computationally demanding. The present work proposes an efficient methodology to add the effects of the preform compaction on the resin flow when a deformable porous media is considered. The developed methodology was also applied in the case of Seeman’s Composite Resin Infusion Molding Process (SCRIMP). Numerical outcomes highlighted that preform compaction significantly affects the resin flow and the filling time. In particular, the more compliant the preform, the more time is required to complete the impregnation. On the other hand, in the case of SCRIMP, the results pointed out that the resin flow is mainly ruled by the high permeability network.

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Particle distribution from in-plane resin flow in a resin transfer molding process

Polymer Engineering & Science ◽

10.1002/pen.24860 ◽

2018 ◽

Vol 59 (1) ◽

pp. 22-34 ◽

Cited By ~ 1

Author(s):

Bryan M. Louis ◽

Jesus Maldonado ◽

Florian Klunker ◽

Paolo Ermanni

Keyword(s):

Particle Distribution ◽

Resin Transfer Molding ◽

Resin Flow ◽

Molding Process ◽

Transfer Molding

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Comparison of in-plane resin transfer molding and vacuum-assisted resin transfer molding ‘effective’ permeabilities based on mold filling experiments and simulations

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684419868015 ◽

2019 ◽

Vol 39 (1-2) ◽

pp. 31-44 ◽

Cited By ~ 2

Author(s):

Mert Hancioglu ◽

E Murat Sozer ◽

Suresh G Advani

Keyword(s):

Effective Permeability ◽

Thickness Distribution ◽

Resin Transfer Molding ◽

Mold Filling ◽

Flow Patterns ◽

Resin Flow ◽

Liquid Composite Molding ◽

Molding Process ◽

Coupled Models ◽

Transfer Molding

Resin transfer molding and vacuum-assisted resin transfer molding are two of the most commonly used liquid composite molding processes. For resin transfer molding, mold filling simulations can predict the resin flow patterns and location of voids and dry spots which has proven useful in designing the mold and injection locations for composite parts. To simulate vacuum-assisted resin transfer molding, even though coupled models are successful in predicting flow patterns and thickness distribution, the input requires fabric compaction characterization in addition to permeability characterization. Moreover, due to the coupled nature of flow and fabric compaction, the simulation is computationally expensive precluding the possibility to optimize the flow design for reliable production. In this work, we present an alternative approach to characterize and use an “effective” permeability in the resin transfer molding solver to simulate resin flow in vacuum-assisted resin transfer molding. This decoupled method is very efficient and provides reasonable results. The deviations in mold filling times between experiments and simulations for the resin transfer molding process with E-glass CSM and carbon 5HS were 4.7% and 1.0%, respectively, while for the vacuum-assisted resin transfer molding case using “effective permeability value” with E-glass CSM and carbon 5HS fabrics were 11.1% and 12.3%, respectively, which validates the approach presented.

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Use of Sensors and Actuators to Address Flow Disturbances During the Resin Transfer Molding Process

10.1115/imece2001/htd-24357 ◽

2001 ◽

Author(s):

Jeffrey M. Lawrence ◽

Suresh G. Advani

Keyword(s):

Resin Transfer Molding ◽

Input Parameter ◽

Resin Flow ◽

Sensors And Actuators ◽

Molding Process ◽

Flow Paths ◽

Arrival Times ◽

Transfer Molding ◽

Flow Disturbances ◽

Molded Parts

Abstract In Resin Transfer Molding a fiber preform is placed in a mold, the mold is closed and a thermoset polymeric resin is injected through gates into the mold to saturate the preform completely. The resin flow rate is controlled by actuators, which are usually injection machines. When one places the preform into the mold, the gap between the preform and the mold walls can create racetracking channels and provide the resin flow paths that can severely influence the flow patterns and drastically change the flow history. As this gap is unavoidable and not reproducible, one could have different strengths of this disturbance from one part to the next, some of which will cause incomplete saturation of the fibers by the resin. Hence, an active control of the filling stage is necessary which can detect and characterize the race tracking and provide the control action to re-direct the flow with the aim to saturate the preform without resin starved regions (macro voids or dry spots). A methodology is proposed that intelligently places sensors in the mold to detect the resin arrival times at these locations. This information is used to determine and quantify the strength of the disturbance and used as an input parameter for the actuators to redirect the flow. This paper demonstrates this methodology on a simple mold configuration, and outlines how this technique can be generalized to any mold geometry or disturbance set in an automated RTM environment. Numerical simulations are used to establish the control methodologies, and all of the efforts are confirmed in a laboratory setting. The proposed methodology should prove useful in increasing the yield of Resin Transfer Molded parts.

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