Evaluation of fiber content in GFRP bars using digital image processing

Morales, Carlos; Claure, Guillermo; Álvarez, Jorge; Nanni, Antonio

doi:10.1016/j.compositesb.2020.108307

Cited by 17 publications

(7 citation statements)

References 4 publications

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“…The CSM layer is made of randomly arranged fibers embedded with the same resin. The density, the Young's Modulus and the Poisson ratio of the fiber and matrix are 2.57 g/cm 3 , 72.0 GPa and 0.21; and 1.12 g/cm 3 , 3.5 GPa and 0.3, respectively.…”

Section: Methodsmentioning

confidence: 97%

“…The homogenization of the increasing ROI sizes was made to achieve the convergence of the ROI effective elastic properties to the effective elastic properties of an RVE. The chosen sizes of ROI were 100 3 , 200 3 , 300 3 , 400 3 and 500 3 voxels.…”

Section: Roving Layermentioning

confidence: 99%

“…Studies [2][3][4] on the physical characterization of fiber reinforced polymers (FRP) through image analysis usually focus on the content and distribution of material phases (fiber, resin and voids). However, most studies employ traditional image processing strategies, which are based on the grey level intensity of voxels.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Pultruded Glass-Fiber Reinforced Polymers with Two-Step Homogenization

et al. 2023

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The aim of this work is to determine effective elastic properties of pultruded Glass Fiber Reinforced Polymer using micro-CT in conjunction with a two-step numerical homogenization technique. The two-step homogenization involves the segmentation of the material's layers, which was made here by means of a machine learning approach. The segmentation was validated through the comparison between the phase's volume fractions of samples obtained from the segmented images and laboratory tests. Further, a standard accuracy analysis in a 10-fold cross validation was performed. The samples' effective axial Young's modulus obtained by our numerical homogenization were compared to results obtained from experimental tests. For both the experimental tests and the image-based numerical analysis we considered samples extracted from the same profile. The two-step methodology allowed the homogenization of large volumes of the composite corresponding to the whole thickness of the profile, imaged with a high resolution. In addition to the axial effective Young's modulus, our methodology was also able to successfully provide all the other elastic properties along the three orthogonal directions, even the ones that are arduous to be obtained in laboratory setups.

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Section: Methodsmentioning

confidence: 97%

Section: Roving Layermentioning

confidence: 99%

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Characterization of Pultruded Glass-Fiber Reinforced Polymers with Two-Step Homogenization

et al. 2023

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“…Another study 14 used digital image processing (DIP) scanning electron microscopy (SEM) images to perform micrograph analysis, which was then used to calculate fiber volume fractions, and comparable volume fraction values were obtained with the burn-off resin technique.…”

Section: Introductionmentioning

confidence: 99%

Investigation of fiber content evaluation methods of carbon fiber reinforced thermoplastic composites

Asfew

Moens

Ivens

2023

Journal of Thermoplastic Composite Materials

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Thermoplastic-based composites are becoming the preferred material for structural and non-structural components in the composite production industries. One of the most critical elements determining the characteristics and performance of fiber-reinforced composites is the fiber content. The fiber volume fraction (Vf) of carbon/polyamide410 (C-PA410) composite is evaluated using standard acid digestion, the unique two-stage thermogravimetry (TGA) method and 2D image processing method, with Vf values of 24.0%, 23.1%, and 18.3%, respectively. For statistical purposes, a substantial number of samples from each composite batch were tested and analyzed. The two-stage TGA approach used in this study, involves measuring the constituent content of carbon fiber thermoplastic composites in nitrogen first and subsequently in air. The standard acid digestion and the two-stage TGA method used in this study provided comparable results. The 2D image processing method, on the other hand, yields a lower volume fraction of fiber. The two-stage TGA approach has been proven to be more convenient in terms of accuracy, safety, and speed. This technique has been validated by testing a control specimen of a material (Toray Cetex® TC910 PA6) with a known weight fraction.

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“…The V f values from different locations within I-shaped pultruded profiles were observed via optical microscopy and image processing in [30], and the fiber distribution was reported as neither uniform nor totally random. Local and global variability of fiber volume fraction in pultruded profiles differs for the reinforcement type or geometry of the profile [31,32]. In the resin bath pultrusion, the resin impregnated rovings are consolidated by a solid die and the excess resin is bleed out via squeeze flow [33].…”

Section: Introductionmentioning

confidence: 99%

Mesoscale Process Modeling of a Thick Pultruded Composite with Variability in Fiber Volume Fraction

et al. 2021

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Pultruded fiber-reinforced polymer composites are susceptible to microstructural nonuniformity such as variability in fiber volume fraction (Vf), which can have a profound effect on process-induced residual stress. Until now, this effect of non-uniform Vf distribution has been hardly addressed in the process models. In the present study, we characterized the Vf distribution and accompanying nonuniformity in a unidirectional fiber-reinforced pultruded profile using optical light microscopy. The identified nonuniformity in Vf was subsequently implemented in a mesoscale thermal–chemical–mechanical process model, developed explicitly for the pultrusion process. In our process model, the constitutive material behavior was defined locally with respect to the corresponding fiber volume fraction value in different-sized representative volume elements. The effect of nonuniformity on the temperature and cure degree evolution, and residual stress was analyzed in depth. The results show that the nonuniformity in fiber volume fraction across the cross-section increased the absolute magnitude of the predicted residual stress, leading to a more scattered residual stress distribution. The observed Vf gradient promotes tensile residual stress at the core and compressive residual stress at the outer regions. Consequently, it is concluded that it is essential to take the effects of nonuniformity in fiber distribution into account for residual stress estimations, and the proposed numerical framework was found to be an efficient tool to study this aspect.

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Evaluation of fiber content in GFRP bars using digital image processing

Cited by 17 publications

References 4 publications

Characterization of Pultruded Glass-Fiber Reinforced Polymers with Two-Step Homogenization

Characterization of Pultruded Glass-Fiber Reinforced Polymers with Two-Step Homogenization

Investigation of fiber content evaluation methods of carbon fiber reinforced thermoplastic composites

Mesoscale Process Modeling of a Thick Pultruded Composite with Variability in Fiber Volume Fraction

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