Nondestructive characterization of fiber orientation in short fiber reinforced polymer composites with X-ray vector radiography

Prade, Friedrich; Schaff, Florian; Senck, Sascha; Meyer, Pascal; Mohr, J.; Kastner, Johann; Pfeiffer, Franz

doi:10.1016/j.ndteint.2016.11.013

Cited by 70 publications

(36 citation statements)

References 28 publications

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“…Because of a good compromise between resolution and analyzed volume, X‐Ray computed tomography (CT) has been widely used in the characterization of the microstructure of thermoplastics. Different characterizations of flowing WLs using CT are reported that is, in References . A frontal WL was scanned with microfocus X‐ray CT by Nagura et al A quantitative analysis at four different 364 × 364 × 364 μm 3 zones showed that fibers at the WL orient in the transversal‐to‐flow direction and in the thickness direction.…”

Section: Introductionmentioning

confidence: 99%

Frontal weld lines in injection‐molded short fiber‐reinforced PBT: Extensive microstructure characterization for mechanical performance evaluation

et al. 2019

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Different factors contribute to the weakness of weld lines (WLs) induced by injection molding such as unsuitable fiber orientation (FO), incomplete polymer matrix diffusion, voids and V‐notches. This study aims to characterize the contribution of each factor on the weakness of frontal WLs in a short glass fiber‐reinforced polybutylene‐terephthalate characterized by extensive X‐ray computed tomography and mechanical tensile testing assisted with digital image correlation. A reduction of 50% of the stress at break and almost 40% of the strain at break is observed despite the complete matrix healing at the WL interface and the absence of V‐notches. Frontal WLs induce a FO gradient starting 2 to 3 mm before the WL plane. The fibers in the WL region mainly orient in transverse‐to‐flow and thickness direction. This FO gradient localizes the deformations, which leads to failure at a strength near to the one of the unreinforced variant. Voids formation in frontal WLs seems to be driven by large gradients of FO and subsequent anisotropic shrinkage. In addition, this shrinkage behavior at the WL causes an increase of thickness. By applying higher packing pressures, the fibers orient more in flow direction at the core of the WL, leading to a higher tensile strength and a lower content of voids. Finally, we can conclude that the FO is the dominant factor controlling the mechanical performance in frontal WLs.

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Section: Introductionmentioning

confidence: 99%

Frontal weld lines in injection‐molded short fiber‐reinforced PBT: Extensive microstructure characterization for mechanical performance evaluation

et al. 2019

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“…By extracting the parameters A α , Φ α and I α information about the main fibre orientation α = Φ α , the average scattering strength I α , the anisotropic part of the scattering strength A α and the degree of anisotropy V α = A α /I α is obtainable [16,20].…”

Section: Directional X-ray Dark-field Imagingmentioning

confidence: 99%

“…As a further analysis tool, directional X-ray dark-field imaging is used in order to reconstruct fibre orientations of micrometer-sized aligned structures which are not resolvable directly [12][13][14]. The method is applicable for the analysis of bones [15][16][17] or the characterisation of fibre alignments in polymers [18][19][20]. An extension of directional dark-field imaging to a 3D analysis of fibre orientations is done by tensor tomography [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Non-Destructive Testing of Archaeological Findings by Grating-Based X-Ray Phase-Contrast and Dark-Field Imaging

et al. 2018

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Abstract:The analysis of archaeological findings reveals the remaining secrets of human history. However, it is a challenging task to investigate and simultaneously preserve the unique remains. Available non-destructive examination methods are limited and often insufficient. Thus, we considered X-ray grating interferometry as a non-destructive and advanced X-ray imaging method to retrieve more information about archaeological findings. In addition to the conventional attenuation image, the differential phase and the dark-field image are obtained. We studied the potential of the scattering-sensitive dark-field and the phase-shift sensitive differential phase image to analyse archaeological findings. Hereby, the focus lies on organic remnants. Usually, the organic materials have vanished due to decomposition processes, but the structures are often preserved by mineralisation and penetration of corrosion products. We proved that the combination of the attenuation and the dark-field image in particular, enables a separation of structural properties for fabric remnants. Furthermore, we achieved promising results for the reconstruction of sub-pixel sized fibre orientations of woven fabric remnants by employing the directional dark-field imaging method. We conclude from our results that a further application of X-ray dark-field imaging on wet organic findings and on the distinction of different types of organic remnants at archaeological findings is promising.

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“…This has been accomplished by using a technique known as X-ray Vector Radiography (XVR). [20][21][22][23][24] XVR is a technique that calculates the twodimensional orientation of the micro-structure within a sample by using several dark-field images obtained by a phase stepping procedure at different angular poses of the sample (typically placed on an Euler cradle) around the beam propagation direction. It has been shown useful for analyzing the micro-structure of composite materials 21,24 and biological specimen.…”

mentioning

confidence: 99%

“…[20][21][22][23][24] XVR is a technique that calculates the twodimensional orientation of the micro-structure within a sample by using several dark-field images obtained by a phase stepping procedure at different angular poses of the sample (typically placed on an Euler cradle) around the beam propagation direction. It has been shown useful for analyzing the micro-structure of composite materials 21,24 and biological specimen. 20,22,23 The XVR method discussed above requires a timeconsuming stepwise process involving rotation of the sample to several poses and a phase-stepping procedure for every pose.…”

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confidence: 99%

Trochoidal X-ray Vector Radiography: Directional dark-field without grating stepping

Sharma

Bachche

Kageyama

et al. 2018

Applied Physics Letters

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X-ray Vector Radiography (XVR) is an imaging technique that reveals the orientations of sub-pixel sized structures within a sample. Several dark-field radiographs are acquired by rotating the sample around the beam propagation direction and stepping one of the gratings to several positions for every pose of the sample in an X-ray grating interferometry setup. In this letter, we present a method of performing XVR of a continuously moving sample without the need of any grating motion. We reconstruct the orientations within a sample by analyzing the change in the background moire fringes caused by the sample moving and simultaneously rotating in plane (trochoidal trajectory) across the detector field-of-view. Avoiding the motion of gratings provides significant advantages in terms of stability and repeatability, while the continuous motion of the sample makes this kind of system adaptable for industrial applications such as the scanning of samples on a conveyor belt. Being the first step in the direction of utilizing advanced sample trajectories to replace grating motion, this work also lays the foundations for a full three dimensional reconstruction of scattering function without grating motion.

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Nondestructive characterization of fiber orientation in short fiber reinforced polymer composites with X-ray vector radiography

Cited by 70 publications

References 28 publications

Frontal weld lines in injection‐molded short fiber‐reinforced PBT: Extensive microstructure characterization for mechanical performance evaluation

Frontal weld lines in injection‐molded short fiber‐reinforced PBT: Extensive microstructure characterization for mechanical performance evaluation

Non-Destructive Testing of Archaeological Findings by Grating-Based X-Ray Phase-Contrast and Dark-Field Imaging

Trochoidal X-ray Vector Radiography: Directional dark-field without grating stepping

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