Investigation of the 2D assumption in the image-based inertial impact test
Investigation of the 2D assumption in the image-based inertial impact test
The image-based inertial impact (IBII) test has shown promise for measuring properties of composites at strain rates where existing test methods become unreliable due to inertial effects (> 10
2 s
−1). Typically, the IBII tests are performed with a single camera, and therefore, to use surface measurements for material property identification, it is necessary to assume that the test is two-dimensional. In this work, synchronised ultra-high-speed cameras are used to quantify the relevance of this assumption when nonuniform, through-the-thickness loading is applied to interlaminar samples. Initial experiments revealed that an angular misalignment of approximately 1° between the impact faces of the waveguide and projectile created a bending wave that propagated along the sample behind the axial pulse. Even under these conditions, consistent measurements of stiffness were made by assuming a linear distribution of the behaviour through-the-thickness. When the misalignment was reduced to 0.2°, the effects on single-sided measurements were significantly reduced. The two alignment cases were compared to show that three-dimensional loading had a small effect on stiffness identification (approximately 5% bias) relative to failure stress (approximately 30% bias). This study highlights the importance of impact alignment for reliable characterisation of the interlaminar failure stress and was used to establish guidelines for diagnosing loading issues from single-sided measurements.
fibre-reinforced polymer composites, high strain rate, image-based inertial impact (IBII) test, interlaminar properties, ultra-high-speed imaging
Van Blitterswyk, Jared
d113eca6-6ee0-4f0e-a983-b5636fadbd71
Fletcher, Lloyd
48dca64b-f93c-4655-9205-eaf4e74be90c
Pierron, Fabrice
a1fb4a70-6f34-4625-bc23-fcb6996b79b4
February 2021
Van Blitterswyk, Jared
d113eca6-6ee0-4f0e-a983-b5636fadbd71
Fletcher, Lloyd
48dca64b-f93c-4655-9205-eaf4e74be90c
Pierron, Fabrice
a1fb4a70-6f34-4625-bc23-fcb6996b79b4
Van Blitterswyk, Jared, Fletcher, Lloyd and Pierron, Fabrice
(2021)
Investigation of the 2D assumption in the image-based inertial impact test.
Strain, 57 (1), [e12369].
(doi:10.1111/str.12369).
Abstract
The image-based inertial impact (IBII) test has shown promise for measuring properties of composites at strain rates where existing test methods become unreliable due to inertial effects (> 10
2 s
−1). Typically, the IBII tests are performed with a single camera, and therefore, to use surface measurements for material property identification, it is necessary to assume that the test is two-dimensional. In this work, synchronised ultra-high-speed cameras are used to quantify the relevance of this assumption when nonuniform, through-the-thickness loading is applied to interlaminar samples. Initial experiments revealed that an angular misalignment of approximately 1° between the impact faces of the waveguide and projectile created a bending wave that propagated along the sample behind the axial pulse. Even under these conditions, consistent measurements of stiffness were made by assuming a linear distribution of the behaviour through-the-thickness. When the misalignment was reduced to 0.2°, the effects on single-sided measurements were significantly reduced. The two alignment cases were compared to show that three-dimensional loading had a small effect on stiffness identification (approximately 5% bias) relative to failure stress (approximately 30% bias). This study highlights the importance of impact alignment for reliable characterisation of the interlaminar failure stress and was used to establish guidelines for diagnosing loading issues from single-sided measurements.
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Accepted/In Press date: 31 August 2020
e-pub ahead of print date: 6 October 2020
Published date: February 2021
Additional Information:
Funding Information:
This material is based on research sponsored by the Air Force Research Laboratory, under Agreement Number FA9550‐17‐1‐0133. The authors are grateful to the grant programme manager, Dr. David Garner from EOARD/AFOSR. The U.S. Government is authorised to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Air Force Research Laboratory or the U.S. Government. The authors kindly acknowledge Dr. Devlin Hayduke from Material Sciences Corporation, USA, for supplying the material tested in this work. The authors would like to thank Sam Parry and Xavier Régal for their technical assistance in performing the experiments. Dr. Lloyd Fletcher and Prof. Fabrice Pierron acknowledge support from EPSRC through Grant EP/L026910/1. Jared Van Blitterswyk acknowledges the PhD funding support from EPSRC.
Funding Information:
This material is based on research sponsored by the Air Force Research Laboratory, under Agreement Number FA9550-17-1-0133. The authors are grateful to the grant programme manager, Dr. David Garner from EOARD/AFOSR. The U.S. Government is authorised to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Air Force Research Laboratory or the U.S. Government. The authors kindly acknowledge Dr. Devlin Hayduke from Material Sciences Corporation, USA, for supplying the material tested in this work. The authors would like to thank Sam Parry and Xavier R?gal for their technical assistance in performing the experiments. Dr. Lloyd Fletcher and Prof. Fabrice Pierron acknowledge support from EPSRC through Grant EP/L026910/1. Jared Van Blitterswyk acknowledges the PhD funding support from EPSRC.
Publisher Copyright:
© 2020 The Authors. Strain published by John Wiley & Sons Ltd
Keywords:
fibre-reinforced polymer composites, high strain rate, image-based inertial impact (IBII) test, interlaminar properties, ultra-high-speed imaging
Identifiers
Local EPrints ID: 443795
URI: http://eprints.soton.ac.uk/id/eprint/443795
ISSN: 1475-1305
PURE UUID: b774fcad-574b-4129-ab11-048b65a00202
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Date deposited: 11 Sep 2020 16:41
Last modified: 17 Mar 2024 05:52
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Author:
Jared Van Blitterswyk
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