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Reducing the notch sensitivity of quasi-isotropic layups using thin-ply hybrid laminates: 30th Annual Technical Conference of the American Society for Composites, ASC 2015

Reducing the notch sensitivity of quasi-isotropic layups using thin-ply hybrid laminates: 30th Annual Technical Conference of the American Society for Composites, ASC 2015
Reducing the notch sensitivity of quasi-isotropic layups using thin-ply hybrid laminates: 30th Annual Technical Conference of the American Society for Composites, ASC 2015
The concept of stress concentration suppression using thin-ply pseudo-ductile hybrid composites is presented in this paper. In previous works, it has been shown that it is possible to achieve high amounts of pseudo-ductility in Uni-Directional (UD) and multi-directional laminates. In this work, the requirements for thin-ply hybrid sublaminates to suppress/reduce notch sensitivity in quasi-isotropic laminates with an open hole is studied. A User Material subroutine (UMAT) has been developed in ABAQUS which can replicate the typical response of pseudo-ductile thin-ply hybrids. This UMAT was then used to study several idealised responses and find the important parameters controlling the fibre failure in notched specimens. The stress concentration factor in the 0° layer has been selected as a measure of notch sensitivity. The ratio of pseudo-ductile strain to initiation strain has also been found to be a useful parameter in comparing different fibre direction tensile responses. The stress concentration factors of the 0° layer found from two different tensile response shapes of UD sub-laminates were found to be very similar when they were plotted versus the ratio of pseudo-ductile strain over initiation strain. These results show that the stress concentration factor varies between 3 for linear elastic material response to 1 for sub-laminates with pseudo-ductile strain to initiation strain ratio of 3. This suggests that optimal structural response can be achieved with thin ply hybrids if the failure strain of the low strain material to high strain material is about 25%.
stress concentration, structural optimization
DEStech Publications Inc.
Jalalvand, M.
21ef0df8-fc7c-4466-a2fc-ee98ed3408a2
Czél, G.
f6a95d06-75a3-4ca8-8912-098395a6eb80
Wisnom, M. R.
655f9d97-0d4c-4654-9b0e-3e5150991e42
Xiao, X.
Liu, D.
Loos, A.
Jalalvand, M.
21ef0df8-fc7c-4466-a2fc-ee98ed3408a2
Czél, G.
f6a95d06-75a3-4ca8-8912-098395a6eb80
Wisnom, M. R.
655f9d97-0d4c-4654-9b0e-3e5150991e42
Xiao, X.
Liu, D.
Loos, A.

Jalalvand, M., Czél, G. and Wisnom, M. R. (2015) Reducing the notch sensitivity of quasi-isotropic layups using thin-ply hybrid laminates: 30th Annual Technical Conference of the American Society for Composites, ASC 2015. In, Xiao, X., Liu, D. and Loos, A. (eds.) Proceedings of the American Society for Composites - 30th Technical Conference, ACS 2015 2015. DEStech Publications Inc..

Record type: Book Section

Abstract

The concept of stress concentration suppression using thin-ply pseudo-ductile hybrid composites is presented in this paper. In previous works, it has been shown that it is possible to achieve high amounts of pseudo-ductility in Uni-Directional (UD) and multi-directional laminates. In this work, the requirements for thin-ply hybrid sublaminates to suppress/reduce notch sensitivity in quasi-isotropic laminates with an open hole is studied. A User Material subroutine (UMAT) has been developed in ABAQUS which can replicate the typical response of pseudo-ductile thin-ply hybrids. This UMAT was then used to study several idealised responses and find the important parameters controlling the fibre failure in notched specimens. The stress concentration factor in the 0° layer has been selected as a measure of notch sensitivity. The ratio of pseudo-ductile strain to initiation strain has also been found to be a useful parameter in comparing different fibre direction tensile responses. The stress concentration factors of the 0° layer found from two different tensile response shapes of UD sub-laminates were found to be very similar when they were plotted versus the ratio of pseudo-ductile strain over initiation strain. These results show that the stress concentration factor varies between 3 for linear elastic material response to 1 for sub-laminates with pseudo-ductile strain to initiation strain ratio of 3. This suggests that optimal structural response can be achieved with thin ply hybrids if the failure strain of the low strain material to high strain material is about 25%.

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More information

Published date: 30 September 2015
Keywords: stress concentration, structural optimization

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Local EPrints ID: 446753
URI: http://eprints.soton.ac.uk/id/eprint/446753
PURE UUID: a95df0de-a97b-45e7-a2e1-512417e3dfd1
ORCID for M. Jalalvand: ORCID iD orcid.org/0000-0003-4691-6252

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Date deposited: 19 Feb 2021 17:33
Last modified: 20 Feb 2021 02:59

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Contributors

Author: M. Jalalvand ORCID iD
Author: G. Czél
Author: M. R. Wisnom
Editor: X. Xiao
Editor: D. Liu
Editor: A. Loos

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