Abstract
Compression After Impact (CAI) strength is critical to the safety and weight of carbon fibre aircraft. In this paper, the standard aerospace industry practice of using separate analyses and tests for panel buckling and CAI strength is challenged. Composite panels with a range of stacking sequences were artificially delaminated and subject to compression testing in a fixture that allowed local sublaminate and global panel buckling modes to interact. Compared to panels without delamination, interaction of buckling modes reduced panel buckling strains by up to 29%. Similarly, compared to delaminated panels restrained against panel buckling, interaction reduced delamination propagation strains by up to 49%. These results are the first to indicate that restriction of interaction during CAI testing is unconservative and therefore potentially unsafe. A novel integration of an analytical Strip model, for sublaminate buckling driven delamination propagation, and a Shanley model, for determining increased local strain due to sublaminate-buckling-induced panel curvature, is used to calculate the reduction in strength due to buckling mode interaction. Assuming a typical sublaminate post to pre-buckling stiffness ratio of 0.65, the difference in integrated model and experimental results is <11% – a level of accuracy that will allow the integrated model to drive initial design studies.
| Original language | English |
|---|---|
| Pages (from-to) | 326-334 |
| Number of pages | 9 |
| Journal | Composite Structures |
| Volume | 171 |
| Early online date | 6 Mar 2017 |
| DOIs | |
| Publication status | Published - 1 Jul 2017 |
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Keywords
- Buckling
- Compression after impact
- Delamination
- Strength
ASJC Scopus subject areas
- Ceramics and Composites
- Civil and Structural Engineering
Cite this
Compressive strength of composite laminates with delamination-induced interaction of panel and sublaminate buckling modes. / Rhead, Andrew T.; Butler, Richard; Hunt, Giles W.
In: Composite Structures, Vol. 171, 01.07.2017, p. 326-334.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Compressive strength of composite laminates with delamination-induced interaction of panel and sublaminate buckling modes
AU - Rhead, Andrew T.
AU - Butler, Richard
AU - Hunt, Giles W.
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Compression After Impact (CAI) strength is critical to the safety and weight of carbon fibre aircraft. In this paper, the standard aerospace industry practice of using separate analyses and tests for panel buckling and CAI strength is challenged. Composite panels with a range of stacking sequences were artificially delaminated and subject to compression testing in a fixture that allowed local sublaminate and global panel buckling modes to interact. Compared to panels without delamination, interaction of buckling modes reduced panel buckling strains by up to 29%. Similarly, compared to delaminated panels restrained against panel buckling, interaction reduced delamination propagation strains by up to 49%. These results are the first to indicate that restriction of interaction during CAI testing is unconservative and therefore potentially unsafe. A novel integration of an analytical Strip model, for sublaminate buckling driven delamination propagation, and a Shanley model, for determining increased local strain due to sublaminate-buckling-induced panel curvature, is used to calculate the reduction in strength due to buckling mode interaction. Assuming a typical sublaminate post to pre-buckling stiffness ratio of 0.65, the difference in integrated model and experimental results is <11% – a level of accuracy that will allow the integrated model to drive initial design studies.
AB - Compression After Impact (CAI) strength is critical to the safety and weight of carbon fibre aircraft. In this paper, the standard aerospace industry practice of using separate analyses and tests for panel buckling and CAI strength is challenged. Composite panels with a range of stacking sequences were artificially delaminated and subject to compression testing in a fixture that allowed local sublaminate and global panel buckling modes to interact. Compared to panels without delamination, interaction of buckling modes reduced panel buckling strains by up to 29%. Similarly, compared to delaminated panels restrained against panel buckling, interaction reduced delamination propagation strains by up to 49%. These results are the first to indicate that restriction of interaction during CAI testing is unconservative and therefore potentially unsafe. A novel integration of an analytical Strip model, for sublaminate buckling driven delamination propagation, and a Shanley model, for determining increased local strain due to sublaminate-buckling-induced panel curvature, is used to calculate the reduction in strength due to buckling mode interaction. Assuming a typical sublaminate post to pre-buckling stiffness ratio of 0.65, the difference in integrated model and experimental results is <11% – a level of accuracy that will allow the integrated model to drive initial design studies.
KW - Buckling
KW - Compression after impact
KW - Delamination
KW - Strength
UR - http://www.scopus.com/inward/record.url?scp=85015826147&partnerID=8YFLogxK
UR - https://doi.org/10.1016/j.compstruct.2017.03.011
UR - https://doi.org/10.1016/j.compstruct.2017.03.011
U2 - 10.1016/j.compstruct.2017.03.011
DO - 10.1016/j.compstruct.2017.03.011
M3 - Article
VL - 171
SP - 326
EP - 334
JO - Composite Structures
JF - Composite Structures
SN - 0263-8223
ER -