Details
| Original language | English |
|---|---|
| Article number | 1153 |
| Journal | MATERIALS |
| Volume | 12 |
| Issue number | 7 |
| Publication status | Published - 1 Apr 2019 |
Abstract
Microcrack formation and delamination growth are the main damage mechanisms in the fatigue of composites. They lead to significant stiffness loss, introduce stress concentrations and can be the origin of subsequent damage events like buckling or fibre breakage, especially in case of shear and compression stresses during load reversal. Fatigue experiments of carbon fibre reinforced laminates were conducted at several stress ratios and analysed in terms of crack and delamination growth. These investigations were accompanied by microscopic imaging, digital image correlation and finite element modelling to take into account the effects of residual stresses and crack closure. It was found that residual stresses significantly change the local stress ratio in off-axis layers and lead to residual crack opening of inter fibre cracks. These cracks remain open and close under high compression loadings only. Furthermore, crack formation under pulsating compression loading turned out to be driven by residual stresses leading to perpendicular cracks as observed under pure tension loading. The experimental findings further confirm the severe detrimental effect of tension-compression loading on crack formation and delamination growth compared to pulsating tension-tension or compression-compression loads.
Keywords
- CFRP, Composite, Crack growth, Delamination, Failure, Fatigue, Fracture, Load reversal, Microcracking, Residual stresses
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
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In: MATERIALS, Vol. 12, No. 7, 1153, 01.04.2019.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Influence of Reversed Fatigue Loading on Damage Evolution of Cross-Ply Carbon Fibre Composites
AU - Just, Gordon
AU - Koch, Ilja
AU - Brod, Martin
AU - Jansen, Eelco
AU - Gude, Maik
AU - Rolfes, Raimund
N1 - Funding information: This research was funded by the German Research Foundation (DFG) within the project number 281870175.
PY - 2019/4/1
Y1 - 2019/4/1
N2 - Microcrack formation and delamination growth are the main damage mechanisms in the fatigue of composites. They lead to significant stiffness loss, introduce stress concentrations and can be the origin of subsequent damage events like buckling or fibre breakage, especially in case of shear and compression stresses during load reversal. Fatigue experiments of carbon fibre reinforced laminates were conducted at several stress ratios and analysed in terms of crack and delamination growth. These investigations were accompanied by microscopic imaging, digital image correlation and finite element modelling to take into account the effects of residual stresses and crack closure. It was found that residual stresses significantly change the local stress ratio in off-axis layers and lead to residual crack opening of inter fibre cracks. These cracks remain open and close under high compression loadings only. Furthermore, crack formation under pulsating compression loading turned out to be driven by residual stresses leading to perpendicular cracks as observed under pure tension loading. The experimental findings further confirm the severe detrimental effect of tension-compression loading on crack formation and delamination growth compared to pulsating tension-tension or compression-compression loads.
AB - Microcrack formation and delamination growth are the main damage mechanisms in the fatigue of composites. They lead to significant stiffness loss, introduce stress concentrations and can be the origin of subsequent damage events like buckling or fibre breakage, especially in case of shear and compression stresses during load reversal. Fatigue experiments of carbon fibre reinforced laminates were conducted at several stress ratios and analysed in terms of crack and delamination growth. These investigations were accompanied by microscopic imaging, digital image correlation and finite element modelling to take into account the effects of residual stresses and crack closure. It was found that residual stresses significantly change the local stress ratio in off-axis layers and lead to residual crack opening of inter fibre cracks. These cracks remain open and close under high compression loadings only. Furthermore, crack formation under pulsating compression loading turned out to be driven by residual stresses leading to perpendicular cracks as observed under pure tension loading. The experimental findings further confirm the severe detrimental effect of tension-compression loading on crack formation and delamination growth compared to pulsating tension-tension or compression-compression loads.
KW - CFRP
KW - Composite
KW - Crack growth
KW - Delamination
KW - Failure
KW - Fatigue
KW - Fracture
KW - Load reversal
KW - Microcracking
KW - Residual stresses
UR - http://www.scopus.com/inward/record.url?scp=85065636735&partnerID=8YFLogxK
U2 - 10.3390/ma12071153
DO - 10.3390/ma12071153
M3 - Article
AN - SCOPUS:85065636735
VL - 12
JO - MATERIALS
JF - MATERIALS
SN - 1996-1944
IS - 7
M1 - 1153
ER -