Abstract
A mixed mode specimen is proposed for fracture mechanics characterisation of
adhesive joints, laminates and multilayers. The specimen is a double cantilever
beam specimen loaded with uneven bending moments at the two free beams. By
varying the ratio between the two applied moments, the full mode mixity range
from pure mode I to pure mode II can be generated for the same specimen geometry. The specimen allows stable crack growth. In case of large scale crack
bridging, mixed mode cohesive laws can be obtained by a J integral based approach. As a preliminary example, fracture of adhesive joints between two
glass-fibre laminates was studied. The mixed mode fracture resistance increased
with increasing crack length due to fibre cross over bridging, eventually reaching a steady-state level (R-curve behaviour). The steady-state fracture toughness
level increased with increasing tangential crack opening displacement. Cohesive
stresses were determined by a J integral approach. The deducted shear stress
was found to be relative high (≈ 20 MPa) in comparison with the normal stress
(≈ 1 MPa).
adhesive joints, laminates and multilayers. The specimen is a double cantilever
beam specimen loaded with uneven bending moments at the two free beams. By
varying the ratio between the two applied moments, the full mode mixity range
from pure mode I to pure mode II can be generated for the same specimen geometry. The specimen allows stable crack growth. In case of large scale crack
bridging, mixed mode cohesive laws can be obtained by a J integral based approach. As a preliminary example, fracture of adhesive joints between two
glass-fibre laminates was studied. The mixed mode fracture resistance increased
with increasing crack length due to fibre cross over bridging, eventually reaching a steady-state level (R-curve behaviour). The steady-state fracture toughness
level increased with increasing tangential crack opening displacement. Cohesive
stresses were determined by a J integral approach. The deducted shear stress
was found to be relative high (≈ 20 MPa) in comparison with the normal stress
(≈ 1 MPa).
Original language | English |
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Place of Publication | Roskilde |
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Publisher | Risø National Laboratory |
Number of pages | 35 |
ISBN (Print) | 87-550-3186-2 |
ISBN (Electronic) | 87-550-3187-0 |
Publication status | Published - 2004 |
Series | Denmark. Forskningscenter Risoe. Risoe-R |
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Number | 1394(EN) |
ISSN | 0106-2840 |
Keywords
- Risø-R-1394
- Risø-R-1394(EN)