Mixed mode fracture toughness: An empirical formulation for determination in asymmetric DCB specimens
✍ Scribed by V. Mollón; J. Bonhomme; J. Viña; A. Argüelles
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 533 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0141-0296
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✦ Synopsis
Asymmetric DCB specimens (ADCB), in which the crack plane is out of the laminate midplane, are simple and useful test configurations to produce a mixed mode load state at the crack tip of the samples. This test configuration is as simple as pure mode I tests. However, the analytical procedures developed in the ASTM D5528-01 standard to calculate G I are no longer valid to analyze the ADCB specimen. In this test configuration, the position of the crack plane controls the mode I and mode II load levels at the crack tip.
In this work an empirical formulation, based on Finite Element Modelling (FEM), has been developed in order to calculate G I /G and G II /G (where G = G I +G II ) in ADCB specimens. On the other hand, the Modified Beam Theory (MBT) has been adapted by means of experimental calibration to allow the calculation of G for this test configuration. These formulations have been validated by means of FE modelling for different crack plane positions. Finally, the formulations developed in this paper were used to calculate G I and G II in experimental results on glass fibre epoxy laminates and the obtained results were compared with formulations developed by other authors. A good agreement was found among the different analytical, empirical, and numerical methods studied in this paper.