PSI - Issue 13

Mor Mega et al. / Procedia Structural Integrity 13 (2018) 123–130

129

M. Mega et al. / Structural Integrity Procedia 00 (2018) 000–000

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4. Conclusions

Knowledge of the resistance of a material to interlaminar failure is essential when designing structures fabricated from laminates. In this study, a delamination along a specific interface was investigated. Mixed mode fracture tough ness tests were carried out using BD specimens. From these tests, the critical load and delamination length at fracture were obtained and used to determine three mechanical stress intensity factors. In addition, thermal analyses were carried out to determine the residual stress intensity factors resulting from a temperature change during curing. Both stress intensity factors were superposed and used to obtain the critical energy release rate G ic , given in eq. (2) with K ( T ) III = 0, for each specimen. The phase angle, ψ given in eq. (5), was also obtained. Once all tests are completed, the experimentally obtained data will be used to determine a failure criterion in two and three dimensions. The results should provide a better understanding of the behavior of a delamination along this interface. These results may be used to improve the design and safety of a structure containing this interface for this material. In the future, quasi-static, as well as fatigue delamination propagation tests will be carried out using the double cantilever beam (DCB), calibrated end loaded split (C-ELS) and mixed mode end loaded split (MMELS) specimens for nearly pure mode I, mode II and mixed mode deformation, respectively. The quasi-static test results will be compared with the results obtained using the BD specimen. The results from the fatigue tests will allow for evaluation of the delamination growth rate and propagation parameters for the di ff erent deformation modes.

5. Acknowledgment

This research is supported by the Israel Ministry of Science, Technology and Space.

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