To investigate off-axis cracks in composite laminates and their effect on stiffness and hysteretic energy dissipation, fatigue tests were instrumented with automated crack detection to test damage onset and progression. It was found that the onset of stiffness loss correlates well with the onset of matrix cracks, but not with the dissipated energy. To study the transition between experimentally observed damage modes occurring at the micro-scale, the experimentally obtained dissipated energy was compared with Carraro’s model, which predicts this transition based on local stresses. The results show a correlation between the absolute level of dissipated energy and the micro-damage modes.
Bibliographische NotizFunding Information:
Part of this work has been performed within the COMET-project Experimental and numerical analysis of the damage tolerance behaviour of manufactured induced defects and bonded repairs in structural aerospace composite parts (project-no.: VI-3.04) at the Polymer Competence Center Leoben GmbH (PCCL, Austria) within the framework of the COMET-program of the Federal Ministry for Transport, Innovation and Technology and the Federal Ministry for Digital and Economic Affairs with contributions by Montanuniversität Leoben (Chair of Designing Plastics and Composite Materials) and MAGNA Powertrain Engineering Center Steyr GmbH CO KG. The PCCL is funded by the Austrian Government and the State Governments of Styria, Lower Austria and Upper Austria .
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