Study of post-impact behaviour of thin carbon/epoxy laminates subject to fatigue tensile loading

• Published in: International journal of fatigue Vol. 148; p. 106134
• Main Authors: Rogani, A., Navarro, P., Marguet, S., Ferrero, J-F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.07.2021; Elsevier BV; Elsevier
• Subjects: Carbon; Digital image correlation; Digital imaging; Drop tests; Engineering Sciences; Explicit F.E modelling; Fatigue; Fatigue failure; Fatigue tests; Finite element method; Impact damage; Laminates; Layers; Materials fatigue; Mechanical engineering; Mechanics; Propagation; Semi-continuous approach; Tensile tests; Woven composites; Fatigue; Explicit F.E modelling; Digital image correlation; Semi-continuous approach; Woven composites; explicit F.E modelling; fatigue; semi-continuous approach; digital image correlation
• ISSN: 0142-1123; 1879-3452; 1879-3452
• DOI: 10.1016/j.ijfatigue.2020.106134

•Post-impact damage propagation in tension in woven carbon/epoxy laminates is studied.•The monitoring of damages is based on Digital Image Correlation and RX Tomography.•The propagation of cracks is governed by the resin damages and by delamination.•A FEM based on Semi-Continuous strategy is developed to represent these propagations.•This new modelling strategy well represent the damage initiation and propagation. This article concerns the experimental and numerical study of post-impact damage propagation in thin carbon/epoxy woven composite laminates loaded in fatigue tension. Low velocity normal drop weight impact tests are first performed. Post-impact fatigue tensile tests are then carried out. They are controlled in displacement. The monitoring is based on Digital Image Correlation and RX tomography. The influence of the impact energy and the tensile fatigue loading on the post-impact damage propagation is studied. The damage propagation is governed by matrix damage, with the emergence of tows/resin splittings and intra-tows crackings as well as delamination when the plies have different orientations. When the impact energy or the displacement level increases, the post-impact damage initiates sooner and propagate faster. In some cases, that can lead to a quasi-instantaneous failure identical to that observed for quasi-static tensile loading. The FEM based semi-continuous approach, initialy developped for the modelling of impact damage, is extended to fatigue loading for carbon/epoxy woven laminates. Fatigue damage laws, based on experimental observations are implemented. The modelling well correlates the experimental results in terms of damage propagation scenario and speed depending on the number of cycles for laminates made up of plies with the same orientation.