TY - GEN
T1 - Barely visible impact damage evaluation of composite sandwich structures
AU - Singh, Abhendra K.
AU - Davidson, Barry D.
AU - Eisenberg, David P.
AU - Czabaj, Michael W.
AU - Zehnder, Alan T.
PY - 2010
Y1 - 2010
N2 - The nature of quasi-static indentation damage is studied in aluminum honeycomb core sandwich panels with eight ply, quasi-isotropic, graphite/epoxy face sheets. Parameters that are varied include the core thickness, core density, face sheet layup and indentor diameter. The majority of induced damage is in the vicinity of the barely visible threshold. The permanent dent in the panel is found to always be larger than the contact area of the indentor, and specimens with denser cores exhibit smaller dent diameters for a given dent depth. Regardless of specimen layup, delaminations occur essentially only at the 3rd, 5th, 6th and 7th interfaces. Stiffer cores, either in terms of a higher density or, for those cores considered, a smaller thickness, result in more face sheet delamination for a given indentation event. Regardless of the core, larger delaminations occur in face sheets that contain only 90° angle changes between adjacent plies in comparison to those that contain only 45° angle changes. Thus, when delamination area is considered as a damage resistance metric, a low density core with a [45/90/-45/0]s face sheet will provide the best results of those geometries considered. However, if dent area or dent depth is chosen as the damage metric, this geometry will provide the least damage resistance, and a high density core with a [±45/0/90]s face sheet is best. These and similar results are discussed in the context of choosing the most damage resistant structural configuration and how this translates to damage tolerance.
AB - The nature of quasi-static indentation damage is studied in aluminum honeycomb core sandwich panels with eight ply, quasi-isotropic, graphite/epoxy face sheets. Parameters that are varied include the core thickness, core density, face sheet layup and indentor diameter. The majority of induced damage is in the vicinity of the barely visible threshold. The permanent dent in the panel is found to always be larger than the contact area of the indentor, and specimens with denser cores exhibit smaller dent diameters for a given dent depth. Regardless of specimen layup, delaminations occur essentially only at the 3rd, 5th, 6th and 7th interfaces. Stiffer cores, either in terms of a higher density or, for those cores considered, a smaller thickness, result in more face sheet delamination for a given indentation event. Regardless of the core, larger delaminations occur in face sheets that contain only 90° angle changes between adjacent plies in comparison to those that contain only 45° angle changes. Thus, when delamination area is considered as a damage resistance metric, a low density core with a [45/90/-45/0]s face sheet will provide the best results of those geometries considered. However, if dent area or dent depth is chosen as the damage metric, this geometry will provide the least damage resistance, and a high density core with a [±45/0/90]s face sheet is best. These and similar results are discussed in the context of choosing the most damage resistant structural configuration and how this translates to damage tolerance.
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U2 - 10.2514/6.2010-2770
DO - 10.2514/6.2010-2770
M3 - Conference contribution
AN - SCOPUS:84855631270
SN - 9781600867422
T3 - Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
BT - 51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
PB - American Institute of Aeronautics and Astronautics Inc.
ER -