On the Low-Velocity Impact and Quasi-Static Indentation Studies of Nomex™ Honeycomb Composite Sandwich Panels

An experimental-numerical methodology for investigation of quasi-static indentation and low-velocity impact on sandwich panels with composite skins and Nomex™ Honeycomb core is presented. Sandwich panels with glass/epoxy skins and a NomexTM honeycomb core were modeled by a three-dimensional finite element model implemented in ABAQUS/Explicit. The model was validated with experimental tests by comparing numerical and experimental results. A dedicated focus on numerical models of this research is presented. Particular attention has been paid to verify the modeling of core behavior during the last part of low-velocity impact loading. The comparison has not only been based on a load–displacement and load time history curves, but has been further exemplified by detailed photographical images throughout the whole loading process and the local behavior of the cells crushing. The influence of various parameters has been also evaluated from a numerical point of view. Results show that fine micromechanical models based on shell elements give good correlation with honeycomb compression tests for Nomex™ honeycombs. Also the reference Finite Element of briefly FE numerical model demonstrates its capability to accurately reproduce the shape of the local damage of the panel. In other words, the calibrated micromechanical model is obtained to predict both quasi-static and low-velocity impact behavior. The mentioned model could be used for structural optimization with enhanced accuracy in contrast to conventional macro-mechanical models. The calibrated model is used to predict the cell size effect, friction and also geometric scale.