Low velocity impact damage and its propagation under compressive load in curved, graphite/epoxy panels

Citation

Magaldi, Tony (1983) Low velocity impact damage and its propagation under compressive load in curved, graphite/epoxy panels. Engineer's thesis, California Institute of Technology. doi:10.7907/ekat-8g08. https://resolver.caltech.edu/CaltechETD:etd-09062006-082416

Abstract

An experimental study was conducted to investigate the influence of plate curvature on low-velocity impact damage and its propagation under compressive load in thick, Graphite/Epoxy laminates. High-speed photography coupled with the oblique-shadow moire technique indicates that initial impact damage and its subsequent propagation through delamination buckling act as separate mechanisms during the catastrophic failure process.

Results of an initial-postbuckling analysis for the buckling of thin cylindrical plates in axial compression were used to assess the effect of plate curvature on the conditions necessary for delamination buckling. Although curvature was found to increase the buckling load at the expense of a greater imperfection sensitivity, the effect is insignificant in thin shells if the plate width (i.e. initial delamination width) is small compared to the plate's radius.

When compared with the experimental and analytic findings of similar studies involving flat Gr/Ep laminates, results reveal that the 15 inch plate radius used for this series of experiments had a negligible influence on the inital damage and delamination propagation mechanisms.

Thesis Files