Studies on the Fracture Mechanisms in Partially Penetrated Filament Reinforced Laminated Plates.

摘要

The overall objective of this research program has been to obtain information on the fracture mechanisms occurring in centrally impacted composite plates in order to establish design guidelines for plates to resist such impacts. A three dimensional orthotropic-material elastic analysis was performed to calculate the interlaminar shear stress in a (0 deg sub 5/90 deg sub 5/0 deg sub 5) glass/epoxy plate under central loading simulating a center point normal impact at 45.7 m/s (150 ft/sec) by a steel cylinder of diameter 9.7 mm and length 25.4 mm. The calculation was performed with the SAP IV finite-element computer code. Results indicated a considerable region where the estimated interlaminar shear strength was exceeded. Thus delamination would be expected to occur, as experimental studies have confirmed. The experimental delaminated areas do not correlate directly with the areas where the shear strength was exceeded in the elastic solution, because the stress distribution is altered during the delamination, which was not accounted for in the elastic solution.