Low velocity impact of combination Kevlar/carbon fiber sandwich composites

Experimental and numerical study on the low-velocity impact behavior of foam-core sandwich panels

Ballistic impact of GLARE™ fiber–metal laminates

Ballistic impact experiments of metallic sandwich panels with aluminium foam core

Collapse modes in aluminium honeycomb sandwich panels under bending and impact loading

Dynamic models for low-velocity impact damage of composite sandwich panels – Part A: Deformation

Dynamic models for low-velocity impact damage of composite sandwich panels – Part B: Damage initiation

An analytical solution for the ballistic limit of a honeycomb plate subjected to normal impact by blunt and spherical projectiles is presented. The solution involves a three-stage, perforation process that results in complete perforation of the sandwich. Stages 1–3 describe perforation of the top facesheet, honeycomb core, and bottom facesheet, respectively. Residual velocities in Stages 1 and 2 are found from energy balances between each stage. The plastic work dissipated in deformation and fracture at each stage is approximated from the solution of the previous stage. Shear forces are transmitted in the bond between facesheets and honeycomb core. The predicted ballistic limits are found to be within 5% of the measured ballistic limits for sandwich plates perforated by the blunt and spherical projectiles. The lateral extent and deformation of the damaged facesheets are also found to be within 34 and 51% of limited test results, respectively. It has also been found that most of the work is dissipated in perforation of the bottom facesheet during impact. The work to perforate the bottom facesheet by the blunt and spherical projectiles accounts for 63–85 and 55% of the initial kinetic energy, respectively. Therefore, the perforation resistance of the bottom facesheet, rather than the top facesheet or honeycomb core, would be an important parameter in determining the perforation resistance of the entire sandwich panel.

Perforation of honeycomb sandwich plates by projectiles

Analytical solutions for the low-velocity impact damage of composite sandwich panels are found by considering systems of discrete masses, springs and constant-force dashpots. Equivalent spring and dashpot forces for the sandwich panel are derived from the static load-indentation response and adjusted with dynamic material properties of the facesheet and core. Predictions of the maximum impact force are about 15% higher than experimental values, which is the same order of accuracy that is obtained from the static load-indentation analysis. Damage initiation due to tensile failure by hemispherical-nose shape projectiles and shear failure by blunt projectiles are examined. Predicted tensile and shear failure loads are about 20% higher than experimental results.

http://jsm.sagepub.com/content/3/2/130.full.pdf

Kyong S. Park

Papers

Dynamic models for low-velocity impact damage of composite sandwich panels – Part A: Deformation

Dynamic models for low-velocity impact damage of composite sandwich panels – Part B: Damage initiation

Perforation of honeycomb sandwich plates by projectiles

Modeling Low-Velocity Impact Damage of Composite Sandwich Panels