Low-velocity impact behaviour of titanium honeycomb sandwich structures

Abstract

Titanium honeycomb sandwich structures are gradually used in newly developed aircrafts in China. In this study, low-velocity impact tests on the titanium honeycomb sandwich structures were carried out to obtain the impact dynamic response and investigate the typical impact damage modes and parameters including the depths and diameters of the facesheet indentation and the core crushing region. The test results showed that the maximum contact force, the diameter and depth of the indentation had strong positive correlations to the impact energy. Numerical analysis was also conducted to study the low-velocity impact behaviour of the titanium honeycomb sandwich structures by using parametric finite element models that contained all the geometric and the structural details of the titanium honeycomb cores. The numerical results successfully captured the typical low-velocity impact damage modes of the titanium sandwich structures, similar to those observed in the tests. The predicted impact dynamic response also agreed very well with the test data. By using the validated finite element models, a parameter sensitivity study on the effects of the structural parameters on the low-velocity impact damage behaviour of the titanium sandwich structures was conducted. The parametric analysis results showed that the impactor diameter, the facesheet thickness and the core cell wall thickness had positive effect on the maximum contact force, and negative effect on the indentation depth, while the height of the honeycomb core had positive effect on the contact force, but little influence on the indentation depth.