TESTING AND MODELING HIGH STRAIN RATE FAILURE IN COMPOSITE MATERIALS

The use of fiber-matrix composite materials in military ordnance casings is of increasing interest to the U.S. Navy due to the potential for such casings to reduce collateral structure damage. In order to use fiber-matrix composite materials in such an application, the high strain rate failure characteristics of said materials must be well understood and capable of finite element (FE) implementation. This study evaluated the high strain rate behavior in relation to quasi-static behavior of a supplied carbon fiber material. Material samples were provided in three distinct composite layup orientations. High strain rate testing utilized a Charpy impact tester, and slow strain rate testing used a standard tensile tester. Experimental data revealed a rate-dependent failure strain in the composite matrix material and a rate-invariant failure strain in the carbon fiber. Material property data (including high strain rate effects) were passed into an impact specimen and tensile specimen ABAQUS FE model that used a pre-defined user subroutine capable of performing damage calculations on fiber-matrix composite materials. Additional impact tests used a load cell in order to create a time-dependent input force for the FE model (unique to each composite layup). The ABAQUS FE model produced results that were in agreement with the experimentally observed changes in composite layup material properties as functions of the applied strain rate.Office of Naval Researchhttp://archive.org/details/testingandmodeli1094562710Ensign, United States NavyApproved for public release; distribution is unlimited