  Aerospace structures often experience high strain rate events such as
ballistic impact, crash, or crush. A material model has been developed that
enhances the capability to simulate the dynamic response of composite materials
under these loading conditions. The material model has been implemented into
the commercially available transient dynamic finite element code LS-DYNA as
MAT213. The model can simulate the nonlinear deformation, damage, and failure
that takes place in a composite under dynamic loading conditions. The specific
goal of this work is to characterize the MAT213 input for the representative
material. The specific composite material being examined consists of T700G
unidirectional carbon fibers and a low-melt PolyArylEtherKetone (LMPAEK)
thermoplastic resin system. It is formally referred to as Toray TC1225 LMPAEK
T700G. As the initial part of this work, this paper is focused on
characterizing the material parameters for the MAT213 deformation model based
on results obtained from multi-scale experimentation. The effort concentrated
on characterizing the in-plane material response suitable for use with thin
shell elements. For shell elements within MAT213, tabulated stress-strain
results from tension and compression tests in the longitudinal and transverse
directions and in-plane shear tests are required. Due to the difficulty of
measuring small strains in the transverse direction, a multi-scale testing
method was developed. Macro-scale testing is performed per the typical ASTM
methods while micro-scale testing uses a microscope along with smaller coupon
sizes to obtain the smaller strains in the transverse direction of each test.
For both testing methods, a VIC-2D camera and software for digital image
correlation analysis are used. Using the DIC combined with each test fixture,
reliable stress and strain data are collected.
