We have been developing the capability to characterize the high strain rate response of continuous fiber polymer composites. The data presented cover strain rates from 0/s to 3000/s. A combination of test machines and specimen geometries was investigated. Strain rates from 0 to 100/s were generated using conventional and high-speed hydraulic test machines. Strain rates from 10 to 1000/s were generated using a high-energy drop tower, and rates from 1000 to 3000/s were generated using a split Hopkinson bar. Strain rates above 100/s have only been generated for uniaxial compression. Our efforts have primarily focused on developing the high-energy drop tower for these purposes. Specimen geometries for compression include tapered cubes, one-inch tubes, and solid rods. For tension, a smaller 1.27-cm-diameter version of our 5.08-cm-diameter multiaxial test specimen was developed and has been successfully used at strain rates up to 100 per second. Fixtures were also developed for performing high strain rate shear testing and through thickness penetration studies of composite plates. The objective of these experiments is to develop dynamic material models for use in finite element design tools. This presentation will focus on the methods and results obtained from this study.

Matrix-dominated mechanical properties of unidirectional fiber composite laminae were determined from hoop-wound tube specimens and cylindrical rods fabricated from both wet filament winding and prepreg material systems. Longitudinal shear modulus and strength as well as transverse Young's modulus, transverse tensile strength, and transverse compressive strength were obtained from a thin-walled tube specimen using a new fixturing design. Lamina properties are presented for several carbon fiber/epoxy composite materials. Longitudinal shear moduli were measured for both tubes and rods in torsion. Results obtained in the linear-elastic regimes above and below the glass transition temperature (Tg) of the matrix phase were compared with micromechanics predictions. Although agreement between predicted and measured shear moduli was reasonable below Tg, for some composites large discrepancies were observed at temperatures above Tg of the neat matrix material.

The shear strengths of two ductile epoxies are obtained from solid cylinder torsion using a data reduction scheme. The results are in quantitative agreement with shear data from torsion of thin-walled tubes of the same materials, particularly with regard to the coincidence of the peak yield stress and strain. The described technique is useful for characterizing ductile material behavior in shear using a simple, solid cylinder specimen.