High Strain Rate Effects for Composite Materials

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.