Center for Advanced Vehicular Systems

Spotlight on Research - CAVS Hopkinson Bar System Established for High-Rate Testing

A material’s mechanical response to applied forces, that is, its resistance to applied forces may vary significantly, depending on the rate at which the forces are applied. Understanding and modeling of this phenomenon is important for understanding how structures such as buildings, bridges, vehicles, and the human body will respond when loaded at high rates.

To characterize a materials mechanical response to loads that are applied at high rates, the Center for Advanced Vehicular Systems utilizes the split Hopkinson bar test. The basic method and general theory for Hopkinson bar testing have been in use in some form since Dr. John Hopkinson’s initial testing in the 1870’s. CAVS currently has the capability to perform compression (left figure), tension and torsion testing (right) at strain rates that range from approximately 500/s to 5000/s on metals. This summer, CAVS will begin extending our testing capabilities to viscoelastic materials such as rubber, as well as, geologic materials such as sand.