SHOCKLESS LOADING WITH RECOVERY FOR CHARACTERIZATION OF MATERIAL RESPONSE

A new recovery method for investigating material response to shockless (ramped) loading paths is described. The work makes use of a laser generated plasma piston that produces ramped loading at high strain rates ( > -10(7)/s). Large sample sizes are utilized to prevent reflected wave interactions. The overall deformation path is characterized by two transients: one at very high strain rate on the 5-10 nanosecond time scale and one at a lower strain rate occurring over a 1-2 microsecond timescale. It was found that a sufficiently large region of material experiences shockless loading conditions enabling recovery based characterization. The presence of two strain transients makes the method more applicable to comparative assessments between shockless and shock loading conditions.