Dynamic material property measurements using an improvement of the freely expanding ring technique

Improvements to the expanding ring test for determination of dynamic material properties are described. The improvements alleviate previous difficulties associated with double-differentiation of ring displacement-time data. The technique is illustrated utilizing 6061-0 and 6061-T6 aluminum rings expanded well into the plastic range at strain rates up to 104/s. Two-dimensional numerical investigations of the expansion process qualitatively predict observed results and clarify the range over which data is useful for determining material properties