In support of efforts to numerically simulate the operation of nuclear weapons, pressure-sensitive materials used therein must be characterized, not only over a broad range of temperatures (approximately -65 to +70 °C), but at elevated pressures as well. Such materials include electrically active ceramics and composite encapsulants. Similarly, pressure-sensitive, dilatant target materials such as frozen soils must be characterized at both high-pressures and low-temperatures. To address these problems, we have designed and built a triaxial test cell capable of operating at temperatures as low as -65 °C and confining pressures up to 500 MPa and able to accept cylindrical test specimens having diameters and lengths up to 4.4 and 13.2 cm, respectively.

We determined that an externally cooled pressure vessel, composed of HP9-4-20 alloy steel and equipped with 12 coaxial feedthroughs, was feasible. Two specially designed load cells have been built for internal force measurements. Strains are measured using either standard strain gauges or LVDTs mounted in special fixtures, depending upon the nature of the specimen and magnitudes of the strains.

Collaboration with D. H. Zeuch, L. S. Costin, W. R. Wawersik, J. M. Grazier, D. R. Bronowski, and R. D. Hardy