Support Elements with Negative Thermal Expansion

Abstract

Support elements with a high capability of thermal insulation are necessary in many low temperature applications. In a number of cases a fatigue resistance is required and several designs are facilitated if the support elements are capable of compensating undesired thermal expansion. This means that the materials used exhibit a reasonable negative thermal expansion. Carbon fiber composites angle -plied at ± 30° yield a coefficient of thermal expansion approaching half that of steel but with a negative sign.¹

The following investigations concentrate on the static and cyclic compressive strength of angle — plied carbon fiber tubes. An optimization is discussed which will allow a maximum compressive strength to be achieved at a maximum of negative thermal expansion. The compressive strength in all cases is higher than that of steel, even for ± 30° angle — plied composites.