Test specimen/jaw assembly that exhibits both self-resistive and

Abstract

Apparatus either for a specimen that is to be held in a jaw assembly of, for example, a dynamic thermal-mechanical testing system or for the jaw assembly itself wherein the specimen or jaw assembly, respectively, exhibits both self-resistive and self-inductive heating whenever a sufficiently large alternating (AC) electrical current is passed serially therethrough. In one embodiment, the specimen (200, 300) is fabricated from a material which undergoes self-resistive heating and in which suitable levels of eddy currents can be induced by and also includes an appropriately shaped heating section (205, 206; 305, 306) situated near each of two opposing ends thereof. In another embodiment, a metallic conductor (403, 403'; 503) is fabricated from a material which undergoes self-resistive heating, in which suitable levels of induced eddy currents can occur and which contains appropriately shaped and sized heating sections (406, 407; 406', 407'; 512, 512'). Such a conductor is situated in each jaw assembly (401, 401'; 500). Each conductor abuts against and is in electrical contact with an opposing end-face of a specimen. Whenever current is passed through either embodiment, these heating sections (205, 206; 305, 306; 406, 407; 406', 407'; 512, 512') will exhibit both self-resistive and self-inductive heating wherein the amount of additional heat generated through self-induction and propagating into the ends of the specimen can be set to compensate for heat loss that would otherwise occur from the ends of the specimen into the neighboring jaw assembly thereby assuring that substantially no longitudinal temperature gradients are established either along the mid-span region of the specimen or along the entire specimen while heating current passes therethrough. The size and shape of each such heating section governs the amount of additional heat that will be generated therein.