Development and Validation of a Miniature Tensile Specimen for Determination of Mechanical Properties

In this work, a miniature tensile specimen with nominal dimensions of 3.0-mm gage length (GL), 1.5-mm gage width, and 0.5-mm thickness that was carved out of a 10.0-mm-diameter disk has been developed and standardized using analytical and experimental methods. The geometry of the miniature specimen, called ultra sub-size (USS), was optimized using finite element analysis to determine the fillet radius and appropriate geometrical tolerances for specimen dimensions like gage width and thickness. The methods of specimen preparation, gripping, and tensile testing with the use of digital image correlation for strain measurement were standardized. The 0.2 % offset yield strength, ultimate tensile strength, and uniform strain of different materials obtained using this specimen geometry were analyzed and compared with the results of ASTM sub-size (GL: 25 mm) and further sub-size geometry (GL: 12.5 mm). The results of this study show that USS tensile specimen geometry developed in this work can be reliably employed for mechanical property evaluation in situations where tensile testing using standard-size specimens is practically not possible.