A modified small punch test to investigate tensile properties

Abstract

Determination of tensile properties is essential for the design and strength assessment of structures. In this study, a modified small punch test (SPT), known as the single-stress small punch test (SS-SPT), was proposed to investigate the tensile properties of five ductile homogeneous materials, namely P91, Q245R, 316SS, 1045 steel, and 2024Al. The SS-SPT specimen was subjected to a single stress state when subjected to a punch force, similar to that of a uniaxial tensile test (UTT) specimen. Additionally, UTT and standard SPT were carried out to investigate the tensile properties of these materials. The thickness of failed standard SPT and SS-SPT specimens was measured using a scanning electron microscope (SEM) and the equivalent fracture strain was calculated. Correlation relationships between each type of SPT and UTT results were established. Experimental results indicated that both the SS-SPT and standard SPT demonstrated comparable accuracy in determining yield stress, ultimate tensile stress, and tensile elongation. However, the SS-SPT exhibited greater accuracy than the standard SPT in determining fracture strain due to direct measurement of the thinnest thickness from the fracture in failed SS-SPT specimens.