Prediction of buckling force in hourglass-shaped specimens

Abstract It is important to avoid buckling during low-cycle fatigue testing. The load dependent on the specimen shape, material properties, and testing machine. In present investigation of hourglass-shaped specimens importance diameter radius curvature examined. Diameters 5 7 mm are examined with a ratio 4, 6, 8. machine used an Instron 8800 elongated rods for climate chamber. This leads reduced stiffness compression A finite element model (in Abaqus) developed identify critical force. For specimens, means onset sideways movement, without drop in applied which typical conventional Euler buckling. movement identified experimentally by analysis data from extensometer cell. verified experiments fits within 0.6 − 11% depending ratio. smallest deviations obtained 7-mm-diameter deviation varying 3.3% between experiments. current done commercially available hot rolled structural steel bar Ø16 mm.