Method for measuring and calculating tensile elongation of ductile metals

摘要

The present invention is a method for measuring and calculating tensile elongation of ductile metals on small diameter specimens. The method includes marking a tensile specimen with a pattern of gage markings at predetermined intervals. The tensile specimen is pulled to failure and then fitted together at the fracture. Distances between corresponding markings straddling the fracture are measured extending progressively outward from the fracture. From the measurements, elongation as a function of gage length is determined. End point elongation values (i.e., elongation at zero or near zero and infinite or very long gage lengths) are also determined. Determined elongations are scaled to reflect the values that would have been generated on a standard 0.5 inch diameter specimen. Based on the scaled elongation as a function of gage length and the end point elongation values, a value of elongation can be determined that represents a material property for FEA modeling the plastic strain behavior of a device.