Engineering stress is the ratio of load over the unstressed cross section area. Engineering strain is the ratio of change in length over the unstressed length. The elastic modulus is the ratio of engineering stress over engineering strain. Engineering stress and strain ignores the change in cross section area and length as a load is applied.
Calculate the Ramberg Osgood stress strain equation coefficients.
The Ramberg Osgood equation is an approximate model of strain versus stress for a work hardening material. The Ramberg Osgood equation is continuous, and does not have a distinct yield point, or a yield plateau. The elongation is initially elastic, and becomes progressively more plastic as the load is applied.
Calculate true stress and strain, and engineering stress and strain.
Engineering stress and strain are calculated from the unstressed material length and cross section area. True stress and strain are calculated from the deformed length and cross section area.