On the same scale for stress the tensile true stresstrue str

On the same scale for stress, the tensile true stress-true strain curve is higher than the engineering stress-engineering strain curve. Explain whether this condition also holds for a compression test.

Solution

While performing a compression test the area of cross section of the particular specimen will increase as the specimen height will decrease , here volume will stay constant, as the load in increased. True stress we define as the ratio of the load to the instantaneous area of cross-section of the particular specimen the true stress is compression will be lower than the engineering stress for a given load to the specimen, here we are assuming that friction between the platens and the specimen is negligible.