Yielding of Mild Steel under Biaxial State of Uniform Stress

Abstract

This paper is a description of the experiments and discussions on the lower yield point of mild steel under biaxial state of uniform stress. The specimens used in the experiments are thin-walled tubes machined from a mild steel bar, which is considered practically to be isotropic in the virgin state. In the experiments the stresses at the yield point and the strain figures due to yielding are observed respectively. We obtained from the experiments various information on the yield point of mild steel. The conclusions are as follows: -The shearing stresses at the lower yield point under uniform stress are constant for a given material. Therefore, hydrostatic pressure does not affect the yield point, and intermediate principal stress does neither.