Behavior of Materials under Dynamic Combined Stresses of Torsion and Tension

Abstract

The paper is concerned with the experiment on the multi-axial stress-strain relations in time dependent materials. In order to examine the dynamic behavior of solid materials under combined stresses, a testing machine for applying the impulsive torque and tension simultaneously to the specimen has been desined. Experiments are performed with various ratios of torque to axial force by the e-quipment. During the loading process, the load ratios are kept constant, and we can obtain almost proportional loading. Equivalent strain rates are about 30 sec⁻¹ to 50 sec⁻¹. The dynamic yield surfaces in the (σ — τ plane are ellipse like Von Mises’s yield surface in static loading, but the radii are larger than the static one and time dependent property is found clearly in biaxial loading too. The flow lure can be expressed by the Perzyna type formula.