Determination of True Stress-Strain (Hardening) Curve for the Fuel Rod Material

Abstract

A technique for determination of the true stress-strain curve for the material of fuel-element cladding is proposed under the assumption of isotropy of plastic hardening in the case of large plastic deformations. The material under the severe plastic deformation is described using the isotropic hardening plasticity. The method is based on the consistent application of three types of tests to determine the plastic resistance: 1) uniaxial tensile test of longitudinal specimens cut from the cladding, 2) compression with a high degree of plastic strain of the annular sample with an internal cylindrical rod, 3) compression of a segment cut from the annular specimen. The degree of strain of the ring wall in the second type of testing is determined from the results of the finite element simulation.