Unified ring-compression model for determining tensile properties of tubular materials

Abstract

The stress-strain relation is the key mechanical properties in safety design and evaluation for tubular structures. However, conventional uniaxial tension and compression tests have some drawbacks and limitations for these structures. In the current investigation, a unified ring-compression model to acquire the stress–strain relation of tubular material is introduced based on the equivalent energy principle. In the model, a unified relation among strain energy, load, deflection, geometric parameters and material property parameters is proposed to depict the elastoplastic response during ring compression test. The model has only four undetermined parameters which can be calibrated by a few FEA (finite element analysis) calculations. The accuracy of the model has been verified within a wide range of imaginary materials by using FEA. Results show that both the forward-predicted load-deflection relation and the reverse-predicted stress-strain relations from the model are in excellent accord with the results from FEA. In addition, the model is verified with three homogeneous ductile materials by conducting ring compression and standard tensile tests. And it is applied in obtaining the hoop stress-strain relation of tubular zirconium alloy in the nuclear power engineering.