A novel test method based on small specimens for obtaining low-cycle-fatigue properties of materials

Abstract

In this study, a novel method for low-cycle-fatigue (LCF) tests on small funnel and Ring specimens to obtain the Manson–Coffin law of materials is proposed based on the median energy equivalence principle. It includes a method for solving the cyclic stress-strain relationship of the material according to the cycling stability curve of load amplitude–displacement amplitude, and another method for acquiring the conversion relationship between the measuring displacement amplitudes and local strain amplitudes of the specimen. LCF experiments under constant displacement amplitude loading were performed on small funnel and Ring specimens, as well as standard straight-round bar specimens of the two materials, G115 and 16Mn. The results indicated that the uniaxial cyclic stress–strain relationship and Manson–Coffin law results of the G115 and 16Mn materials obtained by the new method were highly consistent with those obtained by the traditional standard method.