Abstract
The majority of mechanical components in nuclear power plants must be designed to withstand extreme cyclic loading conditions. In fact, when these components are subjected to low cycle fatigue, machining imperfections are considered one of the most significant factors limiting their service life. In the present work, using finite element analysis, a methodology has been suggested to predict the fatigue life of cylindrical parts made of 316 SS, at ambient temperature, under nominal strain amplitude ranging from ± 0.5 to ±1.2% with various surface roughness conditions. Two different multiaxial strain-life criteria have been considered to estimate the fatigue life, namely Brown-Miller and maximum shear strain. The comparison between the predicted and the experimental fatigue lifetimes has revealed that the adopted multiaxial strain life criteria can successfully estimate the fatigue life of 316 SS grade under uniaxial loading conditions. Furthermore, it has been found that the fatigue life decreases as the surface roughness average value increases, which indicates that surface regularities have a significant impact on low cycle fatigue life. Therefore, the proposed methodology is found to be capable of assessing the impact of surface roughness on the fatigue life of this specific steel in the low cycle fatigue regime.
Highlights
With the increasing global demand for energy generation, mechanical components, in the nuclear power plant industries, are expected to operate at extreme temperature and pressure loading patterns
It can be observed that the estimated low cycle fatigue lives are generally conservative, which is evident that BrownMiller and maximum shear strain multiaxial criteria can safely predict the low cycle fatigue life of cylindrical specimens made of 316 Stainless Steel (SS), at room temperature, and subjected to fully reversed uniaxial tension-compression cyclic loadings
The low cycle fatigue behavior was numerically investigated using ABAQUS software, for cylindrical specimens made of 316 Stainless Steel subjected to nominal strain amplitude ranging from ± 0.5 to ± 1.2%, at room temperature
Summary
With the increasing global demand for energy generation, mechanical components, in the nuclear power plant industries, are expected to operate at extreme temperature and pressure loading patterns. Coffin and Manson [4,5] suggested a linear equation, in the logarithmic scale, for low cycle fatigue regime that correlates the plastic strain amplitude to the number of reversals to failure. The 316 Austenitic Stainless Steel (SS) is the most widely used material for engineering components in the nuclear power plant industries [8], such as in the nuclear reactors, owing to outstanding mechanical and low cycle fatigue properties, as well as good anti-corrosion resistance, at low and high temperatures [8,9]. A different methodology is used in the present paper; the cyclic stress-strain behavior has been initially evaluated, using finite element analysis (FEA) in the ABAQUS-Standard software [10], for dog-bone shaped specimens made of 316 SS and subjected to uniaxial low cycle fatigue loading, at room temperature. By using Fe-Safe software [15], the effect of the surface imperfection on the cyclic life has been studied for various intervals of surface roughness average and applied strain amplitude levels
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