Life assessment using the finite element method of high-strength low-alloy steel samples exposed to low-cycle fatigue

Abstract

In the paper, based on the results of experimental research on the behavior of samples in the form of round smooth test specimens (STS) made of high strength low alloy steel (HSLA), Nionikral 70 (NN 70), under conditions of low cycle fatigue (LCF), a computational stress analysis was performed using numerical methods. Experimental investigations of the behavior of the samples were performed with controlled and fully reversible deformation ( /2 = const, R = min/ max = 1), according to the ISO 12106:2003 (E) standard. For computational analyses, the method of least squares (in the Excel program) and the finite element method (FEM) (in the SolidWorks program) were used. The behavior of HSLA steel during low cycle fatigue (LCF) simulation was analyzed in the Cosmos module of the SolidWorks program. On the basis of the analysis of the results of the stress deformation state and the determination of the life span through the isolines of the life span and comparison with the results of experimental tests, a graphic representation is given. Specific load cycles involving the entire round smooth test specimen ligament for a specific load in a wide range of LCF loads were analyzed. The analyzes showed the justification of the effort to solve the life assessment of steel subjected to low cycle fatigue (LCF) numerically. The results of experimental tests and simulation tests also gave us important data on understanding the LCF behavior of HSLA steel NN 70.