Numerical Analysis of Stress-Strain State and Crack Propagation in Welded Samples

Abstract

The numerical analysis of stress-strain state of low-alloyed welded steel samples test has been considered. The mechanical heterogeneity has been estimated by the micro hardness test. The stress-strain state analysis is based on the models of linear elasticity, which are described by Lame equations for displacement. In this case the samples are considered as perfect welded samples without any welding defects. The discretization of the system of equations is done through the finite element method, and the numerical realization of the method is performed on collection of free software FEniCS. The defects influence has been estimated by stochastic modelling of viscous crack growth. The data for crack size in weld and heat affected zone was obtain from microscopic observation, and for mechanical properties from microhardness testing. The result obtained shows that, the distribution of displacement in all samples are almost the same. Between the welded zone, the heat affected zone and the external elliptic zone, the Von Mizes stress is almost the same in all three samples. Concerning the crack growth, the velocity of it propagation in welded zone is higher as much again than that in the heat affected zone. This research is beneficial to welders, modellers of structures, researches as a whole.

Fatigue and Life Prediction of S135 High-Strength Drill Pipe Steel under Tension–Torsion Multiaxial Loading

“…Most of the components in engineering are subjected to multiaxial loads. Even if the component itself works under a uniaxial load, notches or corrosion defects of the complex lead to a multiaxial stress state in local area, which leads to fatigue failure [1][2][3][4][5][6]. Therefore, the study of multiaxial fatigue is much closer to the engineering practice than that of uniaxial fatigue, and how to prevent multiaxial fatigue failure becomes extremely important in engineering practice [7,8].…”