The paper presents the influence of plasma cutting process on the fatigue properties of structural elements, made of high strength steel S960Q. The specimens were manufactured from sheet steel using different cutting speeds, with the intent to analyse the influence of cut edge quality on fatigue strength. The experimental results show a relationship between the quality of cut edge and fatigue life with respect to chosen parametrs of the thermal cutting process.
COBISS.SI-ID: 11484438
A multi scale numerical approach for evaluation of crack initiation and propagation in thermally cut structural elements made of martensitic steel is presented. A numerical simulation of micro-crack initiation is based on the Tanaka-Mura micro-crack nucleation model, where individual grains of synthetic microstructure are simulated using the Voronoi tessellation. Three improvements are added to this model (multiple slip bands, micro-crack coalescence and segmented micro-crack) generation). Crack propagation is then solved on a macro scale model using LEFM.
COBISS.SI-ID: 13864982
Numerical simulation of micro-crack initiation that is based on improved Tanaka-Mura micro-crack nucleation model is presented. Numerical simulation of crack-initiation was performed with ABAQUS, using a plug-in that was written specially for handling micro-crack nucleation and coalescence. Since numerical model was directed at simulating fatigue properties of thermally cut steel with martensitic structure, edge properties of specimen were additionally inspected in terms of micro-structural properties, surface roughness and residual stresses.
COBISS.SI-ID: 13864726
The work discussed the impact of micro-defects on the resistance of welds against fatigue. With the rotating bending numerous samples of steel, with micro-defects in the various states, prepared by using simulation of thermal cycles of welding and by heat treatment in a furnace were tested. It has been experimentally studied the growth rate of small and large cracks. In work it is proved that the formation of cracks in the man-made micro-defects, whose size is comparable with the largest microstructural units of steel, a function of local residual stresses.
COBISS.SI-ID: 240161536
The work discussed numerical simulation of micro-crack nucleation, macro-crack formation and propagation. The proposed procedure encompasses all the microstructural peculiarities of investigated material. The procedure enables segmented micro-crack nucleation of potential micro-cracks on multiple slip bands of each grain, incorporates the accumulation of deformation energy in slip bands throughout simulation, and enables micro-crack coalescence into a macro-crack. High-cycle fatigue experiments on thermally cut steel confirm the validity of the proposed model.
COBISS.SI-ID: 247801856