Theoretical Basis of Fractographic Methods and Their Application in Fracture Modelling for Cr-Ni Steels

Abstract

Fractographic methods derive their knowledge from Euclidean geometry, set theory, metric theory and chaos theory. In engineering technology, the fractography is primarily used for modeling of fatigue and intergranular fractures. As such defects are not smooth due the principle of their origin, they cannot be described using ordinary mathematical tools. However, if the conditions of self-similarity are met, fractal geometry means can describe various irregular, incomprehensible, crooked or fragmented geometric shapes. Fractographic description of the fracture profile allows more accurate quantification of fractures and it also enables identifying possible causes of their initiation. This study contains several examples of specific cases of Cr-Ni steel failures and a basic explanation of their fractographic description.

Surface roughness of thermally treated wood cut with different parameters in CNC router machine

“…During chip removal, the cutter tool rotates around its axis and the individual teeth gradually enter through the workpiece, which moves simultaneously against the movement of the tool (Prokeš 1982). The blades of the milling cutter gradually remove chips from the machined material (Kvasnová et al 2017;Klopanová et al 2017). Processing wood materials with different anatomical structures by using different parameters on these machines, where the spindle speed and feed rate can be precisely adjusted compared to conventional machines, yields different results on the cut surfaces.…”

Effect of technological and material parameters on final surface quality of machining when milling thermally treated spruce wood

“…During chip removal, the milling head rotates around its axis (the main movement process) and the individual teeth gradually enter through the workpiece, which moves simultaneously against the movement of the tool (the secondary movement process) (Prokeš 1982). The individual blades of the milling cutter gradually remove short chips from the machined material, while the milling process is not interrupted (Lisičan 1996;Kvasnová et al 2017;Klopanová et al 2017).…”