Experimentální stanovení vývoje plochy plasticity při cyklickém namáhání

Abstract

The dissertation deals with the experimental determination of the elastic region and its evolution under monotonic and cyclic loading. To determine the area of plasticity, a new methodology is presented for the implementation of experiments in the laboratory of the Department of Applied Mechanics, Faculty of Mechanical Engineering, VSB–TUO. The presented methodology uses a different approach in order to determine the specific yield strength, which is based on the criterion of the effective increment of plastic strain in each load axis. In a subsequent post-process, this termination criterion can be modified and arbitrarily tightened. The methodology is verified in conventionally fabricated specimens made of materials that are well described in the literature. Specifically, on Class C railway wheel steel and aluminium alloy 2124-T851. After validation, the methodology itself is applied to specimens fabricated by additive manufacturing, specifically the selective laser melting method. Thus, new initial yield surfaces are introduced for the 316L stainless steel, AlSi10Mg aluminium alloy, and Inconel 718 nickel-based superalloy samples that are fabricated additively. For the AlSi10Mg aluminium alloy and the Inconel 718 superalloy, subsequent yield surfaces under monotonic and cyclic loading with different prestress values are also presented.