Micromechanical Coupled Study of Crack Growth Initiation Criterion in Pressure Vessel Steel

Abstract

К лю чевы е слова: комплексное микромеханическое моделирование, доля объемных пустот, метод конечных элементов, критерий развития трещины.Introduction. Micromechanism of ductile fracture o f most metals and alloys includes void nucleation, growth and coalescence. In steels, voids nucleate at non-metallic inclusions and second-phase particles. Micromechanical approach to fracture mechanics has been introduced in an effort to describe the process of fracture in a way that is as close to the actual phenomena in a material as possible. Such an approach is based on the models that account for and quantify the process o f microscopic damages, in order to predict macroscopic failure.Micromechanical approach to the analysis o f ductile fracture requires combined experimental and numerical procedure. According to the uncoupled micromechanical damage models, the damage parameter is calculated in postprocessing phase of the finite element (FE) analysis. In the coupled micromechanical models, one or more damage parameters are calculated to

Computational fracture mechanics: An overview from early efforts to recent achievements

“…On one hand side, it was relatively simple model for brittle fracture, ie, cleavage, whereas more complex mechanisms of ductile fracture were modelled as a process of void nucleation, growth, and coalescence, which is the focus here. In this chapter, numerical methods, used for simulation of ductile fracture process, are presented as a compilation of previously accomplished research, followed by an overview of more recent results …”

“…The more recent methods and approaches are focused to specific problems, including void coalescence criterion, detailed microstructural analysis, and the effect of size, shape, and distribution of voids . These micromechanical models have been successfully applied to several classes of problems, including pressure vessels, pipelines, and welded joints …”

“…34 The more recent methods and approaches are focused to specific problems, including void coalescence criterion, detailed microstructural analysis, and the effect of size, shape, and distribution of voids. 121,122 These micromechanical models have been successfully applied to several classes of problems, including pressure vessels, [123][124][125] pipelines, 126,127 and welded joints. 128,129 Modelling of ductile fracture includes void nucleation around inclusions and second-phase particles, followed by their growth and coalescence (Figure 13).…”

Micromechanical fracture analysis of high strength steel weldments

“…The most recent methods and approaches are focused to some of the problems, including void coalescence criterion, more detailed microstructural analysis, influence of various quantities (size, shape and distribution of voids)[69,70]. These micromechanical models have been successfully applied to several classes of problems, including pressure vessels[71][72][73], pipelines, inhomogeneous materials, and welded joints[18,74,75]. One of the most recent models is CGM (Complete Gurson Model)[17,26].…”

“…Tvergaard Determination of the critical void volume fraction f c is very important for application of Equation (4.15) and Equation(4.16). Different techniques are proposed in[72,98,100,101] for determining its value.…”