Simulation of Slip-Oxidation Process by Mesh Adaptivity in a Cohesive Zone Framework.

Michal Sedlak Mosesson,Pål Efsing,Bo Alfredsson

doi:10.3390/ma14133509

Michal Sedlak Mosesson, Pål Efsing + Show 1 more

Open Access

https://doi.org/10.3390/ma14133509

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Abstract

Adaptive oxide thickness was developed in a cohesive element based multi-physics model including a slip-oxidation and diffusion model. The model simulates the intergranular stress corrosion cracking (IGSCC) in boiling water reactors (BWR). The oxide thickness was derived from the slip-oxidation and updated in every structural iteration to fully couple the fracture properties of the cohesive element. The cyclic physics of the slip oxidation model was replicated. In the model, the thickness of the oxide was taken into consideration as the physical length of the cohesive element. The cyclic process was modelled with oxide film growth, oxide rupture, and re-passivation. The model results agreed with experiments in the literature for changes in stress intensity factor, yield stress representing cold work, and environmental factors such as conductivity and corrosion potential.

Highlights

When assessing nuclear power plant life, stress corrosion cracking (SCC) plays an important role
The model category considered in the current work, is denoted slip-dissolution models [3,4] where the anodic dissolution is very high at the crack tip compared to the sides of the crack, which creates a growing sharp crack
More phenomenological approaches are available with couplings between fracture mechanics, diffusion and corrosion

Summary

Introduction

When assessing nuclear power plant life, stress corrosion cracking (SCC) plays an important role. Due to the constant stresses applied, the oxide film ruptured, and new virgin material was exposed to be dissolved and repassivated This process was repeated, see Figure 1. The effect of cold work has been shown [24,25,26,27,28,29], and a goal was to predict the coupled effect from bTohthe enlevcitrrooncmheenmt aicnadl cmoloddweloarkt .the crack tip was set up with the slip-oxidation mode by Ford [4,30]. GWehmenattheeriTaSlL, was combined with the degradation model from Sedlak et al [22], the TSL acquired the capability to change from a ductile to a brittle material, which here was from the austenitic the one parameter dηstaTamin=alge1ses,−isntetTreomledtfaoufxTci(χtee∆sfdofmOxairxdt)eizparnodduPcatns.dTohlfei irreversibility was set up with [35].

Results

Yield Strength

Stress Intensity Factor