3D thickness effects around notch and crack tip stress/strain fields
Journal Title: Frattura ed Integrità Strutturale - Year 2015, Vol 9, Issue 33
Abstract
Notches and cracks are usually approximately modeled as two-dimensional problems using solutions from plane elasticity to quantify localized stress/strain concentration effects around their tips. However, they may be associated with high gradients that can severely restrict local Poisson-induced transversal strains and cause important 3D stress fields around those tips. Fatigue crack initiation and growth, plastic zone sizes and shapes, and localized constraint effects that affect toughness are typical problems associated with such 3D effects, which may lead to non-conservative damage and life predictions if neglected. To quantify how important they can be, first finite element techniques are used to simulate thickness and notch-tip radius effects in the fields around such tips, and to evaluate their importance from the structural design point of view. Then, versatile sub-modeling techniques are used to study similar effects along the fronts of short and long cracks, and a stepwise re-meshing routine is used to show how an initially straight crack must slightly curve its front during its propagation by fatigue, due to the unavoidable 3D effects that always surround real crack tips.
Authors and Affiliations
R. Góes, J. Castro, M. Meggiolaro
Keywords
Related Articles
- EP ID EP100599
- DOI 10.3221/IGF-ESIS.33.12
- Views 83
- Downloads 0
Methodological developments in the field of structural integrity analyses of large scale reactor pressure vessels in Hungary
Buildings, structures and systems of large scale and high value (e.g. conventional and nuclear power plants, etc.) are designed for a certain, limited service lifetime. If the standards and guidelines of the time...
Plastic flow equations for the local strain approach in the multiaxial case
This paper presents a system of plastic flow equations which uses and generalizes to the multiaxial case a number of concepts commonly employed in the so-called Local Strain Approach to low cycle fatigue. Eve...
Analysis on the growth of different shapes of mineral microcracks in microwave field
Microwave heating-assisted ore grinding and crushing can effectively increase the dissociation energy of minerals and decrease energy consumption. Microcrack growth and distribution characteristics inside dif...
Crack path simulation for cylindrical contact under fretting conditions
In this work different strategies to estimate crack path for cylindrical contacts under fretting conditions are carried out. The main goal is to propose and to evaluate methodologies not only to estimate the ...
Experimental evaluation of plasticity-induced crack shielding from crack tip displacements fields
In this work it is proposed a methodology for the evaluation of plasticity-induced crack shielding from the analysis of the crack tip displacements fields measured by digital image correlation. This methodology i...