Comparison between SSF and Critical-Plane models to predict fatigue lives under multiaxial proportional load histories
Journal Title: Frattura ed Integrità Strutturale - Year 2016, Vol 10, Issue 38
Abstract
Materials can be classified as shear or tensile sensitive, depending on the main fatigue microcrack initiation process under multiaxial loadings. The nature of the initiating microcrack can be evaluated from a stress scale factor (SSF), which usually multiplies the hydrostatic or the normal stress term from the adopted multiaxial fatigue damage parameter. Low SSF values are associated with a shear-sensitive material, while a large SSF indicates that a tensile-based multiaxial fatigue damage model should be used instead. For tension-torsion histories, a recent published approach combines the shear and normal stress amplitudes using a SSF polynomial function that depends on the stress amplitude ratio (SAR) between the shear and the normal components. Alternatively, critical-plane models calculate damage on the plane where damage is maximized, adopting a SSF value that is assumed constant for a given material, sometimes varying with the fatigue life (in cycles), but not with the SAR, the stress amplitude level, or the loading path shape. In this work, in-phase proportional tension-torsion tests in 42CrMo4 steel specimens for several values of the SAR are presented. The SSF approach is then compared with critical-plane models, based on their predicted fatigue lives and the observed values for these tension-torsion histories
Authors and Affiliations
Manuel de Freitas, Luis Reis , Marco Meggiolaro, Jaime Pinho de Castro
Keywords
Related Articles
- EP ID EP90976
- DOI 10.3221/IGF-ESIS.38.16
- Views 45
- Downloads 0
Hydrogen Re-Embrittlement of Aerospace grade High Strength Steels
Hydrogen Re-Embrittlement on anodically coated high strength steels is a relevant risk for aerospace structures due to the possibility of hydrogen uptake during the operative life of the components. AISI 4340...
Flaw-tolerance of nonlocal discrete systems and interpretationaccording to network theory
Discrete systems are modeled as a network of nodes (particles, molecules, or atoms) linked bynonlinear springs to simulate the action of van der Waals forces. Such systems are nonlocal if links connectingnon-adjace...
Effect of defect length on rolling contact fatigue crack propagation in high strength steel
The objective of the present paper is to clarify the effect of defect length in depth direction on rolling contact fatigue (RCF) crack propagation in high strength steel. RCF test and synchrotron radiation micro&n...
A coupled interface-body nonlocal damage model for the analysis of FRP strengthening detachment from cohesive material
In the present work, a new model of the FRP-concrete or masonry interface, which accounts for the coupling occurring between the degradation of the cohesive material and the FRP detachment, is presented; in particular, a...
Improvement of performance of ultra-high performance concrete based composite material added with nano materials
Ultra-high performance concrete (UHPC), a kind of composite material characterized by ultra high strength, high toughness and high durability. It has a wide application prospect in engineering practice. But t...