Development of a model for the prediction of the fretting fatigue regimes

2001 ◽  
Vol 16 (9) ◽  
pp. 2716-2723 ◽  
Author(s):  
T. E. Matikas ◽  
P. D. Nicolaou
Keyword(s):  
Fatigue Life ◽  
Research Effort ◽  
Fretting Fatigue ◽  
Partial Slip ◽  
Geometrical Parameters ◽  
Metallic Materials ◽  
Stick Slip ◽  
Contact Conditions ◽  
Contact Materials ◽  
Fatigue Life Reduction

parameters that govern the life of metallic materials under conditions of fretting fatigue may be divided into two broad categories. The first category concerns the material properties (e.g., yield strength, elastic modulus, and surface roughness) while the second concerns the externally imposed loading conditions and contact geometry. The two in-contact materials may either stick, slip, or stick-slip (i.e., there is a slip and a stick region on their interface) against each other. It has been shown that the fatigue life reduction is highest under partial slip. The objective of the present research effort is to develop a model that enables the prediction of the particular fretting fatigue regime (i.e., slip, stick, or mixed). The parameters that affect the fretting fatigue life of metallic components were identified and integrated into a model, which allows the prediction of the interfacial contact conditions. The model was first used to identify the sensitivity of the fretting fatigue regimes upon the materials and external, and geometrical parameters. Experimental results concerned with the fatigue life were plotted on the fretting maps; the fretting fatigue regimes indicated by the latter enabled the interpretation of the experimental data.

Elastic-Plastic Contact Conditions for Frictionally Constrained Bodies Under Cyclic Tangential Loading

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
V. Chaudhry ◽  
Satish V. Kailas
Keyword(s):  
Stainless Steel ◽  
Experimental Studies ◽  
Partial Slip ◽  
Tangential Displacement ◽  
Damage Mode ◽  
Contact Interface ◽  
Stick Slip ◽  
Contact Conditions ◽  
Elastic Plastic ◽  
Constrained Conditions

A Frictionally constrained condition implies dependence of friction force on tangential displacement amplitude. The condition may occur due to chemical, physical, and/or mechanical interaction between the contacting surfaces. The condition, sometimes also referred to as the presliding condition or partial slip condition, is characterized under fretting. Under such conditions, various experimental studies indicate the existence of two distinguishable regions, that is, stick region and slip region. In the present study, frictionally constrained conditions are identified and the evolutions of stick-slip regions are investigated in detail. Investigations have been performed on self-mated stainless steel and chromium carbide coated surfaces mated against stainless steel, under both vacuum and ambient conditions. Contact conditions prevailing at the contact interface were identified based on the mechanical responses and were correlated with the surface damage observed. Surface degradation has been observed in the form of microcracks and material transfer. Detailed numerical analysis has also been performed in order to understand the energy dissipation and the damage mode involved in the surface or subsurface damage. It has been observed that under frictionally constrained conditions, the occurrence of annular slip features are mainly due to the junction growth, resulting from elastic-plastic deformation at the contact interface. Ratcheting has been observed as the governing damage mode under cyclic tangential loading condition.

scholarly journals Characterization of Austenitic Stainless Steels with Regard to Environmentally Assisted Fatigue in Simulated Light Water Reactor Conditions

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 307
Author(s):  
Matthias Bruchhausen ◽  
Gintautas Dundulis ◽  
Alec McLennan ◽  
Sergio Arrieta ◽  
Tim Austin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Fatigue Life ◽  
Elevated Temperature ◽  
Strain Rate ◽  
Power Plants ◽  
Research Effort ◽  
Hold Time ◽  
Strain Range ◽  
Austenitic Steels ◽  
Mean Strain

A substantial amount of research effort has been applied to the field of environmentally assisted fatigue (EAF) due to the requirement to account for the EAF behaviour of metals for existing and new build nuclear power plants. We present the results of the European project INcreasing Safety in NPPs by Covering Gaps in Environmental Fatigue Assessment (INCEFA-PLUS), during which the sensitivities of strain range, environment, surface roughness, mean strain and hold times, as well as their interactions on the fatigue life of austenitic steels has been characterized. The project included a test campaign, during which more than 250 fatigue tests were performed. The tests did not reveal a significant effect of mean strain or hold time on fatigue life. An empirical model describing the fatigue life as a function of strain rate, environment and surface roughness is developed. There is evidence for statistically significant interaction effects between surface roughness and the environment, as well as between surface roughness and strain range. However, their impact on fatigue life is so small that they are not practically relevant and can in most cases be neglected. Reducing the environmental impact on fatigue life by modifying the temperature or strain rate leads to an increase of the fatigue life in agreement with predictions based on NUREG/CR-6909. A limited sub-programme on the sensitivity of hold times at elevated temperature at zero force conditions and at elevated temperature did not show the beneficial effect on fatigue life found in another study.

scholarly journals Half-plane contacts subject to remote tension

2021 ◽  
pp. 030932472098844
Author(s):  
Nils Cwiekala ◽  
David A Hills
Keyword(s):  
Contact Problem ◽  
Half Plane ◽  
Asymptotic Form ◽  
Fretting Fatigue ◽  
The State ◽  
Partial Slip ◽  
Practical Relevance ◽  
Plane Contact ◽  
State Of Stress ◽  
Plane Contact Problem

The state of stress present in an elastic half-plane contact problem, where one or both bodies is subject to remote tension has been investigated, both for conditions of full stick and partial slip. The state of stress present near the contact edges is studied for different loading scenarios in an asymptotic form. This is of practical relevance to the study of contacts experiencing fretting fatigue, and enables the environment in which cracks nucleate to be specified.

Influence of Wear Properties on Fretting Fatigue Life of a CK45 Alloy and the Al7175 Alloy

2008 ◽  
Vol 587-588 ◽  
pp. 971-975 ◽  
Author(s):  
M. Buciumeanu ◽  
A.S. Miranda ◽  
F.S. Silva
Keyword(s):  
Wear Resistance ◽  
Fatigue Life ◽  
Material Properties ◽  
Fatigue Behavior ◽  
Synergetic Effect ◽  
Fretting Fatigue ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Wear Properties

The main objective of this work was to study the influence of the wear properties of two commercial alloys (CK45 and Al7175) on their fretting fatigue behavior. It is verified the effect of material local degradation by wear on a fatigue strength reduction factor, namely the stress concentration factor, and on the overall fretting fatigue life of these materials. The fretting fatigue phenomenon is a synergetic effect between wear and fatigue. It is dependent on both the fatigue and the wear properties of the materials. Material properties promoting an increase in wear resistance should enhance fretting fatigue life.

Probabilistic fretting fatigue life prediction of Ti–6Al–4V

2010 ◽  
Vol 32 (12) ◽  
pp. 1937-1947 ◽  
Author(s):  
Patrick J. Golden ◽  
Harry R. Millwater ◽  
Xiaobin Yang
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Fretting Fatigue ◽  
Fatigue Life Prediction

scholarly journals Influence of Material Ductility on Fatigue Life under Multiaxial Proportional and Non-Proportional Normal and Shear Stresses

2019 ◽  
Vol 300 ◽  
pp. 17001 ◽  
Author(s):  
Cetin Morris Sonsino
Keyword(s):  
Fatigue Life ◽  
Tensile Elongation ◽  
Shear Stresses ◽  
Normal Strain ◽  
Proportional Loading ◽  
Ductile Materials ◽  
Critical Components ◽  
Material Ductility ◽  
Fatigue Life Reduction ◽  
Normal And Shear Stresses

Current experiences show that a non-proportional loading of ductile materials such as wrought steels, wrought aluminium or magnesium alloys, not welded or welded, causes a significant fatigue life reduction under an out-of-phase shear strain or shear stress superimposed on a normal strain or normal stress compared with proportional in-phase loading. However, when ductility, here characterised by tensile elongation, is reduced by a heat treatment or by another manufacturing technology such as casting or sintering, the afore-mentioned life reduction is compensated or even inversed, i. e. longer fatigue life results compared with proportional loading. Some actual results, determined with additive manufactured titanium, suggest that microstructural features such as manufacturing-dependent internal defects like microporosities should be considered in addition to the ductility level. This complex life behaviour under non-proportional loading cannot always be estimated. Therefore, in experimental proofs of multiaxial loaded parts, especially safety-critical components or structures, with real or service-like signals, emphasis must be placed on retaining non-proportionalities between loads and stresses/strains, respectively.

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