Crack Tip Damage Mechanism under Monotonic and Cyclic Loading Conditions

2009 ◽  
Vol 417-418 ◽  
pp. 105-108
Author(s):  
Himadri Roy ◽  
S. Sivaprasad ◽  
S. Tarafder ◽  
Kalyan Kumar Ray
Keyword(s):  
Stainless Steel ◽  
Cyclic Loading ◽  
Fracture Resistance ◽  
Compressive Load ◽  
Crack Tip ◽  
Damage Mechanism ◽  
J Integral ◽  
Loading Conditions ◽  
R Ratio ◽  
304Ln Stainless Steel

Fracture resistance of AISI 304LN stainless steel has been examined by monotonic and cyclic J-integral tests, the latter being carried out using periodic unloading as per pre-determined R-ratio. The cyclic fracture resistance is found to be almost 1/5th of its corresponding monotonic value. The deterioration of fracture resistance under cyclic loading has been attributed to crack tip resharpening due to smearing and smashing of voids owing to rubbing of adjacent crack surfaces in the compressive load cycles.

High-cycle and very-high-cycle fatigue behavior of a stainless steel for air-conditioning compressor valve plates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xu Jia ◽  
Yang Ou Xiang ◽  
Hu Yuan Pei ◽  
Song Wei
Keyword(s):  
Stainless Steel ◽  
Cyclic Loading ◽  
Air Conditioning ◽  
High Cycle Fatigue ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Content Type ◽  
Very High Cycle Fatigue ◽  
Load Characteristics ◽  
Very High

PurposeThe investigations could guide the structural design and fatigue life prediction of air-conditioning compressor valve plates.Design/methodology/approachThe High-Cycle Fatigue (HCF) and Very-High-Cycle Fatigue (VHCF) behaviors of stainless steel used for air-conditioning compressor valve plates were investigated. Monotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure.FindingsThe crack initiation can be observed as the arc-shaped cracks at both sides of specimens and Y-shaped crack bifurcation in the specimens. Moreover, the middle section and the cracks at both ends are not connected to the surface of the specimen. The stress-life results of the materials under two directions (vertical and horizontal) were provided to examine the difference in fatigue strength.Originality/valueMonotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure. Based on the experimental data, the results indicate that specimens under cyclic loading conditions could demonstrate better mechanical performance than static loadings.

Controlled Initiation of Short Fatigue Cracks in 316L Steel

2005 ◽  
Author(s):  
D. Stefanescu ◽  
J. Marrow ◽  
M. Preuss ◽  
A. Sherry
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
Crack Opening Displacement ◽  
Crack Nucleation ◽  
Fatigue Cracks ◽  
Crack Opening ◽  
Crack Tip ◽  
Image Correlation ◽  
Opening Displacement ◽  
R Ratio

Validation of models for short crack behavior requires accurate measurement of crack opening displacement and crack tip strain fields. Development of reliable measurement procedures, using new techniques such as Image Correlation (IC), requires specimens containing cracks with a well defined geometry. In this paper, results of an experimental study concerning controlled initiation of short fatigue cracks at positive R-ratio in laboratory specimens made from 316L stainless steel are presented. Experimental techniques, including hardness testing and X-ray diffraction were employed in order to investigate the effect of surface preparation on the surface mechanical properties and residual stresses. Crack nucleation is difficult in smooth specimens of 316L austenitic stainless steel at positive R-ratio due to the high fatigue limit and low tensile strength. Specimens with a thin ligament were therefore developed to enable nucleation of a single short fatigue crack. An experimental study of the crack growth aspect ratio evolution was then carried out using a beach marking technique. The technique described in this paper enables single short fatigue cracks of well defined geometry to be nucleated under tensile cyclic loading. Stress corrosion cracks can be developed using the same specimen geometry. Miniature tensile specimens can then be extracted to perform in-situ measurements of the crack opening displacement and crack tip strain field by Image Correlation from Scanning Electron Microscopy observations.

A Comparison of Two Self-Consistent Models to Predict the Cyclic Behavior of Polycrystals

2004 ◽  
Vol 126 (1) ◽  
pp. 62-69 ◽  
Author(s):  
A. Abdul-Latif
Keyword(s):  
Stainless Steel ◽  
Cyclic Loading ◽  
316L Stainless Steel ◽  
Kinematic Hardening ◽  
Cyclic Behavior ◽  
Loading Conditions ◽  
Local Responses ◽  
Self Consistent ◽  
Interaction Law ◽  
Local Levels

Being of particular interest in this work, the effect of the interaction law on the predicted non-linear overall and local behaviors of FCC polycrystals of two well-established self-consistent models is examined under uni, bi, and triaxial cyclic loading conditions. The principal difference between these models is related to their interaction laws. Comparisons between the predictions of the models are performed at the overall and local levels simultaneously. Some experimental cyclic results of two states of Waspaloy and 316L stainless steel are employed in calibrating the parameters of both models. The effects of loading complexity, aggregate type and the kinematic hardening on the polycrystal responses are investigated for each model. It is recognized that the connection between the aggregate constitution and the form of the loading paths play also an important role notably on the local responses of polycrystals.

J-R Fracture Toughness of Nuclear Piping Materials Under Excessive Seismic Loading Condition

2016 ◽  
Author(s):  
Jin Weon Kim ◽  
Myung Rak Choi ◽  
Sang Bong Lee ◽  
Yun Jae Kim
Keyword(s):  
Fracture Toughness ◽  
Cyclic Loading ◽  
Fracture Resistance ◽  
Cyclic Load ◽  
Fracture Behavior ◽  
Loading Rate ◽  
Seismic Loading ◽  
Monotonic Loading ◽  
Rate Effect ◽  
Loading Conditions

This study investigated the loading rate effect on the fracture resistance under cyclic loading conditions to clearly understand the fracture behavior of piping materials under excessive seismic conditions. J-R fracture toughness tests were conducted under monotonic and cyclic loading conditions at various displacement rates at room temperature (RT) and the operating temperature of nuclear power plants (NPPs), i.e., 316°C. SA508 Gr. 1a lo w-alloy steel (LAS) and SA312 TP316 stainless steel (SS) piping materials were used for the tests. The fracture resistance under a reversible cyclic load was considerably lower than that under monotonic load regardless of test temperature, material, and loading rate. Under both cyclic and monotonic loading conditions, the fracture behavior of SA312 TP316 SS was independent of the loading rate at both RT and 316°C. For SA508 Gr. 1a LAS, the loading rate effect on the fracture behavior was appreciable at 316°C under both cyclic and monotonic loading conditions. However, the loading rate effect diminished when the cyclic load ratio (R) was −1. Thus, it was recognized that the fracture behavior of piping materials, including seismic loading characteristics, can be evaluated when tested under a cyclic load of R = −1 at a quasi-static loading rate.

The Effect of T-Stress on Crack-Tip Plastic Zones Under Cyclic Mixed-Mode Loading Conditions

2013 ◽  
Author(s):  
Qays Nazarali ◽  
Xin Wang
Keyword(s):  
Stress Intensity ◽  
Cyclic Loading ◽  
Stress Field ◽  
Plastic Zone ◽  
Mixed Mode ◽  
Crack Tip ◽  
Mode I ◽  
Loading Conditions ◽  
T Stress ◽  
Plastic Zones

In this paper, the influence of T-stress on crack-tip plastic zones under mixed-mode I and II loading conditions under cyclic loading is examined. The crack-tip stress field is defined in terms of the ranges of mixed-mode stress intensity factors and the T-stress using William’s series expansion. The crack-tip stress field is incorporated into the Von Mises yield criteria to develop an expression that determines the cyclic crack-tip plastic zone. Using the resultant expression, the cyclic plastic zone is obtained for various combinations of mode II to mode I stress intensity factor ratios and levels of T-stress. For the purpose of demonstrating the significance of the T-stress, this paper further analyses the plastic zone size for center cracked plate (CCP) specimen subjected to bi-axial mixed-mode cyclic loading.

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