scholarly journals Numerical analysis for the thermal ageing effect on fracture behaviors of CF8A pipes and piping systems under monotonic and very low cycle fatigue loading conditions

2018 ◽  
Vol 13 ◽  
pp. 1305-1311
Author(s):  
Gyo Geun Youn ◽  
Hyun Suk Nam ◽  
Yun Jae Kim
Keyword(s):  
Numerical Analysis ◽  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
Thermal Ageing ◽  
Ageing Effect ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Fracture Behaviors ◽  
Piping Systems

A Multi-Level Low Cycle Fatigue Damage Model for Forging Die Material

2006 ◽  
Vol 514-516 ◽  
pp. 804-809
Author(s):  
S. Gao ◽  
Ewald Werner
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Die Material ◽  
Multi Level ◽  
Loading Sequence ◽  
Forging Die

The forging die material, a high strength steel designated W513 is considered in this paper. A fatigue damage model, based on thermodynamics and continuum damage mechanics, is constructed in which both the previous damage and the loading sequence are considered. The unknown material parameters in the model are identified from low cycle fatigue tests. Damage evolution under multi-level fatigue loading is investigated. The results show that the fatigue life is closely related to the loading sequence. The fatigue life of the materials with low fatigue loading first followed by high fatigue loading is longer than that for the reversed loading sequence.

Effects of Surface Finish and Loading Conditions on the Low Cycle Fatigue Behavior of Austenitic Stainless Steel in PWR Environment for Various Strain Amplitude Levels

2009 ◽  
Author(s):  
Jean Alain Le Duff ◽  
Andre´ Lefranc¸ois ◽  
Jean Philippe Vernot
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Amplitude ◽  
Surface Finish ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Complex Loading ◽  
Loading Conditions ◽  
Test Results ◽  
Cycle Fatigue

In February/March 2007, The NRC issued Regulatory Guide “RG1.207” and Argonne National Laboratory issued NUREG/CR-6909 that is now applicable in the US for evaluations of PWR environmental effects in fatigue analyses of new reactor components. In order to assess the conservativeness of the application of this NUREG report, Low Cycle Fatigue (LCF) tests were performed by AREVA NP on austenitic stainless steel specimens in a PWR environment. The selected material exhibits in air environment a fatigue behavior consistent with the ANL reference “air” mean curve, as published in NUREG/CR-6909. LCF tests in a PWR environment were performed at various strain amplitude levels (± 0.6% or ± 0.3%) for two loading conditions corresponding to a simple or to a complex strain rate history. The simple loading condition is a fully reverse triangle signal (for comparison purposes with tests performed by other laboratories with the same loading conditions) and the complex signal simulates the strain variation for an actual typical PWR thermal transient. In addition, two various surface finish conditions were tested: polished and ground. This paper presents the comparisons of penalty factors, as observed experimentally, with penalty factors evaluated using ANL formulations (considering the strain integral method for complex loading), and on the other, the comparison of the actual fatigue life of the specimen with the fatigue life predicted through the NUREG report application. For the two strain amplitudes of ± 0.6% and ± 0.3%, LCF tests results obtained on austenitic stainless steel specimens in PWR environment with triangle waveforms at constant low strain rates give “Fen” penalty factors close to those estimated using the ANL formulation (NUREG/6909). However, for the lower strain amplitude level and a triangle loading signal, the ANL formulation is pessimistic compared to the AREVA NP test results obtained for polished specimens. Finally, it was observed that constant amplitude LCF test results obtained on ground specimens under complex loading simulating an actual sequence of a cold and hot thermal shock exhibits lower combined environmental and surface finish effects when compared to the penalty factors estimated on the basis of the ANL formulations. It appears that the application of the NUREG/CR-6909 in conjunction with the Fen model proposed by ANL for austenitic stainless steel provides excessive margins, whereas the current ASME approach seems sufficient to cover significant environmental effects for representative loadings and surface finish conditions of reactor components.

Deformation Mechanisms of CoCrFeMnNi High-Entropy Alloy Under Low-Cycle-Fatigue Loading

2021 ◽  
Author(s):  
Kaiju Lu ◽  
Ankur Chauhan ◽  
Aditya Srinivasan Tirunilai ◽  
Jens Freudenberger ◽  
Alexander Kauffmann ◽  
...  
Keyword(s):  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
Deformation Mechanisms ◽  
High Entropy Alloy ◽  
Cycle Fatigue ◽  
High Entropy

Low Cycle Fatigue of Unidirectional Glass/Epoxy Composites

1999 ◽  
Author(s):  
V. M. Harik ◽  
J. R. Klinger ◽  
B. K. Fink ◽  
T. A. Bogetti ◽  
A. Paesano ◽  
...  
Keyword(s):  
Polymer Matrix Composites ◽  
Low Cycle Fatigue ◽  
Glass Fibers ◽  
Fatigue Loading ◽  
Large Strains ◽  
Matrix Composites ◽  
Cycle Fatigue ◽  
Degradation Rates ◽  
Characteristics Analysis ◽  
Stress Ratios

Abstract Low cycle fatigue (LCF) behavior of unidirectional polymer matrix composites (PMCs) reinforced with glass fibers is investigated. LCF conditions involve high loads reaching up to 90% of the material ultimate strength. LCF characterization of PMCs is carried out under tension-tension fatigue loading to identify the key physical phenomena occurring in PMCs under LCF conditions and to determine their unique characteristics. Analysis of experimental data indicates that finite strain rates, large strains and stress ratios may affect LCF behavior of PMC structures and the property degradation rates.

Sign in / Sign up

Export Citation Format

Share Document