Low Cycle Fatigue Behavior of Zirconium Tube under the Cyclic Pressurization

2007 ◽  
Vol 345-346 ◽  
pp. 271-274 ◽  
Author(s):  
Jun Hwan Kim ◽  
Myoung Ho Lee ◽  
Byoung Kwon Choi ◽  
Yong Hwan Jeong
Keyword(s):  
Fatigue Limit ◽  
Fatigue Test ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Creep Fatigue ◽  
Zirconium Tube ◽  
Fractographic Observation

Study was attempted to produce stress-life curve of the zirconium tube under the cyclic pressurization and to analyze its behavior. The internal pressurization machine was devised and the low cycle fatigue test at the zirconium cladding tube was carried out. The result showed that the O’Donnell and Langer relationship can be fitted to the fatigue behavior of the zirconium cladding under the cyclic pressurization, where the fatigue limit of the Zircaloy-4 at 350oC was shown at 341.6MPa. From the analysis of the diametral changes and the fractographic observation, a combined creep-fatigue interaction rather than a pure fatigue had an influence on the failure of the zirconium cladding under the cyclic pressurization at 350oC.

Component Low Cycle Fatigue Behavior Based on Standard Calculation Procedure and Non-Linear FEA

2017 ◽  
Author(s):  
Jürgen Rudolph ◽  
Adrian Willuweit ◽  
Steffen Bergholz ◽  
Christian Philippek ◽  
Jevgenij Kobzarev
Keyword(s):  
Power Plants ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Hybrid Approach ◽  
Combined Cycle ◽  
Cycle Fatigue ◽  
Element Analysis ◽  
Constitutive Material Model ◽  
Standard Design ◽  
Creep Fatigue

Components of conventional power plants are subject to potential damage mechanisms such as creep, fatigue and their combination. These mechanisms have to be considered in the mechanical design process. Against this general background — as an example — the paper focusses on the low cycle fatigue behavior of a main steam shut off valve. The first design check based on standard design rules and linear Finite Element Analysis (FEA) identifies fatigue sensitive locations and potentially high fatigue usage. This will often occur in the context of flexible operational modes of combined cycle power plants which are a characteristic of the current demands of energy supply. In such a case a margin analysis constitutes a logical second step. It may comprise the identification of a more realistic description of the real operational loads and load-time histories and a refinement of the (creep-) fatigue assessment methods. This constitutes the basis of an advanced component design and assessment. In this work, nonlinear FEA is applied based on a nonlinear kinematic constitutive material model, in order to simulate the thermo-mechanical behavior of the high-Cr steel component mentioned above. The required material parameters are identified based on data of the accessible reference literature and data from an own test series. The accompanying testing campaign was successfully concluded by a series of uniaxial thermo-mechanical fatigue (TMF) tests simulating the most critical load case of the component. This detailed and hybrid approach proved to be appropriate for ensuring the required lifetime period of the component.

The Effect of Nitrogen Alloying on the Low Cycle Fatigue and Creep-Fatigue Interaction Behavior of 316LN Stainless Steel

2013 ◽  
Vol 794 ◽  
pp. 441-448 ◽  
Author(s):  
G.V. Prasad Reddy ◽  
R. Sandhya ◽  
M.D. Mathew ◽  
S. Sankaran
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Hold Time ◽  
Cyclic Plasticity ◽  
Dynamic Strain ◽  
Cycle Fatigue ◽  
Intergranular Cracking ◽  
Creep Fatigue

Low cycle fatigue (LCF) and Creep-fatigue interaction (CFI) behavior of 316LN austenitic stainless steel alloyed with 0.07, 0.11, 0.14, .22 wt.% nitrogen is briefly discussed in this paper. The strain-life fatigue behavior of these steels is found to be dictated by not only cyclic plasticity but also by dynamic strain aging (DSA) and secondary cyclic hardening (SCH). The influence of the above phenomenon on cyclic stress response and fatigue life is evaluated in the present study. The above mentioned steels exhibited both single-and dual-slope strain-life fatigue behavior depending on the test temperatures. Concomitant dislocation substructural evolution has revealed transition in substructures from planar to cell structures justifying the change in slope. The beneficial effect of nitrogen on LCF life is observed to be maximum for 316LN with nitrogen in the range 0.11 - 0.14 wt.%, for the tests conducted over a range of temperatures (773-873 K) and at ±0.4 and 0.6 % strain amplitudes at a strain rate of 3*10-3 s-1. A decrease in the applied strain rate from 3*10-3 s-1 to 3*10-5 s-1 or increase in the test temperature from 773 to 873 K led to a peak in the LCF life at a nitrogen content of 0.07 wt.%. Similar results are obtained in CFI tests conducted with tensile hold periods of 13 and 30 minutes. Fractography studies of low strain rate and hold time tested specimens revealed extensive intergranular cracking.

Low cycle fatigue and creep-fatigue behavior of Ni-based alloy 230 at 850 °C

2013 ◽  
Vol 563 ◽  
pp. 152-162 ◽  
Author(s):  
Xiang Chen ◽  
Zhiqing Yang ◽  
Mikhail A. Sokolov ◽  
Donald L. Erdman ◽  
Kun Mo ◽  
...  
Keyword(s):  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Creep Fatigue

An Evaluation of Fatigue Damage in Low-Cycle Range for Sn-3.5Ag, Sn-0.7Cu Lead-Free Solders and Sn-Pb Eutectic Solder Using Image Processing to Surface Feature

2005 ◽  
Author(s):  
Takehiko Takahashi ◽  
Susumu Hioki ◽  
Ikuo Shohji ◽  
Osamu Kamiya
Keyword(s):  
Image Processing ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Surface Deformation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Lead Free ◽  
Cycle Fatigue ◽  
Surface Features ◽  
Lead Free Solders

The low-cycle fatigue behavior of Sn-3.5mass%Ag, Sn-0.7mass%Cu lead-free solders and Sn-37mass%Pb solder were investigated at strain rate of 0.1%/s with a non-contact extensometer at room temperature (22 ± 3 °C). In addition, the relationship between the surface features in the low-cycle fatigue test and the fatigue life of those solders were investigated by image processing. The fatigue lives of Sn-3.5mass%Ag and Sn-0.7mass%Cu were better than that of Sn-37mass%Pb. The low-cycle fatigue behavior on each solder followed Coffin-Manson equation. The surface deformation in fine wrinkles was observed in the low-cycle fatigue test at each solder. The surface features for each solder were evaluated by image processing from the surface deformation. The surface features in the low-cycle fatigue test did not appear until under 10% of the fatigue life for Sn-3.5mass%Ag, until 10% of the fatigue life for Sn-0.7mass%Cu, and until 20% of the fatigue life for Sn-37mass%Pb.

Low Cycle Fatigue and Creep-Fatigue Behavior of Alloy 617 at High Temperature

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Celine Cabet ◽  
Laura Carroll ◽  
Richard Wright
Keyword(s):  
High Temperature ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Dominant Role ◽  
Hold Time ◽  
Outlet Temperature ◽  
Cycle Fatigue ◽  
Alloy 617 ◽  
Creep Fatigue

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the very high temperature nuclear reactor (VHTR), expected to have an outlet temperature as high as 950 °C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanisms and failure life. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950 °C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle fatigue specimens exhibited transgranular cracking. Intergranular cracking was observed in the creep-fatigue specimens and the addition of a hold time at peak tensile strain degraded the cycle life. This suggests that creep-fatigue interaction occurs and that the environment may be partially responsible for accelerating failure.

The Influence of Dwell Time on Low Cycle Fatigue Behavior of Ni-base Superalloy IC10

2017 ◽  
Vol 36 (8) ◽  
pp. 795-803
Author(s):  
Anqiang Wang ◽  
Lu Liu ◽  
Zhixun Wen ◽  
Zhenwei Li ◽  
Zhufeng Yue
Keyword(s):  
Fatigue Life ◽  
Dwell Time ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Dislocation Line ◽  
Reverse Direction ◽  
Structure Evolution ◽  
Cycle Fatigue ◽  
Creep Fatigue ◽  
Base Superalloy

AbstractLow cycle fatigue and creep-fatigue experiments of IC10 Ni-base superalloy plate specimens with multiple holes were performed below 1,000 °C. The average fatigue life is 105.4 cycles, while the creep-fatigue life is 103.4 cycles, which shows that the life of creep-fatigue is reduced 1–2 times compared with low cycle fatigue life. After tests, the detailed fracture and microscopic structure evolution were observed by scanning electron microscopy (SEM); meanwhile, the constitutive model based on crystal plasticity theory was established and the fracture mechanism was analyzed. Three conclusions have been obtained: First, the load during dwell time leads to the damage accumulation caused by deformation and the interaction of fatigue and creep shortens the service life of materials seriously. Second, in order to maintain the macroscopic deformation, a new slip plane starts to makes the dislocation slide in reverse direction, which leads to fatigue damage and initial cracks. Third, the inner free surface creates opportunities for escape of the dislocation line, which is caused by the cavity. What’s more, the cure dislocation generated by cyclic loading contributes to the formation and growth of cavities.

Fatigue Behavior of K447A Superalloy under Low Cycle Fatigue and Creep-Fatigue Interaction Conditions

2015 ◽  
Vol 750 ◽  
pp. 121-126 ◽  
Author(s):  
Hui Chen Yu ◽  
Cheng Li Dong ◽  
Ying Li
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Hold Time ◽  
Strain Ratio ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Creep Fatigue ◽  
Cyclic Damage ◽  
Mean Stresses

Strain-controlled low cycle fatigue (LCF) and creep-fatigue interaction (CFI) tests of K447A are conducted at 760oC in order to investigate the effects of different dwell times and strain ratios on the fatigue behavior and life. For the cases of stain ratio Rε=-1 with balanced hold time, the tensile and compressive mean stresses will generate. For the case of stain ratio Rε=-1 with compressive holding 60s, the tensile mean stress will produce. For the case of stain ratio Rε=-1 with tensile holding 60s, the compressive mean stress will produce. For the cases of stain ratio Rε=0.1 and Rε=-1with no hold time, the tensile mean stress will produce. The cyclic damage accumulation (CDA) method and modified CDA method were employed to predict the fatigue life for K447A, respectively. The fatigue life predicted by CDA method is within the scatter band of 18.2X. The fatigue life predicted by the modified CDA method agrees very well with the experimental life and the predicted life is well within the scatter band of 3.1X, which means that the modified CDA method is able to consider the influences of dwell time and strain ratio on the fatigue life of K447A.

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