A New Fatigue Life Calculation Method Based on Non-Linear Cumulative Damage Theory

2013 ◽  
Vol 423-426 ◽  
pp. 2116-2122
Author(s):  
Fu Hai Cai ◽  
Xin Wang ◽  
Fu Ling Zhao
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Low Cycle Fatigue ◽  
Cumulative Damage ◽  
Operating Conditions ◽  
Cycle Fatigue ◽  
Operating Characteristics ◽  
Non Linear ◽  
Damage Theory ◽  
Boom Crane

Operating characteristics of small and medium tonnage lattice boom crane which withstand fatigue loads was analyzed in this paper. It showed that the lattice boom crane utilization level is in the overlap zone of low cycle fatigue and high cycle fatigue. There may be some plastic deformation in the structure. So the total damage calculated by the Palmgren-Miner rule had a large scatter. Typical operating conditions was analyzed that K-type welded joints of the boom is under axial load and in-plane bending loads. Several critical areas of K-type welded joints were determined by ANSYS finite element calculation software where the stress amplitude was larger on the single side of the lattice boom. A new stress spectrum acquisition method based on the “measured+statistics+compare+simulation” integrated strategy of crane K-type welded joints was proposed. Based on a simplified Huffman non-linear cumulative damage theory, fatigue life of crane K-type welded Joints were calculated based on the strain parameters. They were compared with Palmgren-Miner rule and together with fracture mechanics method. Results showed that although they were all conservative compared with test results, the new method can be applied easily in for engineering applications because it only need amplitude constant amplitude fatigue strain-life data.

scholarly journals Fatigue Life Analysis of Crane K-Type Welded Joints Based on Non-Linear Cumulative Damage Theory

2014 ◽  
Vol 60 (2) ◽  
pp. 135-144
Author(s):  
Cai Fuhai ◽  
Wang Xin ◽  
Liu Jiquan ◽  
Zhao Fuling
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Cumulative Damage ◽  
Non Linear ◽  
Damage Theory ◽  
Life Analysis ◽  
Fatigue Life Analysis

scholarly journals Low-cycle fatigue behaviour of laser welded high-strength steel DOMEX 700 MC

2018 ◽  
Vol 157 ◽  
pp. 05013 ◽  
Author(s):  
Peter Kopas ◽  
Milan Sága ◽  
František Nový ◽  
Bohuš Leitner
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
High Strength Steel ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Fatigue Life Analysis

The article presents the results of research on low cycle fatigue strength of laser welded joints vs. non-welded material of high-strength steel DOMEX 700 MC. The tests were performed under load controlled using the total strain amplitude ɛac. The operating principle of the special electro-mechanic fatigue testing equipment with a suitable clamping system was working on 35 Hz frequency. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue parameters. Studies have shown differences in the fatigue life of original specimens and laser welded joints analysed, where laser welded joints showed lower fatigue resistance. In this article a numerical analysis of stresses generated in bending fatigue specimens has been performed employing the commercially available FEM-program ADINA.

3D Crack Growth Analysis and Its Correlation With Experiments for Critical Turbine Components Under an International Collaborative Program

2008 ◽  
Author(s):  
J. Hou ◽  
J. Dubke ◽  
K. Barlow ◽  
S. Slater ◽  
L. Harris ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
Operating Conditions ◽  
Cycle Fatigue ◽  
3D Crack Growth ◽  
International Collaborative ◽  
2D And 3D ◽  
Growth Analyses ◽  
Stress Analyses

Following a reanalysis of the original material data plus supplementary Low Cycle Fatigue (LCF) specimen testing, an Original Equipment Manufacturer (OEM) reduced the low cycle fatigue life limits for a number of turbine components. To ascertain the validity of the new life limits, an international collaborative spin rig test program was initiated to provide more accurate low cycle fatigue life limits. The program covered a broad range of activities including, Finite Element (FE) stress analyses, cyclic spin rig testing, fractographic assessment and fatigue crack growth (FCG) analyses. This paper describes the 2D and 3D crack growth analyses of critical turbine components in a turboprop gas turbine engine, comparison of predicted results obtained using different software and also correlations with spin test results from the program. First, FE stress analyses of selected turbine components were carried out under both engine operating conditions and spin-rig test configurations in order to determine the maximum and minimum operating speeds required to match the stress ranges at the critical location specified by the OEM under engine operating conditions. Second, 2D and 3D crack growth analyses were performed independently by three organisations for a disk bolthole using the state-of-the-art software. Third, the predictions from different software were compared, and the relative technical merits of each software were evaluated. Finally, the predicted results were correlated against the striation counts determined by the OEM from the results of spin rig tests.

Cumulative Damage and Effect of Mean Strain in Low-Cycle Fatigue of a 2024-T351 Aluminum Alloy

1966 ◽  
Vol 88 (4) ◽  
pp. 801-810 ◽  
Author(s):  
Kiyotsugu Ohji ◽  
W. R. Miller ◽  
Joseph Marin
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Cumulative Damage ◽  
Strain Condition ◽  
Cycle Fatigue ◽  
History Of ◽  
Mean Strain ◽  
Strain Cycling ◽  
Cycling Behavior

By assuming a linear cumulative damage hypothesis for strain cycling, theories are developed in this paper for fatigue life under varying strain amplitude, residual ductility after a given history of strain cyling, and life under mean strain condition. These predictions are based on uniaxial completely reversed cycling behavior. The expressions obtained were compared with the experimental results on 2024-T351 aluminum alloy as well as other data available in the literature. The agreements between theories and experiments were found to be satisfactory.

Low-Cycle Fatigue Test of Circular Concrete Filled Tubular Columns

2008 ◽  
Vol 400-402 ◽  
pp. 873-880 ◽  
Author(s):  
Guo Wei Zhang ◽  
Yan Xiao ◽  
Sashi K. Kunnath
Keyword(s):  
Fatigue Life ◽  
Large Scale ◽  
Low Cycle Fatigue ◽  
Plastic Hinge ◽  
Cumulative Damage ◽  
Cycle Fatigue ◽  
Deformation And Failure ◽  
Tubular Columns ◽  
Critical Components ◽  
Reversed Deformation

During earthquake, the inelastic action in the plastic hinge regions of structures and bridges results in significant reversed deformation and failure of the critical components because of cumulative damage. To simulate seismic behavior of structure members and develop a simplicity damage criterion for circular concrete filled steel tubular (CFT) columns subjected to a series of earthquake excitations, an experimental study was undertaken to investigate the cumulative damage and relationship between low cycle fatigue life and displacement amplitude. Two types of large scale circular CFT columns with different kinds of seam weld and inner concrete compressive strength including nine specimens were tested under quasi static loading with constant and variable cyclic amplitudes. The test data were evaluated with the fatigue model relating deformation and fatigue life. Fatigue life expressions for application in damage-based seismic design are developed.

scholarly journals Fatigue Examination of HSLA Steel with Yield Strength of 960 MPa and Its Welded Joints under Strain Mode

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 228
Author(s):  
Tomasz Ślęzak
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Hsla Steel ◽  
Fatigue Crack Initiation ◽  
High Strength ◽  
Fusion Line ◽  
Cycle Fatigue ◽  
Strain Mode

The full benefits of application the high strength low alloyed steels HSLA can be achieved if the structures will be able to carry the alternate loads and fatigue cracks will not be formed, even in the vicinity of welded joints. For this reason the purpose of this study is to find and to explain the influence of different factors on fatigue crack initiation and the nature of crack propagation in HSLA steel and its welded joints. The S960QL steel and two types of welded joints were subjected to low cycle fatigue (LCF) tests at a strain mode and the received surfaces of fractures were analyzed using SEM microscope. Additionally, the microhardness measurements and the residual stress analyze in a cross-section of the joint were conducted. The maximum hardness was determined on the fusion line and more favorable hardness distribution was in the square joints than in single-V. Compiled maps of residual stresses have shown that the local orientation and values of the principal stress vector near the fusion line can influence negative the fatigue life. Finally, the square joints tested in the low cycle fatigue regime have shown a slightly higher fatigue life in comparison with single-V.

Fatigue Life and Stress Analysis of the Crankshaft of a Single Cylinder Diesel Engine under Variable Forces and Speeds

2021 ◽  
Vol 63 (8) ◽  
pp. 770-777
Author(s):  
Mehmet Bulut ◽  
Ömer Cihan ◽  
İlker Temizer
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Numerical Results ◽  
Operating Conditions ◽  
Cycle Fatigue ◽  
Failure Characteristics ◽  
Single Cylinder ◽  
Critical Regions ◽  
Sharp Corners ◽  
Ansys Workbench

Abstract In this paper, a single cylinder crankshaft manufactured with C45 steel was used to investigate variation in stress, deformation, and fatigue life and safety factor at critical locations of the crankshaft. For this purpose, numerical analyses using ANSYS/Workbench software were performed under different operating conditions. Additionally, low cycle fatigue analyses were conducted experimentally for the validation of the numerical results in terms of the failure characteristics of the crankshaft. It was concluded that chamfers at sharp corners of the crankshaft on the flywheel side showed critical regions, indicating that the experimental and numerical results were consistent. These results suggested that critical regions of the crankshaft could be optimized for the improvement of sustainability in long life service.

Quantification of Low-Cycle Fatigue Life for a Gas Turbine Compressor Vane Carrier Under Varying Operating Conditions

2021 ◽  
Author(s):  
Zixi Han ◽  
Zixian Jiang ◽  
Sophie Ehrt ◽  
Mian Li
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Low Cycle Fatigue ◽  
Operating Conditions ◽  
Cycle Fatigue ◽  
Gas Turbine Compressor

Investigation of High Cycle and Low Cycle Fatigue Interaction on Fatigue Behavior of Welded Joints

2012 ◽  
Vol 217-219 ◽  
pp. 2101-2106
Author(s):  
Liang Chen Wu ◽  
Dong Po Wang
Keyword(s):  
Adverse Effect ◽  
Fatigue Life ◽  
Welded Joints ◽  
High Frequency ◽  
Stress Ratio ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Low Frequency ◽  
Cycle Fatigue

Samples of Q345 steel welded joints were tested to failure under low cycle fatigue(LCF),high cycle fatigue(HCF) and combined fatigue(CCF) using an apparatus that is capable of providing interactive LCF/HCF loading. The stress ratio R is 0.5 and the frequency of HCF is about 19kHz. The result indicates that not only high frequency minor cycles superimposed on low frequency major cycles , but also low frequency minor cycles superimposed on high frequency major cycles can do remarkable damage to fatigue performance of welded joints. The CCF strength is characterized by amplitude envelope. If CCF fatigue life is characterized by LCF life, adverse effect of HCF component is underestimated. If CCF fatigue life is characterized by HCF life, adverse effect of LCF component is overrated.

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