Low Cycle Fatigue Life Analysis of Composite Structure Metal Bellows

2021 ◽  
Vol 10 (02) ◽  
pp. 99-106
Author(s):  
就星 范
Keyword(s):  
Fatigue Life ◽  
Composite Structure ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Metal Bellows ◽  
Life Analysis ◽  
Fatigue Life Analysis

Prediction of Low-Cycle Fatigue Life of Specimens With Fabrication Flaws

1968 ◽  
Vol 90 (4) ◽  
pp. 620-626 ◽  
Author(s):  
A. G. Pickett
Keyword(s):  
Fatigue Life ◽  
Crack Initiation ◽  
Low Cycle Fatigue ◽  
Small Specimen ◽  
Cycle Fatigue ◽  
Notch Stress ◽  
Weld Defect ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Crack Initiation Life

A modification of the notch stress procedure for fatigue-life analysis is presented. The importance of considering the mechanics of the specimen and the effects of the notch on specimen mechanics is illustrated by example. The procedure is applied to correlate the results of small specimen tests with large weld defect specimen tests. The significance of crack-initiation life and crack-propagation life and the dependence of these portions of total fatigue life on specimen geometry and loading is developed.

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.

Research on the Very-High-Cycle Fatigue Life Analysis of High-Speed Take-Up Winder

2014 ◽  
Vol 488-489 ◽  
pp. 1281-1284
Author(s):  
Yong Li ◽  
Wen Qin Liu ◽  
Zhou Yang
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
High Speed ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Chemical Fiber ◽  
Cycle Fatigue ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Vibration Performance

The take-up winder is an important equipment of chemical fiber textile machinery. Vibration performance is the key to decide quality and service life of product. The modal of winder is analyzed. It is shown that the rotation speed cannot be kept away from fifth and sixth resonance frequency. The Maximum stress response is calculated by harmonic analysis. According to results of high-cycle fatigue tests, the service life of winder is evaluated. The results show that there is the risk of fatigue damage for small damp ratio. Unlimited fatigue life can be obtained by creasing damp ratio. It can be concluded that creasing damp is an effective way to improve the service life.

Cyclic Fatigue in Metal Bellows

2013 ◽  
Author(s):  
Scott Stelmar
Keyword(s):  
Fatigue Life ◽  
Additional Data ◽  
Low Cycle Fatigue ◽  
Cyclic Fatigue ◽  
Data Sets ◽  
Cycle Fatigue ◽  
Calculation Methods ◽  
Data Set ◽  
Expansion Joints ◽  
Metal Bellows

Engineers who encounter the need for metal bellows expansion joints in piping and heat exchangers are often challenged by cyclic fatigue life calculation methods. ASME has published formulas for predicting low cycle fatigue life of metal bellows. Both B31.3 Appendix X and BPVC VIII Appendix 26 are similar in their approach, but are based on a data set generated in 1986 that produces excessively conservative results. Since that time, members of the Expansion Joint Manufacturers Association and others have provided additional data sets that allow further extension and accuracy of formulaic methods for calculating fatigue life. Additionally the experiments were designed to allow discrimination by various metal classes identifying superior alloys for bellows element performance. Major corrections are possible that will allow increased confidence and economy of design for those engineers that must adhere to the requirements of the American Codes.

Low-Cycle Fatigue Performance of Buckling Restrained Braces and Assessment of Cumulative Damage under Severe Earthquakes

2018 ◽  
Vol 763 ◽  
pp. 867-874
Author(s):  
Yu Shu Liu ◽  
Ke Peng Chen ◽  
Guo Qiang Li ◽  
Fei Fei Sun
Keyword(s):  
Fatigue Life ◽  
Energy Dissipation ◽  
Structural Reliability ◽  
Low Cycle Fatigue ◽  
Engineering Application ◽  
Fatigue Performance ◽  
Cycle Fatigue ◽  
Variable Amplitude ◽  
Buckling Restrained Braces ◽  
Energy Dissipation Devices

Buckling Restrained Braces (BRBs) are effective energy dissipation devices. The key advantages of BRB are its comparable tensile and compressive behavior and stable energy dissipation capacity. In this paper, low-cycle fatigue performance of domestic BRBs is obtained based on collected experimental data under constant and variable amplitude loadings. The results show that the relationship between fatigue life and strain amplitude satisfies the Mason-Coffin equation. By adopting theory of structural reliability, this paper presents several allowable fatigue life curves with different confidential levels. Besides, Palmgren-Miner method was used for calculating BRB cumulative damages. An allowable damage factor with 95% confidential level is put forward for assessing damage under variable amplitude fatigue. In addition, this paper presents an empirical criterion with rain flow algorithm, which may be used to predict the fracture of BRBs under severe earthquakes and provide theory and method for their engineering application. Finally, the conclusions of the paper were vilified through precise yet conservative prediction of the fatigue failure of BRB.

scholarly journals Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4070
Author(s):  
Andrea Karen Persons ◽  
John E. Ball ◽  
Charles Freeman ◽  
David M. Macias ◽  
Chartrisa LaShan Simpson ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Prediction Models ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Wearable Sensors ◽  
Fatigue Tests ◽  
Proof Of Concept ◽  
Cycle Fatigue ◽  
Wearable Sensing ◽  
Failure Data

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from “bench to bedside,” fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

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