The effect of hole shape on the extent of fatigue life improvement by cold expansions

2009 ◽  
Vol 16 (7) ◽  
pp. 2081-2090 ◽  
Author(s):  
M. Sohel Rana ◽  
C. Makabe ◽  
G. Fujiwara
Keyword(s):  
Fatigue Life ◽  
Hole Shape ◽  
Life Improvement

scholarly journals Fatigue Life Improvement of Cracked Aluminum 6061-T6 Plates Repaired by Composite Patches

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1421
Author(s):  
Armin Yousefi ◽  
Saman Jolaiy ◽  
Reza Hedayati ◽  
Ahmad Serjouei ◽  
Mahdi Bodaghi
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Weight Ratio ◽  
High Strength ◽  
Plastic Strain Amplitude ◽  
Composite Patch ◽  
Life Improvement ◽  
Cracked Structures ◽  
Aluminum Plates ◽  
High Flexibility

Bonded patches are widely used in several industry sectors for repairing damaged plates, cracks in metallic structures, and reinforcement of damaged structures. Composite patches have optimal properties such as high strength-to-weight ratio, easiness in being applied, and high flexibility. Due to recent rapid growth in the aerospace industry, analyses of adhesively bonded patches applicable to repairing cracked structures have become of great significance. In the present study, the fatigue behavior of the aluminum alloy, repaired by a double-sided glass/epoxy composite patch, is studied numerically. More specifically, the effect of applying a double-sided composite patch on the fatigue life improvement of a damaged aluminum 6061-T6 is analyzed. 3D finite element numerical modeling is performed to analyze the fatigue performance of both repaired and unrepaired aluminum plates using the Abaqus package. To determine the fatigue life of the aluminum 6061-T6 plate, first, the hysteresis loop is determined, and afterward, the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted and validated against the available experimental data from the literature. Results reveal that composite patches increase the fatigue life of cracked structures significantly, ranging from 55% to 100% for different applied stresses.

Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment

2011 ◽  
Author(s):  
Yuriy Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Highway Bridges ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving ◽  
Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

MIG Brazing as a Means of Fatigue Life Improvement

2004 ◽  
Vol 48 (9-10) ◽  
pp. 28-40 ◽  
Author(s):  
J. S. Lepistö ◽  
G. B. Marquis
Keyword(s):  
Fatigue Life ◽  
Life Improvement

Fatigue Life Improvement of Parabolic Leaf Springs

1999 ◽  
Vol 41 (6) ◽  
pp. 234-240
Author(s):  
Georgios Savaidis ◽  
Lars Riebeck ◽  
Karl Feitzelmayer
Keyword(s):  
Fatigue Life ◽  
Leaf Springs ◽  
Life Improvement

scholarly journals Fatigue Life Appraisal and Its Corrected Stress Intensity Factor for Repaired Off-CentrallyCracked Aluminum Plates

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4014
Author(s):  
Xiang You ◽  
Zhiyu Wang ◽  
Xiafang Zhou ◽  
Zifeng Liu ◽  
Ruijuan Jiang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Element Model ◽  
Crack Size ◽  
Plate Edge ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Life Improvement ◽  
Edge Cracks ◽  
Aluminum Plates ◽  
Sensitive Parameters

This paper presents an experimental study on the fatigue life estimation of off-centrally cracked aluminum plates. Typical theoretical equations for off-central, central and edge cracks were reviewed and compared in terms of their sensitive parameters and applicability. A finite element model has been validated in its capacity in modelling the influences of eccentricity and crack size on the boundary correction coefficients. The Forman equation has been employed along with numerical results for the prediction of fatigue lives. Based on the test data, the fatigue life results of aluminum plates with and without patched laminate repair have been compared with codified fatigue classes. It is demonstrated that the repair at the crack tip close to the plate edge is effective in the fatigue life improvement for off-centrally crackedaluminum plates.

scholarly journals Fatigue Life Improvement of the High Strength Steel Welded Joints by Ultrasonic Impact Peening

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 619 ◽  
Author(s):  
Ján Lago ◽  
Libor Trško ◽  
Michal Jambor ◽  
František Nový ◽  
Otakar Bokůvka ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Welded Joints ◽  
Compressive Residual Stress ◽  
High Strength ◽  
Fatigue Properties ◽  
Low Alloy Steel ◽  
Residual Stress Field ◽  
Near Surface ◽  
Life Improvement

Ultrasonic impact peening was applied on welded joints manufactured from Strenx 700 MC high strength low alloy steel with the aim to improve the fatigue properties. Three different surface treatment parameters were tested, which resulted in transformation of the near-surface tensile residual stresses in the weld metal and heat affected zone to compressive residual stress field, while maximal values from −400 MPa up to −800 MPa were reached. The highest fatigue life improvement was reached by the double peening with the 85 N contact force, where the fatigue limit for N = 108 cycles increased from 370 MPa to 410 MPa.

Fatigue Life Improvement in Lean Duplex Stainless Steel by Peening Treatments

2019 ◽  
Vol 50 (12) ◽  
pp. 5614-5626 ◽  
Author(s):  
Renata Strubbia ◽  
Silvina Hereñú ◽  
Gilberto Gómez-Rosas ◽  
Valeria Fuster ◽  
Carlos Rubio González
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Duplex Stainless Steel ◽  
Lean Duplex Stainless Steel ◽  
Life Improvement

Weld detail fatigue life improvement techniques. Part 1: review

1999 ◽  
Vol 12 (6) ◽  
pp. 447-474 ◽  
Author(s):  
K.J. Kirkhope ◽  
R. Bell ◽  
L. Caron ◽  
R.I. Basu ◽  
K.-T. Ma
Keyword(s):  
Fatigue Life ◽  
Life Improvement

Exploring Autofrettage Process to Improve the Fatigue Life on High-Pressure Cylinder

2013 ◽  
Vol 457-458 ◽  
pp. 518-521
Author(s):  
Feng Ling Yang ◽  
Shi Jin Zhang
Keyword(s):  
High Pressure ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Analysis ◽  
High Pressure Cylinder ◽  
Pressure Cylinder ◽  
Surface Variation ◽  
Life Improvement ◽  
Improve Fatigue Strength ◽  
Improve Fatigue

Autofrettage process is now widely used to improve fatigue strength of high pressure components. This paper focuses on the fatigue life improvement of the high-pressure cylinder treated by autofrettage process. In this process, a high pressure cylinder treated by autofrettage process has been simulated by using FEA software, and surface variation of the cylinder has been analyzed. To further understand this process, theoretical fatigue analysis has also been carried out.

scholarly journals Robustness of the HFMI techniques and the effect of weld quality on the fatigue life improvement of welded joints

2020 ◽  
Vol 64 (11) ◽  
pp. 1947-1956
Author(s):  
R. Aldén ◽  
Z. Barsoum ◽  
T. Vouristo ◽  
M. Al-Emrani
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Fatigue Testing ◽  
Considerable Effect ◽  
Quality Level ◽  
Weld Quality ◽  
Treatment Results ◽  
Life Improvement ◽  
Consistent Treatment ◽  
Good Agreement

Abstract Robustness of HFMI treatment in different weld qualities according to ISO 5817 was studied, and fatigue testing of the treated samples was carried out in order to investigate the effect of the weld quality prior treatment. The results show that HFMI-treated welds with weld quality level D shows fatigue life improvements that fall within the IIW recommendations for HFMI. No significant influence from the HFMI operator or HFMI equipment on the fatigue life was found. However, the scatter in fatigue testing results varied with HFMI operator and indicated that different HFMI operators could produce consistent treatment results. A considerable effect on fatigue life from HFMI tool radius was found, where the 2-mm tool radius showed considerably greater fatigue life compared with the 1.5-mm tool radius. According to IIW (Marquis and Barsoum 2016), for steel grade SY = 700 MPa, the fatigue strength recommendation is FAT 160 (m = 5) for transverse stiffener–welded joints with as-welded quality B according to ISO 5817 (ISO/TC 44/SC 10 2011), prior to treatment. It can be observed in the current study that fatigue-tested HFMI-treated welded joints, welded with weld quality D, are in good agreement with the IIW recommendations.

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