On the fatigue behavior of duplex and high-strength welded cruciform joints

2021 ◽  
Vol 247 ◽  
pp. 113161
Author(s):  
Burak Karabulut ◽  
Barbara Rossi
Keyword(s):  
Fatigue Behavior ◽  
High Strength ◽  
Cruciform Joints

scholarly journals Fatigue Properties of Cruciform and Flange-gusset Joints Using Normal and High Strength Steels

2020 ◽  
Author(s):  
Balázs József Mecséri ◽  
Balázs Kövesdi
Keyword(s):  
Fatigue Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Steel Grade ◽  
Fatigue Properties ◽  
Test Results ◽  
Stress Range ◽  
Fatigue Lifetime ◽  
Cruciform Joints ◽  
Normal Strength

The objective of this paper is to investigate and compare the fatigue behavior of Normal Strength Steel (NSS) and High Strength Steel (HSS) welded specimens (cruciform and flange gusset joints). Numerous specimens were tested in the framework of the research project. The experimental S-N curves of the test specimens are determined and analyzed by mathematical statistics to consider the uncertainties and scatter of test results. Statistical analysis of the S-N curves showed that the fatigue behavior of as-welded flange gusset joints is identical in the cases of HSS and NSS specimens, which means that there is no difference in the fatigue lifetime depending on the steel grade. However, the as-welded HSS cruciform joints can be more favorable and their fatigue lifetime is longer than the specimens made from NSS, if the stress range is below 100 MPa. The current study shows that the fatigue behavior of as-welded HSS details depends on the geometry of the investigated specimens and its fatigue lifetime can be larger in the small stress range region than for NSS specimens.

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.

Constant-amplitude fatigue behavior of M24 high-strength bolt of end-plate flange connection

Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 2041-2053
Author(s):  
Jinfeng Jiao ◽  
Zhanxiang Liu ◽  
Qi Guo ◽  
Yong Liu ◽  
Honggang Lei
Keyword(s):  
Fatigue Behavior ◽  
High Strength ◽  
Constant Amplitude ◽  
Flange Connection ◽  
End Plate ◽  
High Strength Bolt

scholarly journals Changing in Fatigue Life of 300 M Bainitic Steel After Laser Carburizing and Plasma Nitriding

2018 ◽  
Vol 165 ◽  
pp. 21002 ◽  
Author(s):  
Antonio J. Abdalla ◽  
Douglas Santos ◽  
Getúlio Vasconcelos ◽  
Vladimir H. Baggio-Scheid ◽  
Deivid F. Silva
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
High Strength ◽  
Tensile Tests ◽  
Steel Sample ◽  
Fatigue Tests ◽  
300M Steel ◽  
Structural Applications

In this work 300M steel samples is used. This high-strength steel is used in aeronautic and aerospace industry and other structural applications. Initially the 300 M steel sample was submitted to a heat treatment to obtain a bainític structure. It was heated at 850 °C for 30 minutes and after that, cooled at 300 °C for 60 minutes. Afterwards two types of surface treatments have been employed: (a) using low-power laser CO2 (125 W) for introducing carbon into the surface and (b) plasma nitriding at a temperature of 500° C for 3 hours. After surface treatment, the metallographic preparation was carried out and the observations with optical and electronic microscopy have been made. The analysis of the coating showed an increase in the hardness of layer formed on the surface, mainly, among the nitriding layers. The mechanical properties were analyzed using tensile and fatigue tests. The results showed that the mechanical properties in tensile tests were strongly affected by the bainitic microstructure. The steel that received the nitriding surface by plasma treatment showed better fatigue behavior. The results are very promising because the layer formed on steel surface, in addition to improving the fatigue life, still improves protection against corrosion and wear.

Development of a High Strength Mg-Zn-Y-Zr Wrought Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 1701-1706
Author(s):  
Rong Shi Chen ◽  
Wei Neng Tang ◽  
Dao Kui Xu ◽  
En Hou Han
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Fatigue Life ◽  
Deformation Behavior ◽  
Fatigue Behavior ◽  
High Strength ◽  
Zn Content ◽  
High Fatigue ◽  
Content Range ◽  
Zr Alloy

The effects of Y addition to the Mg-Zn-Y-Zr alloy on the change of the microstructure and the mechanical properties (with the Y content range of 1 to 3 wt%) have been investigated. It shows that when Zn content is constant (5.65wt%), the alloys with Y content between 1.17 and 1.72wt% nearly reach its highest strength. With the composition near the optimums, the extruded Mg-6%Zn-1%Y-Zr alloy shows high strength and excellent ductility. The deformation behavior of this new alloy at high temperature has also been studied. Moreover, the super-long fatigue behavior of the Mg-6%Zn-1%Y-Zr alloy has also been tested, the results show the alloy with a high fatigue strength of about 85-90MPa in the super-long fatigue life regime of 1×109 cycles.

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