Effect of loading-program modifications in rotating-bending tests on fatigue behaviour of aircraft material specimens

1979 ◽  
Vol 10 (9) ◽  
pp. 303-312 ◽  
Author(s):  
A. Buch
Keyword(s):  
Fatigue Behaviour ◽  
Bending Tests ◽  
Aircraft Material ◽  
Rotating Bending

Study of the Effect of DCT and PVD Treatments on the Fatigue Behaviour of AISI 302 Stainless Steel

2009 ◽  
Vol 417-418 ◽  
pp. 49-52 ◽  
Author(s):  
Paolo Baldissera ◽  
Stefano Cavalleri ◽  
Paolo Marcassoli ◽  
Federico Tordini
Keyword(s):  
Stainless Steel ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Cryogenic Treatment ◽  
Fatigue Behaviour ◽  
Combined Effects ◽  
Deep Cryogenic Treatment ◽  
Bending Tests ◽  
Standard Specimens ◽  
Rotating Bending

In this paper the influence of DCT (Deep Cryogenic Treatment) and a CrN arc-deposited PVD (Physical Vapor Deposition) coating on the fatigue behaviour of AISI 302 stainless steel was studied. Rotating bending tests were carried out on standard specimens to evaluate the fatigue limit at 300000 load cycles. The single and the combined effects of the two treatments were investigated by addressing untreated, PVD-coated and both PVD-coated and DC-treated specimens to the tests. All the series of specimens were also tested statically and laboratory analyses including fracture surface SEM observations and hardness measurements were performed.

scholarly journals Fatigue Behaviour of Thin Coated Al 7075 Alloy with Low Temperature PVD Coatings

2013 ◽  
Vol 577-578 ◽  
pp. 221-224 ◽  
Author(s):  
Sergio Baragetti ◽  
Riccardo Gerosa ◽  
Francesco Villa
Keyword(s):  
Aluminium Alloys ◽  
Deposition Temperature ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Pvd Coatings ◽  
Bending Tests ◽  
Al 7075 ◽  
Rotating Bending ◽  
Step Loading ◽  
7075 Alloy

7075-T6 is one of the most performing aluminium alloys, considering its mechanical properties and good fatigue behaviour. In this work the influence of WC/C and DLC PVD coatings on the fatigue behaviour was investigated by rotating bending tests at 2·105cycles. The fatigue behaviour of polished and untreated specimens was considered as reference. In order to decouple the effect of the deposition temperature from the coating one, some uncoated specimens were submitted to the thermal cycles of the WC/C and DLC processes and then tested under fatigue loading. Fatigue life was determined using a step-loading technique. SEM micrographs of the fracture surfaces were taken in order to characterize the fatigue mechanisms of coated and uncoated specimens.

Fatigue Behaviour of Notched PVD-Coated Titanium Components

2007 ◽  
Vol 348-349 ◽  
pp. 313-316 ◽  
Author(s):  
Sergio Baragetti ◽  
Luca Lusvarghi ◽  
F. Pighetti Mantini ◽  
Federico Tordini
Keyword(s):  
Titanium Alloy ◽  
Fatigue Limit ◽  
Fatigue Behaviour ◽  
Bending Tests ◽  
Cross Section Area ◽  
Section Area ◽  
Minimum Cross Section ◽  
Surface Notch ◽  
Rotating Bending ◽  
Pvd Film

In this paper the fatigue behaviour of Ti-6Al-4V alloy coated with a TiN arc-deposited PVD film was studied. Rotating bending tests (R = -1) were carried out on standard “hourglass” specimens to evaluate the fatigue limit at 200000 load cycles. Conventional and notched (120° Vnotch transversal to the rotating axis at the minimum cross section area) specimens were tested, both coated and uncoated, to investigate the effect of the coating on the fatigue limit of the titanium alloy, with and without the surface notch. Fracture surfaces were observed by SEM. The coating did not improve the titanium alloy fatigue life.

On the Decrease of Fatigue Limit Due to Small Prestrain

1992 ◽  
Vol 114 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Y. Nagase ◽  
S. Suzuki
Keyword(s):  
Growth Rate ◽  
Carbon Steel ◽  
Fatigue Limit ◽  
Surface Crack ◽  
Fatigue Behavior ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Small Surface ◽  
Bending Tests ◽  
Rotating Bending

Fatigue behavior of plain specimens of low carbon steel subjected to small tensile prestrain is investigated through rotating bending tests and the mechanism of the decrease of fatigue limit due to the prestrain is discussed. It is found that 3 percent prestraining causes the acceleration of both slip and crack initiations, and increases the growth rate of a small surface crack of less than 0.3 mm. It also decreases the fatigue limit. If prestrained material is aged, the fatigue limit increases. These effects of the small prestrain are explained based on the unpinning of locked dislocations due to the prestrain.

Fatigue Behaviour of DLC Coated Al 7075-T6 Alloy in an Aggressive Mixture

2014 ◽  
Vol 627 ◽  
pp. 81-84 ◽  
Author(s):  
Sergio Baragetti ◽  
Riccardo Gerosa ◽  
Francesco Villa
Keyword(s):  
High Performance ◽  
Contact Fatigue ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Structural Elements ◽  
Pvd Coatings ◽  
Bending Fatigue ◽  
Al 7075 ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

7075-T6 aluminium alloy is commonly adopted in high performance structures and components. Its fatigue behaviour is however dramatically worsened by exposure to aggressive environments. The deposition of PVD coatings, which are commonly adopted to increase the surface properties of structural elements in terms of hardness, contact fatigue and wear resistance, could be beneficial also for the fatigue behaviour of a 7075-T6 substrate in an aggressive environment. In the present work, Diamond Like Carbon (DLC) PVD coated 7075-T6 specimens immersed in methanol have been analysed, by means of step-loading rotating bending fatigue tests (R = -1) at 2·105 cycles. Coated specimens were tested in laboratory air for comparison, and uncoated polished samples were studied in both the environments to obtain reference values. SEM micrographs of the fracture surfaces were taken to investigate the effects of the corrosive environment on the failure mechanism.

scholarly journals Comparative Study on the Fatigue Behaviour of SCC and VC

2014 ◽  
Vol 627 ◽  
pp. 333-336 ◽  
Author(s):  
Sara Korte ◽  
Veerle Boel ◽  
Wouter de Corte ◽  
Geert de Schutter
Keyword(s):  
Crack Width ◽  
Static Load ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Self Compacting Concrete ◽  
Irreversible Damage ◽  
Bending Tests ◽  
Loading Rates ◽  
Four Point Bending ◽  
Concrete Type

Continuous cyclic loading on concrete constructions involves a progressive cracking mechanism, leading to significant changes of the material properties during the lifetime of the structure. Gradually, irreversible damage is inflicted and the carrying capacity is affected, which may cause structural collapse at a stress or strain level much lower than in case of a single static load. This so-called fatigue phenomenon is well-documented in literature for traditional, vibrated concrete (VC), but this is not the case for self-compacting concrete (SCC). Given the fact that this latter concrete type is already used worldwide in many types of structures, including cyclically loaded ones, a good knowledge and understanding of the static and fatigue material behaviour is crucial. Up till now, it is unsure whether SCC performs better, worse, or equally under fatigue loading conditions. Therefore, in this study, destructive four-point bending tests are performed on large beams, made from VC and SCC, both statically and cyclically (at different loading rates). A comparison of the deflection, strain, crack pattern and crack width evolution of the different concrete types is made. The results reveal some significant differences regarding concrete strain and crack width development during the cyclic tests.

scholarly journals Cyclic fatigue behaviour of hydrothermally aged 3Y-TZP ceramics in 4-point bending tests

2021 ◽  
Vol 15 (2) ◽  
pp. 184-194
Author(s):  
Renato Souza ◽  
Roberto Duarte ◽  
Manuel Alves ◽  
Juliana Daguano ◽  
Santos dos ◽  
...  
Keyword(s):  
Bending Strength ◽  
Ceramic Materials ◽  
Cyclic Fatigue ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Bending Test ◽  
Test Results ◽  
Transformation Toughening ◽  
Bending Tests ◽  
M Phase

Fatigue is one of the most important properties to be considered in ceramic dental implants due to cyclic mechanical stresses arising from the chewing process. In this work, the fatigue behaviour of hydrothermally degraded ZrO2-based ceramics stabilized with 3mol% Y2O3 (3Y-TZP) was studied in 4-point bending tests. Samples of 3Y-TZP were compacted (100MPa), sintered at 1475 ?C for 2 h, polished and hydrothermally degraded in an autoclave as described in the ISO-13356 standard. The samples were characterized by their relative density, crystalline phase composition, microstructure and surface roughness. The highly dense (>99.6%TD) sintered 3Y-TZP ceramics has only tetragonal t-ZrO2 phase, even after hydrothermal ageing. Furthermore, the ceramic materials presented a Vickers hardness of 12.7?0.2GPa, a fracture toughness of 7.1?0.3MPa?m1/2 and a 4-point bending strength of 940.1?67MPa. Based on the bending test results 5 different stress levels for the fatigue tests were selected and conducted by cyclic 4-point bending obtaining the S-N curve. Weibull statistics was used for the statistical analysis. The fatigue tests indicate that the limit of fatigue resistance of this 3Y-TZP ceramics is around 550MPa, i.e. higher than the limits established in the ISO-13356 standard for the use of Y-TZP ceramics for the manufacture of implants. The fatigue behaviour of the investigated 3Y-TZP ceramics was related to the toughening mechanisms acting in Y-TZP ceramics, such as transformation toughening related to t?m phase transformation and microcracking.

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