An Analysis of Rotating Bending Fretting Fatigue Tests Using Bridge Specimens

2008 ◽  
pp. 404-404-19 ◽  
Author(s):  
M Ciavarella ◽  
G Demelio ◽  
A HillsD
Keyword(s):  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Rotating Bending

Single wire fretting fatigue tests for electrical conductor bending fatigue evaluation

Wear ◽  
1995 ◽  
Vol 181-183 ◽  
pp. 537-543 ◽  
Author(s):  
Z.R. Zhou ◽  
S. Goudreau ◽  
M. Fiset ◽  
A. Cardou
Keyword(s):  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Electrical Conductor ◽  
Single Wire ◽  
Bending Fatigue ◽  
Fatigue Evaluation

On the Effect of Electrodischarge Drilling on the Fatigue Life of Inconel 718

2014 ◽  
Vol 891-892 ◽  
pp. 1451-1456
Author(s):  
Elena Bassoli ◽  
Andrea Baldini ◽  
Andrea Gatto ◽  
Antonio Strozzi ◽  
Lucia Denti
Keyword(s):  
Fatigue Life ◽  
Inconel 718 ◽  
Metal Cutting ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Aerospace Applications ◽  
Rotating Bending Fatigue ◽  
Cutting Operation ◽  
Rotating Bending ◽  
Superposition Effect

Difficult-to cut-materials are associated with premature tool failure, most likely in the case of complex geometries and this shapes. However, Nickel-based alloys are commonly used in high-temperature and aerospace applications, where thin deep holes are often required. Then, the only viable manufacturing solution relies on non-contact processes, like electrodischarge (ED) drilling. Morphology of ED machined surfaces is significantly different than obtained by metal-cutting operation and is known to jeopardize fatigue strength, but the extent needs to be gauged and related to the process parameters. Aim of the paper is to study the effect of holes (0.8 mm diameter, aspect ratio 10) produced by ED drilling on the fatigue life of Inconel 718. Rotating bending fatigue tests are carried out on specimens drilled under two ED setups, as well as with a traditional cutting tool. Specimens free from holes are fatigued under the same conditions for comparison. Based on previous studies, extremal ED parameters are selected, giving best surface finish versus highest productivity. S-N curves show that the ED process causes a decrease of the fatigue resistance with respect to traditional drilling, whereas the effect of different ED setups is negligible. Maximum productivity can thus be pursued with no threat to fatigue performance. The fatigue limit variation is quantified by using the superposition effect principle: ED drilling causes an increase of the stress concentration factor around 25% if compared to traditional drilling. The macroscopic fatigue behavior is integrated with a study of the effects of the different drilling processes in the micro-scale, by means of a microstructural and fractographic analysis.

The Effects of Periodic High Loads on Fretting Fatigue

1981 ◽  
Vol 103 (3) ◽  
pp. 223-228 ◽  
Author(s):  
A. Kantimathi ◽  
J. A. Alic
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Growth Retardation ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Constant Amplitude ◽  
Axial Loads ◽  
Prolonged Fatigue ◽  
Stress Ratios ◽  
Crack Growth Retardation

Fretting fatigue tests have been conducted on 7075-T7351 aluminum alloy coupons with fretting pads of the same material. Three different stress ratios were used, the otherwise constant amplitude axial loads being interrupted every 1000 cycles by either tensile overloads to 400 MPa or compressive underloads to −200 MPa. Tensile overloads greatly prolonged fatigue life for low stresses where the overload ratios were 1.6 and above; compressive underloads had comparatively little effect. The results are discussed in terms of crack growth retardation phenomena.

Mechanical Approach for Predicting Fretting Fatigue Strength

2010 ◽  
Vol 452-453 ◽  
pp. 797-800
Author(s):  
M. Jayaprakash ◽  
Yoshiharu Mutoh ◽  
K. Asai ◽  
Kunihiro Ichikawa ◽  
Shigeo Sakurai
Keyword(s):  
Fatigue Strength ◽  
Compressive Stress ◽  
Tangential Stress ◽  
Steel Specimen ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Stress Range ◽  
Element Analysis ◽  
Mechanical Approach ◽  
Good Agreement

Stress distribution at the contact edge is known to have a dominant influence on fretting fatigue strength. Stresses acting on the contact surface are tangential stress and compressive stress. In the present study, fretting fatigue strengths of 12 Cr steel specimen under two different mean stresses have been predicted based on the generalized tangential stress range - compressive stress range diagram. The generalized tangential stress range - compressive stress range diagram was obtained by carrying out fretting fatigue tests and finite element analysis using various steel specimens with various geometries of contact pad from the previous studies. The predicted fretting fatigue strengths were in good agreement with the experimental results.

Fretting fatigue tests and crack initiation analysis on zircaloy tube specimens

2014 ◽  
Vol 63 ◽  
pp. 154-161 ◽  
Author(s):  
Lichen Tang ◽  
Shurong Ding ◽  
Hao Qian ◽  
Yongcheng Xie ◽  
Yongzhong Huo
Keyword(s):  
Crack Initiation ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Zircaloy Tube

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.

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