Damage Tolerant Analysis of Stiffened Aluminium Alloy Panels Under Fatigue Loading

2014 ◽  
Author(s):  
A. Ramachandra Murthy ◽  
G. S. Palani ◽  
Smitha Gopinath ◽  
Nagesh R. Iyer
Keyword(s):  
Aluminium Alloy ◽  
Fatigue Loading ◽  
Damage Tolerant

Investigation of the Stress Fields Around a Fatigue Crack in Aluminium Alloy 5091

2008 ◽  
Vol 571-572 ◽  
pp. 119-124 ◽  
Author(s):  
M. Rahman ◽  
Michael E. Fitzpatrick ◽  
Lyndon Edwards ◽  
S. Pratihar ◽  
Matthew J. Peel ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Aluminium Alloy ◽  
Crack Tip ◽  
Fatigue Loading ◽  
Compact Tension ◽  
European Synchrotron Radiation Facility ◽  
Stress Fields ◽  
Small Scale ◽  
X Ray Diffraction ◽  
X Ray

There have been many theoretical studies to predict the stress fields around the tip of a growing fatigue crack. However, until recently the highly-localized, small scale nature of the stresses has meant that direct measurement has not been possible. With the current generation of synchrotron X-ray sources, sub-millimetre sampling dimensions are now possible, and it has become possible to evaluate directly the stresses at the tip of a fatigue crack and to see how the stresses evolve as the result of an overload, for example. In this paper we present results of synchrotron X-ray diffraction analysis of the stress fields around a fatigue crack in aluminium alloy 5091 (Al-Mg-Li-C-O); this is a dispersion-strengthened alloy with a fine grain size, which makes it ideal for such experiments. Compact tension (CT) specimens were prepared with constant amplitude fatigue loading. The energy dispersive X-ray diffraction (EDXRD) technique was used for measuring strains around the crack tip along the mid thickness of the specimen under in-situ loading. The measurement was carried out at the ESRF (European Synchrotron Radiation Facility), Grenoble, France on the ID15A beam line. The experimental crack tip stresses have been compared with the analytical fracture mechanics solution.

scholarly journals Damage tolerant evaluation of cracked stiffened panels under fatigue loading

Sadhana ◽  
2012 ◽  
Vol 37 (1) ◽  
pp. 171-186 ◽  
Author(s):  
A RAMA CHANDRA MURTHY ◽  
G S PALANI ◽  
NAGESH R IYER
Keyword(s):  
Fatigue Loading ◽  
Stiffened Panels ◽  
Damage Tolerant

Load Sequence Effect on Fatigue Damage

2011 ◽  
Vol 488-489 ◽  
pp. 545-548 ◽  
Author(s):  
Y.G. Xu ◽  
L. Wang ◽  
Y. Chen ◽  
W. Tiu
Keyword(s):  
Fatigue Damage ◽  
Crack Closure ◽  
Life Prediction ◽  
Fatigue Cracks ◽  
Fatigue Loading ◽  
Sequence Effect ◽  
Complex Load ◽  
Load Sequence ◽  
Damage Tolerant ◽  
Spectrum Loading

Reliable damage tolerant design of airframe structures relies on the accurate life prediction of fatigue cracks propagating from a detectable size to the critical size, which is challenging due to the complex load sequence effect under spectrum loading. This paper aims at gaining a further understanding of the complex influence of the loading history on fatigue damage through a detailed numerical simulation of the near-tip crack behaviour using the crack closure concept. The spectrum loading is broken down into a number of simple yet representative loading scenarios with overload/underload superimposed onto the baseline constant amplitude fatigue loading. Detailed finite element (FE) simulation of the plasticity-induced crack closure (PICC) has been carried out to catch the transient behaviour of PICC and link it to the fatigue damage. The load interaction effect has been analysed with the aim to identify the possible dominant loading cycle which could simplify the fatigue life prediction process in the industry. It is concluded that more reliable damage tolerant design can be achieved if the load sequence effect on fatigue damage can be taken into account more accurately for a structure under spectrum loadings.

Evolution of residual stresses with fatigue loading and subsequent crack growth in a welded aluminium alloy middle tension specimen

2008 ◽  
Vol 75 (13) ◽  
pp. 3881-3894 ◽  
Author(s):  
C.D.M. Liljedahl ◽  
M.L. Tan ◽  
O. Zanellato ◽  
S. Ganguly ◽  
M.E. Fitzpatrick ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Aluminium Alloy ◽  
Crack Growth ◽  
Fatigue Loading ◽  
Tension Specimen

Weibull Analysis of the Effect of Modified Aging Treatments on Fatigue Life of Cast Aluminium Alloy 354

2013 ◽  
Vol 800 ◽  
pp. 356-360 ◽  
Author(s):  
Salil Sainis ◽  
Aakarshit Kalra ◽  
G. Dinesh Babu ◽  
M. Nageswara Rao
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Ultimate Tensile Strength ◽  
Aluminium Alloy ◽  
Artificial Aging ◽  
Aging Treatment ◽  
Fatigue Loading ◽  
Weibull Analysis ◽  
Compressor Wheel ◽  
Cast Aluminium

Cast aluminium alloy 354 has extensive applications in the automobile industry. Due to its attractive combination of mechanical properties and excellent castability, it is being used in production of automobile components like the compressor wheel for turbochargers. Performance of this component under fatigue loading conditions is a critical issue. The present study explores the possibility of improving the fatigue life of the component by bringing in process changes (i) adopting a two-step aging treatment in place of the normally used single step aging treatment (ii) adopting a lower artificial aging temperature (171°C) instead of the temperature normally used for artificial aging (188°C) while performing T61 treatment. In all cases Weibull analysis of fatigue test results was carried out. Weibull analysis of Ultimate Tensile Strength (UTS) values obtained after artificial aging at 171°C and 188°C was also carried out. Among the four variants of two-step aging treatment carried out, the one consisting of 100°C for 5 hours followed by 170°C for 5 hours was found to have the best characteristic fatigue life for the components. The modified T61 treatment where aging was carried out at 171°C instead of the normally used 188°C yielded better characteristic fatigue life as well as better Ultimate Tensile Strength (UTS).

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