Fatigue Crack Propagation Behavior of 2091 T8 and 2024 T3 Under Constant and Variable Amplitude Loading

Ohrloff, Nikolaus; Gysler, A.; Lütjering, G.

doi:10.1051/jphyscol:1987394

Cited by 19 publications

(22 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Lo-Hi sequence produces an acceleration of crack growth rate, above the steady state level expected for the high block, followed by a gradual reduction to the corresponding steady-state DK 2 level. This behaviour is identical to that generally observed following an underload [27]. The trends illus- [19].…”

Section: Transient Crack Growth Behavioursupporting

confidence: 70%

Partial crack closure under block loading

Borrego

Ferreira

Costa

2008

International Journal of Fatigue

View full text Add to dashboard Cite

Fatigue crack propagation tests under high-low and low-high block loading sequences have been performed in aluminium alloy specimens. The tests were carried out at constant DK conditions. Two stress ratios were analysed: R = 0.05 and R = 0.4. Crack closure was monitored in all tests by the compliance technique using a pin microgauge. The observed transient post load step behaviour is discussed in terms of the load change magnitude, DK baseline levels and stress ratio. The crack closure level was obtained and compared with the crack growth transients. A good agreement between experimental and predicted crack growth rates is obtained when the partial crack closure effect is properly taken into account. Therefore, plasticity-induced crack closure plays an important role on the load interaction effects observed in aluminium alloys.

show abstract

Section: Transient Crack Growth Behavioursupporting

confidence: 70%

Partial crack closure under block loading

Borrego

Ferreira

Costa

2008

International Journal of Fatigue

View full text Add to dashboard Cite

show abstract

“…2(b) shows clearly that during the stable crack growth rate stage crack growth retardation increases with DK under remotely spaced overloads (n BL R100). Moreover, as observed in similar tests performed by Iwasaki et al [9] in SM50B steel and by Ohrloff et al [10] in 2024-T6 and 2091-T8 aluminium alloys, also in AlMgSi1-T6 aluminium alloy, the crack growth acceleration phenomenon observed under too closely spaced overloads decreases with DK. During this phase, the acceleration phenomenon changes even to crack growth retardation for DK values above approximately 10 MPa m 1/2 .…”

Section: Typical Transient Behaviour and Periodicity Effect Of Singlesupporting

confidence: 67%

“…Initially, a retardation period identical to that induced by a single peak overload [3][4][5] is observed for less frequently applied overloads. For overloads applied each 10 baseline cycles this initial stage is similar to the one generally observed after an underload [10,11]. The subsequent crack growth rate increases in a stable manner.…”

Section: Typical Transient Behaviour and Periodicity Effect Of Singlesupporting

confidence: 56%

See 1 more Smart Citation

Fatigue crack growth in thin aluminium alloy sheets under loading sequences with periodic overloads

Borrego¹,

Costa

Ferreira

2005

Thin-Walled Structures

View full text Add to dashboard Cite

This study analyses the fatigue crack growth behaviour in thin AlMgSi1-T6 aluminium alloy sheets under several loading sequences containing periodic overloads. The observed fatigue crack growth behaviour is compared to constant amplitude loading and discussed in terms of type of loading sequence, intermediate baseline cycles and stress ratio. The crack closure parameter U was obtained for periodic single overload tests and compared with the crack growth transients. Crack retardation increases with overload periodicity and decreases with stress ratio increase. Higher crack growth retardation was observed under loading sequences with decreasing load levels in comparison to increasing ones as well as under loading sequences with extended periodicity. In spite of some discrepancy, attributed to the quick change of the closure levels, it is clear that plasticity-induced crack closure plays an important role on the load interaction effects observed in this aluminium alloy. q

show abstract

“…Skorupa analysed several works (43,(52)(53)(54)(55)(56)(57)(58) that showed that an underload applied after an overload can generate reverse plasticity ahead of the crack tip which partially nullifies the beneficial retardation effect of the overload.…”

Section: Effect Of Applying Underloadsmentioning

confidence: 99%

Determination of crack growth for 6082-T6 aluminium subjected to periodic single and block overloads and underloads using a two dimensional finite element model

Espinosa

Fellows

Durodola

et al. 2017

International Journal of Fatigue

View full text Add to dashboard Cite

ABSTRACT:The estimation of crack growth under variable amplitude loading is complex due to interaction effects such as plasticity, crack tip blunting, residual stresses, crack tip closure and crack tip branching. Crack closure has been identified to be one of the main interaction effects. In order to study the effect of crack closure the authors have previously carried out experimental testing to obtain more accurate measurements of crack opening and closure (1, 2). They have also developed two dimensional plane stress Finite Element models utilising high mesh density whilst maintaining the ability to measure crack growth over long crack lengths (3). This initial work has been extended in this paper to examine the effects of single and block overloads and random spectrum loading on crack growth. The crack length distance that is affected by overloads and underloads measured experimentally and predicted numerically are shown to be very close when using cyclic hardening material properties and kinematic hardening. In addition the comparison of experimental and numerical crack growth versus crack length graphs shows good correlation of the crack growth acceleration and retardation after the applied overload which has not been seen previously. These comparisons seem to be a very useful tool to validate numerical models.

show abstract

Fatigue Crack Propagation Behavior of 2091 T8 and 2024 T3 Under Constant and Variable Amplitude Loading

Cited by 19 publications

References 1 publication

Partial crack closure under block loading

Partial crack closure under block loading

Fatigue crack growth in thin aluminium alloy sheets under loading sequences with periodic overloads

Determination of crack growth for 6082-T6 aluminium subjected to periodic single and block overloads and underloads using a two dimensional finite element model

Contact Info

Product

Resources

About