A history of fatigue

Schütz, W.

doi:10.1016/0013-7944(95)00178-6

Cited by 416 publications

(226 citation statements)

References 28 publications

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“…[1] Since that time, researchers have been in search of metals that are either impervious or highly resistant to fatigue failure. The advent of nanocrystalline (NC) metals, [2] with their superior strength and hardness to conventional coarse-grained (CG) counterparts, offers the possibility of a new metallurgical pathway to improved fatigue performance.…”

Section: Introductionmentioning

confidence: 99%

Anomalous Fatigue Behavior and Fatigue-Induced Grain Growth in Nanocrystalline Nickel Alloys

Boyce

Padilla

2011

Metall Mater Trans A

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Fatigue failure due to repetitive loading of metallic devices is a pervasive engineering concern. The present work reveals extraordinary fatigue resistance in nanocrystalline (NC) alloys, which appears to be associated with the small (<100 nm) grain size inhibiting traditional cyclic damage processes. In this study, we examine the fatigue performance of three electrodeposited NC Nibased metals: Ni, Ni-0.5Mn, and Ni-22Fe (PERMALLOY). When subjected to fatigue stresses at and above the tensile yield strength where conventional coarse-grained (CG) counterparts undergo low-cycle fatigue failure (<10 4 cycles to failure), these alloys exhibit exceptional fatigue lives (in some cases, >10 7 cycles to failure). Postmortem examinations show that failed samples contain an aggregate of coarsened grains at the crack initiation site. The experimental data and accompanying microscopy suggest that the NC matrix undergoes abnormal grain growth during cyclic loading, allowing dislocation activity to persist over length scales necessary to initiate a fatigue crack by traditional fatigue mechanisms. Thus, the present observations demonstrate anomalous fatigue behavior in two regards: (1) quantitatively anomalous when considering the extremely high stress levels needed to drive fatigue failure and (2) mechanistically anomalous in light of the grain growth process that appears to be a necessary precursor to crack initiation.

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Section: Introductionmentioning

confidence: 99%

Anomalous Fatigue Behavior and Fatigue-Induced Grain Growth in Nanocrystalline Nickel Alloys

Boyce

Padilla

2011

Metall Mater Trans A

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“…In the absence of knowledge with respect to the driving forces of the system, the statespace model described in Eqs. (2) and (3) may be written in the augmented form. This is accomplished by supplementing the initial state vector with the input force vector in order to construct an augmented state vector as follows…”

Section: Response Estimationmentioning

confidence: 99%

“…Although fatigue has been vastly and exhaustively investigated under different perspectives [2], not many studies have been relied on a probabilistic framework. In recent years, an attempt has been made to approach damage accumulation due to fatigue as a stochastic process [3].…”

Section: Introductionmentioning

confidence: 99%

Reliability Prediction of Fatigue Damage Accumulation on Wind Turbines Support Structures

Tatsis¹,

Chatzi²,

Lourens³

2017

Proceedings of the 2nd International Conference on Uncertainty Quantification in Computational Sciences and Engineering (UNCECO

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Abstract. The evaluation of fatigue damage accumulation on wind turbine support structures under operational conditions is heavily influenced by a number of uncertainties. These uncertainties may, firstly, be attributed to the highly variable and complex environmental loads, and secondly, to the unavoidable modelling errors which mainly originate from the inherent randomness in both material properties and fatigue resistance of structural components. It is therefore essential that assessment of fatigue life is carried out within a probabilistic framework; one that accounts for the stochastic nature of the phenomenon. The present study proposes a strategy for real-time reliability prediction of accumulated fatigue damage on wind turbine support structures by taking into account the above-mentioned uncertainties. To this end, the availability of structural monitoring information for the identification of the global response on wind-turbine support structures is exploited in order to address the discrepancies between actual and predicted damage accumulation. This is carried through utilization of an augmented version of the Kalman filter, which is capable of jointly estimating the response and the unknown inputs of the structure while relying on a limited number of noisy observations and a presumably uncertain model of the real system. A fixed-lag smoother is further deployed for the attenuation of the estimation error in an on-line mode and the smoothed stochastic estimates of the response are propagated over the model at the level of stresses. The accumulated damage along with the corresponding reliability level is finally predicted using a stochastic nonstationary fatigue damage model. The proposed scheme is demonstrated via implementation on the NREL 5.0 MW wind turbine under different operational conditions, on the basis of dummy vibration data generated via the FAST software.

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“…Wöhler considered that engineers must have the knowledge of the loads in order to design against fatigue 19 . Therefore load control is the simplest way to check for fatigue performance on a real test as it does not have to account the non-linearity from the material curves, as well as it can be cycled in much higher frequency compared to a strain controlled test program.…”

Section: Testing Program and Reliability Analysismentioning

confidence: 99%

From numerical calculations to materials testing homologation: a biaxial fatigue reliability prediction methodology for structural components

2013

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This article investigates a fatigue approach conducted from the design phase to testing approval. It considerers modern analytical and experimental tools for structural durability assessment over each development phase for two reference components aiming an early approval methodology validation for a new design. A Finite element analysis procedure was used to set critical spots for measurements minimizing the data acquisition efforts. Based on measured data, strain life calculation was done for two reference components in order to set the release goals for a new design submitted to this approach. An innovative fatigue experimental technique is proposed using component extracted specimens and an edited input cycle loads. Considering the random data from a standard test track and signal proportionality evaluation, while assuming the Brown Miller equation for bi-axial fatigue together with Ramberg-Osgood model, equivalent damage load blocks were edited and used as input for durability assessment on specimens representing the component material. The results for the three parts materials were plotted as Weibull diagram for B10 life estimation. Fatigue life results showed good correlation with the reference parts structural performance thus validating the method as well as approving the new design for production without additional on-vehicle durability testing. The methodology and the fatigue testing proposal is therefore recommended for future applications on similar developments.

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A history of fatigue

Cited by 416 publications

References 28 publications

Anomalous Fatigue Behavior and Fatigue-Induced Grain Growth in Nanocrystalline Nickel Alloys

Anomalous Fatigue Behavior and Fatigue-Induced Grain Growth in Nanocrystalline Nickel Alloys

Reliability Prediction of Fatigue Damage Accumulation on Wind Turbines Support Structures

From numerical calculations to materials testing homologation: a biaxial fatigue reliability prediction methodology for structural components

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