The merging of fatigue and fracture mechanics concepts: a historical perspective

Newman, James C.

doi:10.1016/s0376-0421(98)00006-2

Cited by 145 publications

(64 citation statements)

References 6 publications

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“…Under constant amplitude loading, a set of empirical equations has been developed by Newman 19 based on the results obtained by the numerical method 7 . For completeness, these equations are quoted below,…”

Section: Analysis Of Three‐dimensional Constraint Factorsmentioning

confidence: 99%

“…When the baseline fatigue crack growth curves generated using standard specimens (often under plane strain conditions) are applied to predict the fatigue life of engineering structures of thin cross‐section, the differences in the in‐plane and out‐of‐plane constraints may significantly affect the accuracy of predictions 1 –5 . While this effect has been attributed to the transition from flat‐to‐slant crack growth in thin structures, 6 quantitative modelling of the dependence of fatigue crack growth rates on the thickness has mainly been achieved through the use of an effective stress intensity factor 6 , 7 . Such an approach implicitly assumes that the crack tip plastic blunting behaviour, which can be expected to control the crack growth increment, the main mechanism by which fatigue crack propagates, is unaffected by the constraint loss.…”

Section: Introductionmentioning

confidence: 99%

“…In analysing the effect of thickness on fatigue crack growth, the most widely employed method 3 , 4 , 7 is to assume that the fatigue crack growth rate is uniquely characterized by the effective stress intensity factor range, Δ K eff ,…”

Section: Introductionmentioning

confidence: 99%

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The influence of cross‐sectional thickness on fatigue crack growth

Guo

Wang

Rose

1999

Fatigue Fract Eng Mat Struct

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For thin structures, fatigue crack growth rates may vary with the structure's thickness for a given stress intensity factor range. This effect is mainly due to the change in the nature of the plastic deformation when the plastic zone size becomes comparable with, or greater than, the cross‐sectional thickness. Variations in the constraint affect both the crack tip plastic blunting behaviour as well as the fatigue crack closure level. Approximate expressions are constructed for the constraint factor based on asymptotic values and numerical results, which are shown to correlate well with finite element results. It is demonstrated that the present results not only permit predictions of the specimen thickness effects on fatigue crack propagation under spectrum loading, but also eliminate the need to determine the constraint factor by curve‐fitting crack growth data.

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Section: Analysis Of Three‐dimensional Constraint Factorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The influence of cross‐sectional thickness on fatigue crack growth

Guo

Wang

Rose

1999

Fatigue Fract Eng Mat Struct

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“…2 Among the number of crack-closure mechanisms that have been identified (see, e.g. 2 Among the number of crack-closure mechanisms that have been identified (see, e.g.…”

Section: Introductionmentioning

confidence: 99%

Closure of plane‐strain cracks under large‐scale yielding conditions

Wang¹,

Rose²,

Newman³

2002

Fatigue Fract Eng Mat Struct

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This paper presents computational and theoretical investigations of the plasticity‐induced crack‐closure of a plane‐strain crack under large‐scale yielding conditions. Solutions of the crack‐tip opening displacements for a stationary crack and a growing fatigue crack have been obtained using the finite element method. The self‐similar crack‐closure model has been extended to the plane strain case by introducing two plastic constraint factors: one for tension yielding and the other for compression yielding. These two plastic constraint factors are identified by matching the model predictions with the computational results. It is shown that the first constraint factor decreases rapidly with the applied stress while the second constraint factor is approximately equal to unity. The findings of this study allow the cohesive‐zone based crack‐closure model to be extended to plane‐strain cracks, especially under large‐scale yielding conditions.

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“…Fatigue life is thus specified by the number of stress cycles of a specified character that a specimen sustains before failure of a specified nature occurs. It is amazing to note that the interest in studying structural fatigue damage is exponentially increasing as reflected by the review articles dealing with different aspects of fatigue life prediction methods (Orowan 1948;Newman 1998;Cui 2002).…”

Section: Introduction and Background Of Structural Life Assessmentmentioning

confidence: 99%

Overview of Structural Life Assessment and Reliability, Part I: Basic Ingredients of Fracture Mechanics

Ibrahim¹

2015

j ship prod des

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Structural life assessment periodically evaluates the state and condition of a structural system and provides recommendations for possible maintenance actions or the end of structural service life. It is a diversified field and relies on the theories of fracture mechanics, fatigue damage process, probability of failure, and reliability. With reference to naval ship structures, their life assessment is not only governed by the theory of fracture mechanics and fatigue damage process, but by other factors such as corrosion, grounding, and sudden collision. The purpose of this series of review articles is to provide different issues pertaining to structural life assessment of ships and ocean structures. Part I deals with the basic ingredients of the theory of fracture mechanics, which is classified into linear elastic fracture mechanics and elasto-plastic fracture mechanics. The amount of energy available for fracture is usually governed by the stress field around the crack, which is measured by the stress intensity factor. The value of the stress intensity factor, which depends on the loading mode, is evaluated by different methods developed by many researchers. The applications of the theory of fracture mechanics to metallic and composite structures are presented with an emphasis to those used in marine structures. When the inertia of relatively large pieces of a structure is large enough that the correct balancing of the energy of fracture requires the inclusion of kinetic energy, then the dynamic nature of fracture dominates the analysis. For a crack that is already propagating, the inertial effects are important when the crack tip speed is small compared with the stress wave velocities. This fact has been realized in the theory of fracture mechanics under the name of dynamic fracture and peridynamic. In essence, peridynamic replaces the partial differential equations of classic continuum theories with integro-differential equations as a tool to avoid singularities arising from the fact that partial derivatives do not exist on crack surfaces and other singularities. A brief overview of fracture dynamics and peridynamics together with damage mechanisms in composite structures is presented. The limitations of fracture mechanics criteria are also discussed. Life assessment of ship structures depends on the failure modes and the probabilistic description of failure, which are addressed in Part II. Life assessment of ship structures depends on the failure modes and the probabilistic description of failure. In view of structural parameter uncertainties, probabilistic analysis requires the use of reliability methods for assessing fatigue life by considering the crack propagation process and the first passage problem, which measures the probability of the exit time from a safe operating regime. The main results reported in the literature pertaining to ship structural damage assessments resulting from to slamming loads, liquid sloshing impact loads of liquefied natural gas in ship tankers, and ship grounding accidents, an...

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The merging of fatigue and fracture mechanics concepts: a historical perspective

Cited by 145 publications

References 6 publications

The influence of cross‐sectional thickness on fatigue crack growth

The influence of cross‐sectional thickness on fatigue crack growth

Closure of plane‐strain cracks under large‐scale yielding conditions

Overview of Structural Life Assessment and Reliability, Part I: Basic Ingredients of Fracture Mechanics

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