Numerical simulation of plasticity induced fatigue crack opening and closure for autofrettaged intersecting holes

Herz, Elisabeth; Hertel, Olaf; Vormwald, Michael

doi:10.1016/j.engfracmech.2010.05.011

Cited by 31 publications

(21 citation statements)

References 25 publications

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“…However, two other fields of application are currently under investigation. The first field is the calculation of the endurance limit and the fatigue crack growth life of autofrettaged intersecting holes, which are shown in Figure 5 [21,22]. In the aforementioned references a nodal-release scheme, assuming a straight crack front, was used for that purpose.…”

Section: Discussionmentioning

confidence: 99%

Simulation of fatigue crack growth under consideration of cyclic plasticity

Zerres¹,

Döring

Vormwald

2011

Materialwissenschaft Werkst

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In this paper a procedure to simulate the crack growth under consideration of elastic‐plastic material behavior by means of the finite element method is described. Within this procedure, after each increment of crack advance, the structure is remeshed and the status variables, such as the components of the backstress‐tensor and the plastic strains, are transferred from the old mesh to the new one. Due to mapping of the variables, improper conditions are possibly prevailing at the beginning of the new analysis, which has to be captured by the used material routine. The main focus of this paper is to describe these necessary numerical adjustments.

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Section: Discussionmentioning

confidence: 99%

Simulation of fatigue crack growth under consideration of cyclic plasticity

Zerres¹,

Döring

Vormwald

2011

Materialwissenschaft Werkst

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“…More complex approaches point at identifying effective, i.e. closure-free ranges by finite element based fatigue crack growth simulations [27][28][29][30].…”

Section: Plastic Deformationmentioning

confidence: 99%

Classification of Load Sequence Effects in Metallic Structures

Vormwald

2015

Procedia Engineering

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Due to the summation rule for the relative consumed fatigue life the basic property of linear damage accumulation is the independence of the calculation results from the sequence of occurrence of the cycles. In the physical fatigue damage accumulation the sequence of the occurrence of individual cycles indeed plays an important role. The material and the structure, respectively, have the ability to store information on prior loading histories. A classification of physical phenomena was undertaken. Two main groups of information storage possibilities have been identified: material's plastic deformation and irreversible material separation processes.

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“…1c) disposta simmetricamente rispetto alla bisettrice dell'angolo  formato dall'incrocio dei due assi dei fori. Questa assunzione è in accordo con quanto fatto in [12] dove, oltre ad aver monitorato a posteriori la vera forma della cricca nucleata nel punto di intersezione, è stata proposta tale esemplificazione lineare per agevolare il calcolo dell'allungamento della cricca sotto un carico pulsante. Per rendere di validità generale il calcolo dello SIF e non legato ad uno specifico tipo di carico, si è deciso di utilizzare il metodo delle weight function [13 e 14] assumendo lo sviluppo in serie di Sha e Yang [9] troncato al terzo ordine.…”

Section: Il Metodo Delle Funzioni Peso Per Il Calcolo Dello Sifunclassified

“…(4-6) risulta necessario avere a disposizione i fattori di intensificazione delle tensioni per una cricca di profondità stabilita e tre differenti condizioni di carico. Recenti lavori eseguiti da Herz et al [12] hanno evidenziato che, per D1/D2=1 e =90°, l'andamento dei parametri M2 ed M3 è stato assunto costante lungo la direzione di propagazione della cricca e pari rispettivamente a 3 e -3. In questo preliminare lavoro, si adotterà tale ipotesi esemplificativa, mantenendo costanti M 2 ed M 3 relegando così la variabilita dei parametri M i solo su M 1 .…”

Section: Calcolo Numerico Dello Sif DI Cricche Bidimensionaliunclassified

Mode I Stress Intensity Factors for triangular corner crack nearby intersecting of cylindrical holes

Salvati¹,

Livieri²,

Tovo³

2013

Frattura Ed Integrità Strutturale

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The paper deals with the Stress Intensity Factor assessment of cracks at the intersection of holes loaded by internal pressure. Triangular flaws are considered at the intersection of two holes inside a specific specimen. The research examines the influence of hole diameter ratio D 1 /D 2 and the angle between their axes α. Numerical analysis is performed to determine the Stress Intensity Factors (SIF) of mode I in many different geometric configurations. The actual shape of a real crack nucleated at the intersection of two cylindrical holes is subject to variable internal pressure and is usually geometrically complex. The Stress Intensity Factor changes along the crack contour and the crack shape development is controlled by its local value, e.g. during a fatigue loading. In general, the estimation of the Stress Intensity Factors of cracks with a complex shape is made by means of numerical methods since closed form solutions in literature are limited. However, in order to solve the problem of crack propagation more quickly, in the case of a crack corner at the intersection between two cylindrical holes, we can assume, in agreement with scientific literature, a symmetrical triangular crack shape and the Stress Intensity Factor are only calculated at the middle of the crack. Obviously, this is a strong approximation, but this allows a reduction in the computation effort for crack growth rate assessments and safety evaluation. In this paper, the weight function technique is used by integrating the actual stress field evaluated in the uncracked model. The method of the weight function is of general validity and the weight function is related to the displacement components close to the crack front, as proposed by Bueckner and Rice. From a computational point of view, the use of the three-dimensional weight function is complex and in scientific literature a weight function of general validity is not available. Nevertheless, thanks to the work conducted by Petroski and Achenbach, Shen and Glinka, an efficient generalised weight function has been adopted and then developed by Sha and Yang [9], which considers a series expansion of non-singular terms. In this way, the integration of the weight function, multiplied by a nominal stress, is made along a line and not in a two-dimensional domain. In this preliminary work, according to Herz et al., we consider a weight function with three terms by assuming a priori the coefficients of the second and third non-singular terms. This contribution is essentially an extension of a previous paper by Herz et al. They only considered the case of D 1 /D 2 =1 and =90° (D i are the diameters of the two cylindrical holes and a is the angle between their axis). Here, we extend the analysis to D 1 /D 2 equal to 2, 4 and 8 with an  of 60 and 45 degrees.

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Numerical simulation of plasticity induced fatigue crack opening and closure for autofrettaged intersecting holes

Cited by 31 publications

References 25 publications

Simulation of fatigue crack growth under consideration of cyclic plasticity

Simulation of fatigue crack growth under consideration of cyclic plasticity

Classification of Load Sequence Effects in Metallic Structures

Mode I Stress Intensity Factors for triangular corner crack nearby intersecting of cylindrical holes

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