Quasi-Static Simulation of Crack Growth in Elastic Materials Considering Internal Boundaries and Interfaces

This work presents numerical methods used for predicting crack paths in technicalstructures based on the theory of linear elastic fracture mechanics. The FE-method is usedin combination with an efficient remeshing algorithm to simulate crack growth. A post pro-cessor providing loading parameters such as the J-integral and stress intensity factors (SIF) ispresented. Path-independent contour integrals are used to avoid special requirements concern-ing crack tip meshing and to enable efficient calculations for domains including interfaces andinternal boundaries. In particular, the interaction of cracks and internal boundaries and inter-faces is investigated. The simulation combines crack propagation within elastic bodies and atbi-material interfaces. The latter is based on a cohesive zone model. The presented numericalresults of crack paths are verified by experiments.

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Comparison of cohesive zone model and linear elastic fracture mechanics for a mode I crack near a compliant/stiff interface

Engineering Fracture Mechanics ◽

10.1016/j.engfracmech.2010.09.009 ◽

2010 ◽

Vol 77 (17) ◽

pp. 3408-3417 ◽

Cited By ~ 9

Author(s):

Chang-Rong Chen ◽

Yiu-Wing Mai

Keyword(s):

Fracture Mechanics ◽

Cohesive Zone ◽

Cohesive Zone Model ◽

Linear Elastic Fracture Mechanics ◽

Mode I ◽

Zone Model ◽

Mode I Crack ◽

Linear Elastic ◽

Elastic Fracture

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Influence of the Interface and Residual Stresses on the Apparent Fracture Toughness of Layered Ceramic Composites Based on Alumina-Zirconia

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.606.209 ◽

2014 ◽

Vol 606 ◽

pp. 209-212

Author(s):

Luboš Náhlík ◽

Bohuslav Máša ◽

Pavel Hutař

Keyword(s):

Residual Stresses ◽

Crack Propagation ◽

Ceramic Composites ◽

Layered Composites ◽

Material Interfaces ◽

Linear Elastic ◽

Apparent Fracture Toughness ◽

Elastic Fracture ◽

Layered Ceramic ◽

Good Agreement

This paper deals with the fracture behaviour of layered ceramic composite with residual stresses. The main goal is to investigate the effect of residual stresses and material interfaces on crack propagation by more complex 3D finite element models. The crack behaviour was described by analytical procedures based on linear elastic fracture mechanics (LEFM) and generalized LEFM. The influence of laminate composition with residual stresses on critical values for crack propagation through the laminate interfaces was also determined. Good agreement has been found to exist between numerical results and experimental data. The results obtained can be used for a design of new layered composites with improved resistance against crack propagation.

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Handling Uncertainty in the Remnant Fatigue Life Assessment of Offshore Process Pipework

Volume 14: Emerging Technologies; Materials: Genetics to Structures; Safety Engineering and Risk Analysis ◽

10.1115/imece2016-65504 ◽

2016 ◽

Cited By ~ 2

Author(s):

Arvind Keprate ◽

R. M. Chandima Ratnayake

Keyword(s):

Fatigue Life ◽

Crack Growth ◽

Life Assessment ◽

Assessment Process ◽

Linear Elastic ◽

Fatigue Life Assessment ◽

Process Piping ◽

Growth Laws ◽

Elastic Fracture ◽

Offshore Industry

A typical procedure for a remnant fatigue life (RFL) assessment is stated in the BS-7910 standard. The aforementioned standard provides two different methodologies for estimating RFL; these are: the S-N curve approach and the crack growth laws (i.e. using Linear Elastic Fracture Mechanics (LEFM) principles) approach. Due to its higher accuracy, the latter approach is more commonly used for RFL assessment in the offshore industry. Nevertheless, accurate prediction of RFL using the deterministic LEFM approach (stated in BS-7910) is a challenging task, as RFL prediction is afflicted with a high number of uncertainties. Furthermore, BS-7910 does not provide any recommendation in regard to handling the uncertainty in the deterministic RFL assessment process. The most common way of dealing with the aforementioned uncertainty is to employ Probabilistic Crack Growth (PCG) models for estimating the RFL. This manuscript explains the procedure for addressing the uncertainty in the RFL assessment of process piping with the help of a numerical example. The numerically obtained RFL estimate is used to demonstrate a calculation of inspection interval.

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Modeling of Crack Growth in Thin Sheet Aluminum

10.1115/imece1999-0612 ◽

1999 ◽

Author(s):

T. Siegmund ◽

W. Brocks ◽

J. Heerens ◽

G. Tempus ◽

W. Zink

Keyword(s):

Crack Growth ◽

Cohesive Energy ◽

Cohesive Zone Model ◽

Plastic Material ◽

Thin Sheet ◽

High Strength ◽

Cohesive Strength ◽

Zone Model ◽

Additional Material ◽

Center Crack

Abstract The present study reports on the application of a cohesive zone model to the analyses of crack growth in thin sheet specimen of a high strength aluminum alloy. In addition to the elastic-plastic material properties, the two parameters cohesive strength and cohesive energy describe material separation. For the sheet specimen under investigation the cohesive energy is determined via a numerical-experimental approach using tests on notched tensile specimens as well as a damage indicator. The cohesive energy is found to be close to the corresponding value of plane strain fracture toughness. The cohesive strength is approximately twice the yield strength. With these two additional material parameters being determined crack growth experiments in center crack panels are analyzed. Good agreement with experimental records is found. Finally the applicability of the model to study complex crack configurations as in multi-site damaged specimens is demonstrated.

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