3D finite element computation of strain energy release rate using different displacement and stress fields

Abstract This paper utilizes an automated process to simplify the calculation of the strain energy release rate (SERR) during the crack propagation. The convergence of a finite element solution is achieved by adaptive re-meshing scheme with an error estimator of the linear strain triangular (LST) elements. As the desired mesh density is achieved, computation of the SERR using virtual crack closure technique (VCCT) can be obtained by using the static condensation scheme without re-analyzing the finite element models. Thus, the amount of computational and modeling time can be significantly reduced in the analysis of the crack propagation.

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Higher-Order Beam Theories for Mode II Fracture of Unidirectional Composites

Journal of Applied Mechanics ◽

10.1115/1.1607357 ◽

2003 ◽

Vol 70 (6) ◽

pp. 840-852 ◽

Cited By ~ 6

Author(s):

D. V. T. G. Pavan Kumar ◽

B. K. Raghu Prasad

Keyword(s):

Finite Element ◽

Energy Release Rate ◽

Release Rate ◽

Strain Energy ◽

Strain Energy Release Rate ◽

Beam Theory ◽

Strain Energy Release ◽

Mode Ii ◽

Third Order ◽

Beam Theories

Mathematical models, for the stress analyses of unidirectional end notch flexure and end notch cantilever specimens using classical beam theory, first, second, and third-order shear deformation beam theories, have been developed to determine the interlaminar fracture toughness of unidirectional composites in mode II. In the present study, appropriate matching conditions, in terms of generalized displacements and stress resultants, have been derived and applied at the crack tip by enforcing the displacement continuity at the crack tip in conjunction with the variational equation. Strain energy release rate has been calculated using compliance approach. The compliance and strain energy release rate obtained from present formulations have been compared with the existing experimental, analytical, and finite element results and found that results from third-order shear deformation beam theory are in close agreement with the existing experimental and finite element results.

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Analysis of Mixed Mode I/II/III Fracture in Foam Core Sandwich Structures Using Imposed Displacement Split Cantilever Beams

Journal of Theoretical and Applied Mechanics ◽

10.1515/jtam-2015-0018 ◽

2015 ◽

Vol 45 (3) ◽

pp. 69-82

Author(s):

V. Rizov

Keyword(s):

Finite Element ◽

Energy Release Rate ◽

Energy Release ◽

Release Rate ◽

Mixed Mode ◽

Strain Energy ◽

Strain Energy Release Rate ◽

Strain Energy Release ◽

Mode I ◽

Foam Core

Abstract Static fracture in foam core sandwich structures under mixed mode I/II/III loading conditions was studied theoretically. In order to generate such loading conditions, a thread guide was used to impose in- plane displacements of the lower crack arm of a sandwich Split Cantilever Beam (SCB). The upper crack arm was loaded by a transverse force. A three-dimensional finite element model of the imposed displacement sandwich SCB configuration was developed. The fracture was studied applying the concepts of linear-elastic fracture mechanics. The strain energy release rate mode components distribution along the crack front was analyzed using the virtual crack closure technique. The influence of the imposed displacement magnitude and the crack length on the fracture was evaluated. The effect of the sandwich core material on the mixed-mode I/II/III fracture was studied. For this purpose, finite element simulations were carried-out assuming that the core is made by different rigid cellular foams. It was found that the strain energy release rate decreases when the foam density increases.

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Computation of mode I strain energy release rate of symmetrical and asymmetrical sandwich structures using mixed finite element

Frattura ed Integrità Strutturale ◽

10.3221/igf-esis.56.19 ◽

2021 ◽

Vol 15 (56) ◽

pp. 229-239

Author(s):

Amina Mohamed Ben Ali ◽

Salah Bouziane ◽

Hamoudi Bouzerd

Keyword(s):

Finite Element ◽

Energy Release Rate ◽

Energy Release ◽

Release Rate ◽

Strain Energy ◽

Strain Energy Release Rate ◽

Double Cantilever Beam ◽

Mixed Finite Element ◽

Strain Energy Release ◽

Mode I

The use of composite materials is on the rise in different engineering fields, the main advantage of these materials for the aerospace industry is their low weight for excellent mechanical qualities. The analysis of failure modes, such as delamination, of these materials has received great attention from researchers. This paper proposes a method to evaluate the mode I Strain Energy Release Rate (SERR) of sandwich structures. This method associated a two-dimensional mixed finite element with virtual crack extension technique for the analysis of interfacial delamination of sandwich beams. A symmetrical Double Cantilever Beam (DCB) and asymmetrical Double Cantilever Beam (UDCB) have been analyzed in this study. The comparison of the results obtained by this method and those found in the literature shows efficiency and good precision for the calculation of Strain Energy Release Rate (SERR).

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Energy method for the calculation of the energy release rate of delamination in composite beams

Journal of Composite Materials ◽

10.1177/0021998318785952 ◽

2018 ◽

Vol 53 (4) ◽

pp. 425-443 ◽

Cited By ~ 1

Author(s):

Weiling Zheng ◽

Christos Kassapoglou

Keyword(s):

Finite Element ◽

Energy Release Rate ◽

Energy Release ◽

Release Rate ◽

Energy Method ◽

Strain Energy ◽

Strain Energy Release Rate ◽

Crack Tip ◽

Strain Energy Release ◽

Small Cracks

An energy method based on beam theory is proposed to determine the strain energy release rate of an existing crack in composite laminates. The developed analytical method was implemented in isotropic materials, and the obtained strain energy release rate of a crack was validated by reference results and finite element solutions. The general behavior of crack growth on the left or right crack tip was evaluated, and basic trends leading to crack propagation to one side of the crack were established. A correction factor was introduced to improve the accuracy of the strain energy release rate for small cracks. The singularity at the crack tip caused by dissimilar materials was investigated and was found that the inclusion of the singularity effect could increase the accuracy for small cracks. The calculated strain energy release rate of a crack in a composite beam has been verified by comparing with a finite element model.

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Comparative Analysis by the Displacement-Discontinuity Method of Two Energy Criteria of Fracture

Journal of Applied Mechanics ◽

10.1115/1.3424554 ◽

1979 ◽

Vol 46 (2) ◽

pp. 349-355 ◽

Cited By ~ 22

Author(s):

F. H. Cornet

Keyword(s):

Energy Release Rate ◽

Energy Release ◽

Release Rate ◽

Strain Energy ◽

Strain Energy Release Rate ◽

Strain Energy Release ◽

Displacement Discontinuity ◽

Stress Fields ◽

Maximum Strain ◽

Density Factor

This paper discusses the applicability of the displacement-discontinuity technique to crack propagation analysis for plane strain conditions. Results derived from the maximum strain-energy release-rate hypothesis are compared to those obtained with the critical strain-energy-density-factor theory. It is shown that for tensile stress fields both theories give similar results but that they differ for compressive stress fields. Experimental results are more in support of the maximum strain-energy release-rate model.

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