Initiation and Growth of Transverse Cracks and Edge Delamination in Composite Laminates Part 1. An Energy Method

Wang, A.S.D.; Crossman, F. W.

doi:10.1177/002199838001400106

Cited by 248 publications

(56 citation statements)

References 12 publications

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“…The applied K or G is then compared to a mode-dependent critical value of K or G from experiment. The work of Wang and Crossman (1980), O'Brien (1982) and Wang (1982) was some of the earliest to use this type of approach. One advantage of a fracture-based approach is that finite energy release rates result, even for limiting cases where the length of the delamination crack approaches zero.…”

Section: Introductionmentioning

confidence: 99%

Separation of crack extension modes in orthotropic delamination models

Beuth

1996

Int J Fract

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In the analysis of an interface crack between dissimilar elastic materials, the mode of crack extension is typically not unique, due to oscillatory behavior of near-tip stresses and displacements. This behavior currently limits the applicability of interfacial fracture mechanics as a means to predict delamination in layered materials. The Virtual Crack Closure Technique (VCCT) is a method used to extract mode I and mode II energy release rates from numerical fracture solutions. The mode of crack extension extracted from an oscillatory solution using the VCCT is not unique due to the dependence of mode on the virtual crack extension length, A.In this work, a method is presented for using the VCCT to extract A-independent crack extension modes for the case of an interface crack between two in-plane orthotropic materials.The method does not involve altering the analysis to eliminate its oscillatory behavior. Instead, it is argued that physically reasonable, A-independent modes of crack extension can be extracted from oscillatory solutions. Knowledge of near-'tip fields is used to determine the explicit A dependence of energy release rate parameters. Energy release rates are then defined that are separated from the oscillatory dependence on A. A modified VCCT using these energy release rate definitions is applied to results from finite element analyses, showing that A-independent modes of crack extension result. The modified technique has potential as a consistent method for extracting crack extension modes from numerical solutions. The A-independent modes extracted using this technique can also serve as guides for testing .the convergence of finite element models. Direct applications of this work include the analysis of planar composite delamination problems, where plies or debonded laminates are modeled as in-plane orthotropic materials.

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Section: Introductionmentioning

confidence: 99%

Separation of crack extension modes in orthotropic delamination models

Beuth

1996

Int J Fract

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“…Great attention has been given to the problem of free-edge delamination in laminates subjected to in-plane static and fatigue loadings [1][2][3][4], and many people have attempted to measure the fracture toughness with respect to delamination cracks [5][6][7][8][9]. Few attempts have been made, however, to measure the dynamic delamination fracture toughness.…”

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confidence: 99%

Dynamic Delamination Crack Propagation in a Graphite/Epoxy Laminate

Grady

Sun

1986

Composite Materials: Fatigue and Fracture

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Ballistic impact tests of [90/0]5s T-300/934 graphite/epoxy laminates of beam-like dimension with embedded delamination cracks were conducted. High speed photography (16 000 frames/second) was used to record the impact response and subsequent crack propagation. From the photographic data, impact characteristics such as the contact duration and the dynamic response of the impact specimen were measured. In addition, the time of initiation of delamination propagation and measurements of the subsequent delamination length versus time were obtained. By changing the location of the embedded delamination in the specimens relative to the impact point, additional results were obtained on the variation of the threshold impact velocity necessary to cause crack propagation in the different specimen configurations. These data, together with the photographic results, suggest that the mode of crack propagation is dependent on the specimen geometry as well as the loading condition. The time dependent nature of the crack velocity and its variation with impact conditions was investigated. A finite element program was used to calculate the dynamic strain energy release rate before the onset of crack propagation. This strain energy release rate was used to gage the instability of the delamination crack during impact.

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“…In 21 The subscripts 1, 2 and 3 correspond to the longitudinal transverse and thickness directions respectivelv.…”

Section: Four-ply Laminatesmentioning

confidence: 99%