The Dynamic Energy Release Rate of Delaminations Based on Midlin-Type Nonlinear Plate Theory

1993 ◽  
Vol 60 (4) ◽  
pp. 1046-1047 ◽  
Author(s):  
A. E. Giannakopoulos ◽  
K. -F. Nilsson
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Plate Theory ◽  
Nonlinear Plate ◽  
Dynamic Energy Release Rate

The Dynamic Energy Release Rate for a Steadily Propagating Antiplane Shear Crack in a Linearly Viscoelastic Body

1987 ◽  
Vol 54 (3) ◽  
pp. 635-641 ◽  
Author(s):  
J. R. Walton
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Shear Crack ◽  
Viscoelastic Body ◽  
Antiplane Shear ◽  
Singular Stress ◽  
Crack Face ◽  
Standard Linear Solid ◽  
Dynamic Energy Release Rate

The steady-state propagation of a semi-infinite, antiplane shear crack is reconsidered for a general, infinite, homogeneous and isotropic linearly viscoelastic body. As with an earlier study, the inertial term in the equation of motion is retained and the shear modulus is only assumed to be positive, continuous, decreasing, and convex. A Barenblatt type failure zone is introduced in order to cancel the singular stress, and a numerically convenient expression for the dynamic Energy Release Rate (ERR) is derived for a rather general class of crack face loadings. The ERR is shown to have a complicated dependence on crack speed and material properties with significant qualitative differences between viscoelastic and elastic material. The results are illustrated with numerical calculations for both power-law material and a standard linear solid.

Thickness Effects Are Minor in the Energy-Release Rate Integral for Bent Plates Containing Elliptic Holes or Cracks

1981 ◽  
Vol 48 (2) ◽  
pp. 320-326 ◽  
Author(s):  
J. G. Simmonds ◽  
J. Duva
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Relative Error ◽  
Release Rate ◽  
Plate Theory ◽  
Semimajor Axis ◽  
Elliptic Hole ◽  
Three Dimensional ◽  
Radius Of Curvature ◽  
Classical Plate Theory

The exact value of Sanders’ path-independent, energy-release rate integral I for an infinite, bent elastic slab containing an elliptic hole is shown to be approximated by its value from classical plate theory to within a relative error of O(h/c)F(e), where h is the thickness, c is the semimajor axis of the ellipse, and F is a function of the eccentricity e. This result is based on Golden’veiser’s analysis of three-dimensional edge effects in plates, as developed by van der Heijden. As the elliptic hole approaches a crack, F(e)~In (1−e). However, this limit is physically meaningless, because Golden’veiser’s analysis assumes that h is small compared to the minimum radius of curvature of the ellipse. Using Knowles and Wang’s analysis of the stresses in a cracked plate predicted by Reissner’s theory, we show that the relative error in computing I from classical plate theory is only O(h/c)In(h/c), where c is the semicrack length. Our results suggest that classical plate and shell theories are entirely adequate for predicting crack growth, within the limitations of applying any elastic theory to an inherently inelastic phenomenon.

Prediction of Energy Release Rate for Mixed-Mode Delamination Using Classical Plate Theory

1990 ◽  
Vol 43 (5S) ◽  
pp. S281-S287 ◽  
Author(s):  
R. A. Schapery ◽  
B. D. Davidson
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Mixed Mode ◽  
Plate Theory ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Classical Plate Theory

Prediction of the energy release rate (ERR) and its components for mixed-mode delamination of composite laminates is discussed. A classical plate theory (CPT) version of Irwin’s virtual crack closure method is developed and used for the ERR, first for plane strain and then for three-dimensional deformations. It is shown that CPT does not provide quite enough information to obtain a decomposition of ERR into its opening and shearing mode components. Results from a continuum analysis are needed to complete the decomposition; but analysis of only one loading case is required for two-dimensional and certain three-dimensional problems. In two example problems the finite element method is used with CPT to complete the mode decomposition. Results from CPT and the finite element method are then compared for several cases.

Three Dimensional Analysis and Resulting Design Recommendations for Unidirectional and Multidirectional End-Notched Flexure Tests

1995 ◽  
Vol 29 (16) ◽  
pp. 2108-2133 ◽  
Author(s):  
B. D. Davidson ◽  
R. Kruger ◽  
M. König
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Plate Theory ◽  
Design Procedure ◽  
Local Mode ◽  
Mode Ii ◽  
Mode Iii ◽  
Release Rates ◽  
Energy Release Rates

Results are presented from a theoretical investigation of the effects of stacking sequence on the energy release rate in laminated composite end-notched flexure test specimens. Deflections and energy release rates of unidirectional and multidirectional ENF specimens are obtained by classical laminated plate theory, shear deformable plate theory, and three dimensional finite element analyses. It is shown that the distribution of energy release rate varies across the front of an initially straight delamination. The percentage of mode II and mode III energy release rates for the specimen, as well as the local peak values of the mode II, mode III and total energy release rates that occur at the specimen's free edges are shown to correlate with a nondimensional ratio comprised of the specimen's flexural rigidities. The results of the study are used as a basis for a proposed “ENF test design procedure” that may be used for the determination of appropriate specimen stacking sequences and test geometries for studying delamination growth at interfaces between plies at various orientations. The test design procedure minimizes the contributions to the energy release rate from residual thermal stresses, geometric nonlinearities, local mode II concentrations at the specimen's free edges and local mode III effects.

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