Prediction of Energy Release Rate for Edge Delamination Using a Crack Tip Element Approach

2009 ◽  
pp. 155-155-21 ◽  
Author(s):  
BD Davidson
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Crack Tip ◽  
Element Approach ◽  
Crack Tip Element ◽  
Edge Delamination

An Analytical Crack-Tip Element for Layered Elastic Structures

1995 ◽  
Vol 62 (2) ◽  
pp. 294-305 ◽  
Author(s):  
B. D. Davidson ◽  
Hurang Hu ◽  
R. A. Schapery
Keyword(s):  
Total Energy ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Plate Theory ◽  
Crack Tip ◽  
Total Energy Release ◽  
Linear Elastic ◽  
Crack Tip Element ◽  
Total Energy Release Rate

A previously developed linear elastic crack-tip element analysis is reviewed briefly, and then extended and refined for practical applications. The element provides analytical expressions for total energy release rate and mode mix in terms of plate theory force and moment resultants near the crack tip. The element may be used for cracks within or between homogeneous isotropic or orthotropic layers, as well as for delamination of laminated composites. Classical plate theory is used to derive the equations for total energy release rate and mode mix; a “mode mix parameter,” Ω, as obtained from a separate continuum analysis is necessary to complete the mode mix decomposition. This parameter depends upon the elastic and geometrical properties of the materials above and below the crack plane, but not on the loading. A relatively simple finite element technique for determining the mode-mix parameter is presented and convergence in terms of mesh refinement is studied. Specific values of Ω are also presented for a large number of cases. For those interfaces where a linear elastic solution predicts an oscillatory singularity, an approach is described which allows a unique, physically meaningful value of fracture mode ratio to be defined. This approach is shown to provide predictions of crack growth between dissimilar homogeneous materials that are equivalent to those obtained from the oscillatory field solution. Application of the approach to delamination in fiber-reinforced laminated composites is also discussed.

The Edge Delamination Test: Measuring the Critical Adhesion Energy of Thin-Film Coatings, Part II: Mode Mixity & Application

1994 ◽  
Vol 338 ◽  
Author(s):  
Edward O. Shaffer ◽  
Scott A. Sikorski ◽  
Frederick J. McGarry
Keyword(s):  
Thin Film ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Mode I ◽  
Rigid Substrate ◽  
Edge Delamination

ABSTRACTThe edge delamination test (EDT) is being developed to measure the critical energy required to cause a thin film, under biaxial tensile stress, to debond from a rigid substrate[1]. The test uses circular features etched through biaxially stressed films adhered to a rigid substrate. If the stress is large enough, a stable debond ring grows radially about the feature. We use a finite element analysis to model the test, solving for the applied strain energy release rate as a function of crack length, feature hole radius and other geometrical parameters. The model identifies both mode I and mode II components of the strain energy release rate, and agrees with previous analytical solutions for the total debond energy. However, the model predicts, with a very refined mesh at the crack tip, the fracture process is pure mode I. To explore this result, critical strain energy release rates from the EDT and the island blister test (IBT) are compared. This agreement supports the model prediction that the failure process in the EDT is modeI peeling.

scholarly journals Crack Growth and Energy Release Rate for an Angled Crack under Mixed Mode Loading

2020 ◽  
Vol 10 (12) ◽  
pp. 4227
Author(s):  
Yali Yang ◽  
Seok Jae Chu ◽  
Wei song Huang ◽  
Hao Chen
Keyword(s):  
Energy Release Rate ◽  
Numerical Method ◽  
Energy Release ◽  
Release Rate ◽  
Mixed Mode ◽  
Crack Tip ◽  
Theoretical Expression ◽  
Propagation Mechanism ◽  
Mode I ◽  
Theoretical Derivation

The evaluation of energy release rate with angle is still a challenging task in metal crack propagation analysis, especially for the mixed Mode I-II-III loading situation. In this paper, the energy release rate associated with stress intensity factors at an arbitrary angle under mixed mode loadings has been investigated using both a numerical method and theoretical derivation. A relatively simple and precise numerical method was established through a series of spatial-inclined ellipses in Mode I-II and ellipsoids in Mode I-II-III, with different propagation angles computed from simulation. Meanwhile, a theoretical expression of the energy release rate with angle for a crack tip under a I-II-III mixed mode crack was deduced based on the propagation mechanism of the crack tip under the influence of a stress field. It is confirmed that the theoretical expression deduced could provide results as accurately as the present numerical method. The present results were confirmed to be effective and accurate by comparison with experimental data and other literature.

On the Effect of Latent Heat on the Fracture Toughness of Pseudoelastic Shape Memory Alloys

2014 ◽  
Vol 81 (10) ◽  
Author(s):  
Theocharis Baxevanis ◽  
Chad M. Landis ◽  
Dimitris C. Lagoudas
Keyword(s):  
Fracture Toughness ◽  
Shape Memory Alloys ◽  
Energy Release Rate ◽  
Shape Memory ◽  
Energy Release ◽  
Latent Heat ◽  
Release Rate ◽  
Crack Tip ◽  
Thermomechanical Coupling ◽  
Adiabatic Conditions

A finite element analysis of steady-state crack growth in pseudoelastic shape memory alloys under the assumption of adiabatic conditions is carried out for plane strain, mode I loading. The crack is assumed to propagate at a critical level of the crack-tip energy release rate and the fracture toughness is obtained as the ratio of the far-field applied energy release rate to the crack-tip critical value. Results related to the influence of latent heat on the near-tip stress field and fracture toughness are presented for a range of parameters related to thermomechanical coupling. The levels of fracture toughness enhancement, associated with the energy dissipated by the transformed material in the wake of the growing crack, are found to be lower under adiabatic conditions than under isothermal conditions [Baxevanis et al., 2014, J. Appl. Mech., 81, 041005]. Given that in real applications of shape memory alloy (SMA) components the processes are usually not adiabatic, which is the case with the lowest energy dissipation during a cyclic loading–unloading process (hysteresis), it is expected that the actual level of transformation toughening would be higher than the one corresponding to the adiabatic case.

On Conservative CTOD Estimation Using Far Crack Deformation Field

2013 ◽  
Author(s):  
Piotr Bednarz ◽  
Jaroslaw Szwedowicz
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Crack Tip ◽  
Material Behavior ◽  
Deformation Field ◽  
Nonlinear Material ◽  
Small Scale ◽  
Engineering Practice ◽  
Nonlinear Energy

In general engineering practice, crack tip opening displacement (CTOD) is very convenient approach for prediction of the components fracture mechanics (FM) lifetime. FM lifetime calculations are defined very well in industry and the lifetime prediction methods based on the CTOD resolve linear and nonlinear material behavior for monotonic and cyclic responses. The experiments confirm that under plasticity conditions the crack tip blunts for small scale or large scale yielding while, crack flanks open against each other only under elastic conditions. However, the CTOD application requires a very fine mesh in order to predict a crack tip deformation in reliable manner. Therefore, much more engineering work have to be involved in fine FE modeling. The crack tip flank deformation is crucial parameter responsible for reliable prediction of the nonlinear energy release rate, which is obtained from Hutchinson-Rice-Rosengren solution and the Shih rule. In accordance with design guidelines, the nonlinear energy release rate obtained from the CTOD must be evaluated conservatively to meet demands of RAM (Reliability, Availability and Maintainability). By using far crack deformation field, the paper proposes an engineering approach, which predicts the CTOD in a conservative manner under elastic-plastic conditions. This novel method is validated numerically by applying the well-known J-integral approach.

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