Frictional Effects in the Buckling Delamination of a Compressed Thin Film and Implications for Interfacial Fracture

1991 ◽  
Vol 239 ◽  
Author(s):  
R. G. Stringfellow ◽  
L. B. Freund
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Coulomb Friction ◽  
Interfacial Friction ◽  
Frictional Interaction ◽  
Post Buckling ◽  
Buckling Delamination ◽  
Delamination Front ◽  
Frictional Effects

ABSTRACTAs a film in residual compression delaminates from a substrate, the post-buckling response of the film tends to drive it into the substrate in the region directly behind the delamination front. We consider the process of frictional interaction between the film and the substrate during the delamination process in order to assess the effect of Coulomb friction on the energy release rate, G, driving the delamination. For the case in which the film and the substrate have identical elastic properties, we derive a singular integral equation to determine the relative sliding displacement of the opposing faces of the interface. Using an analytical model, we find that G decreases by about 35% when the coefficient of interfacial friction is equal to one. Using finite element methods, we then investigate the effects of compliance differences between the film and the substrate. We find that, when the film is more compliant than the substrate, frictional interaction is enhanced and the calculated energy release rate decreases substantially. We conclude that frictional effects can account for a significant portion of the energy dissipation during the delamination process, and thus can play an important role in the observed arrest of spreading delaminations.

Calculation of total energy release rate in post-local buckling delamination of composite laminates

2016 ◽  
Vol 51 (5) ◽  
pp. 623-635 ◽  
Author(s):  
M Naghinejad ◽  
H R Ovesy
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Shear Deformation ◽  
Release Rate ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Higher Order ◽  
Buckling Load ◽  
Post Buckling ◽  
Total Energy Release Rate

In the present article, the variational energy principle is used to derive the expression for energy release rate in buckled composite laminate containing through-the-width delamination, subjected to in-plane strains. Boundary conditions are clamped at both edges. Buckling and post-buckling solutions are obtained and expressions for critical buckling load and post-buckling deflection have been developed. A through-the-width delamination model has been considered and formulations are based on higher order shear deformation theory. The effects of considering the higher order shear deformation theory on equivalent bending rigidity, buckling load, and energy release rate have been investigated. Finally, the results of current study have been compared with the results of finite element method analysis by Abaqus/CAE and those available in the literature.

The Initial Post-buckling and Growth Behavior of Internal Delaminations in Composite Plates

1993 ◽  
Vol 60 (4) ◽  
pp. 903-910 ◽  
Author(s):  
G. A. Kardomateas
Keyword(s):  
Energy Release Rate ◽  
Closed Form ◽  
Energy Release ◽  
Release Rate ◽  
Plate Thickness ◽  
Composite Plates ◽  
Growth Behavior ◽  
Mode I ◽  
Perturbation Procedure ◽  
Post Buckling

The initial post-buckling and growth behavior of delaminations in plates is studied by a perturbation procedure. In this work, no restrictive assumptions regarding the delamination thickness and plate length are made, i.e., the usual thin film assumptions are relaxed. The perturbation procedure is based on an asymptotic expansion of the load and deformation quantities in terms of the distortion parameter of the delaminated layer, the latter being considered a compressive elastica. Closed-form solutions for the load and midpoint delamination deflection versus applied compressive displacement during the initial post-buckling phase are derived. Moreover, closed-form expressions for the energy release rate and the mixity ratio (i.e., Mode II versus Mode I) at the delamination tip are produced. A higher Mode I component is found to be present during the initial post-buckling phase for delaminations of increasing ratio of delamination thickness over plate thickness, h/T (i.e., delaminations further away from the surface). Moreover, the-energy release rate corresponding to the same applied strain is larger for a higher h/T ratio. The reduced growth resistance of these configurations is verified by experimental results on unidirectional composite specimens with internal delaminations.

Energy Release Rate of Delaminated Piezoelectric Shell Subjected to Electro-Thermo-Mechanical Loadings

2015 ◽  
Vol 751 ◽  
pp. 118-123
Author(s):  
Jin Hua Yang ◽  
Peng Jun Zhang ◽  
Chang Zhao Qian
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Moving Boundary ◽  
Mechanical Load ◽  
Structural Failure ◽  
Delamination Growth ◽  
Griffith Criterion ◽  
Delamination Front ◽  
Piezoelectric Shell

The delamination growth may occur in delaminated piezoelectric shell subjected to external load and it will further cause structural failure. Based on the variational principle of moving boundary and considering the contact effect between delamination regions, in this paper, the nonlinear governing equations for the delaminated piezoelectric shell under electro-thermo-mechanical loadings are derived, and the corresponding boundary and matching conditions are given. At the same time, according to the Griffith criterion, the formulas of energy release rate along the delamination front are obtained and the delamination growth is studied. In the numerical calculation, the energy release rate and delamination growth of axisymmetrical piezoelectric cylindrical shell are analyzed, and the effects of voltage, temperature and humidity, mechanical load, delamination length and depth on delamination growth are discussed.

Finite Element Data Reduction Based Energy Release Rate for Delamination Tests

2012 ◽  
Vol 498 ◽  
pp. 67-78
Author(s):  
S. Choukri ◽  
Moussa Karama
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Data Reduction ◽  
Test Procedure ◽  
Laminated Composite ◽  
Composite Plates ◽  
Direct Energy ◽  
Delamination Front

This paper deals with the advantages of the finite element modeling and design, especially, of delamination test coupons involved in fracture analysis of laminated composite plates. This is shown through two relevant aspects in delamination toughness measuring, say: data reduction and Iso-G delamination front design. Many experimental data reductions are based on beam theories and thus assumes straight delamination front during propagation, which is not true when investigating laminates with general anisotropy. Another aspect is also emphasized, and concern test procedure simplification to avoid displacement measurements. This is done through a direct energy release rate calculations via the crack closure integral method.

Calculating Energy Release Rate as a Function of Crack Length Using a Multiple-Step Crack Closure Technique in Tire Finite Element Models

2018 ◽  
Vol 46 (3) ◽  
pp. 130-152
Author(s):  
Dennis S. Kelliher
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Crack Length ◽  
Energy Release ◽  
Crack Closure ◽  
Release Rate ◽  
Fatigue Behavior ◽  
Three Dimensions ◽  
Quantitative Prediction ◽  
Closure Technique

ABSTRACT When performing predictive durability analyses on tires using finite element methods, it is generally recognized that energy release rate (ERR) is the best measure by which to characterize the fatigue behavior of rubber. By addressing actual cracks in a simulation geometry, ERR provides a more appropriate durability criterion than the strain energy density (SED) of geometries without cracks. If determined as a function of crack length and loading history, and augmented with material crack growth properties, ERR allows for a quantitative prediction of fatigue life. Complications arise, however, from extra steps required to implement the calculation of ERR within the analysis process. This article presents an overview and some details of a method to perform such analyses. The method involves a preprocessing step that automates the creation of a ribbon crack within an axisymmetric-geometry finite element model at a predetermined location. After inflating and expanding to three dimensions to fully load the tire against a surface, full ribbon sections of the crack are then incrementally closed through multiple solution steps, finally achieving complete closure. A postprocessing step is developed to determine ERR as a function of crack length from this enforced crack closure technique. This includes an innovative approach to calculating ERR as the crack length approaches zero.

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