scholarly journals On the calculation of energy release rate and mode mixity in delaminated laminated beams

2016 ◽  
Vol 165 ◽  
pp. 114-139 ◽  
Author(s):  
Paolo S. Valvo
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Mode Mixity ◽  
Laminated Beams

scholarly journals Shear and foundation effects on crack root rotation and mode-mixity in moment- and force-loaded single cantilever beam sandwich specimen

2018 ◽  
Vol 52 (18) ◽  
pp. 2537-2547 ◽  
Author(s):  
Vishnu Saseendran ◽  
Leif A Carlsson ◽  
Christian Berggreen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Cantilever Beam ◽  
Release Rate ◽  
Beam Specimen ◽  
Mode Mixity ◽  
Element Analysis ◽  
Fracture Specimens

Foundation effects play a crucial role in sandwich fracture specimens with a soft core. Accurate estimation of deformation characteristics at the crack front is vital in understanding compliance, energy release rate and mode-mixity in fracture test specimens. Beam on elastic foundation analysis of moment- and force-loaded single cantilever beam sandwich fracture specimens is presented here. In addition, finite element analysis of the single cantilever beam specimen is conducted to determine displacements, rotations, energy release rate and mode-mixity. Based on finite element analysis, a foundation modulus is proposed that closely agrees with the numerical compliance and energy release rate results for all cases considered. An analytical expression for crack root rotation of the loaded upper face sheet provides consistent results for both loading configurations. For the force-loaded single cantilever beam specimen (in contrast to the moment-loaded case), it was found that the crack length normalized energy release rate and the mode-mixity phase angle increase strongly as the crack length decreases, a result of increased dominance of shear loading.

Failure Prediction of Graphite/Epoxy Laminates With Induced Intermittent Surge in Applied Load During Fatigue

2001 ◽  
Author(s):  
Diwakar N. Kedlaya ◽  
Assimina A. Pelegri
Keyword(s):  
Numerical Simulation ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Composite Laminates ◽  
Damage Accumulation ◽  
Applied Load ◽  
Damage Growth ◽  
Mode Mixity ◽  
Accumulation Of Damage

Abstract An analytical model, backed by numerical simulation, describing the behavior of the energy release rate of composite laminates subjected to fatigue overloads is presented. The model establishes that accumulation of damage due to intermittent surge in applied load reduces the energy release rate, G, of the material. Thus, in the case of cyclic loading with overloads, it is essential to model the failure using a damage growth law that incorporates the damage accumulation due to the overloads. The results obtained in this study, have no restrictive assumptions regarding the specimen or the delamination thickness, T and h respectively, and are presented over varying mode-mixity and h/T ratios.

scholarly journals Elliptical adhesive contact under biaxial stretching

2020 ◽  
Vol 476 (2233) ◽  
pp. 20190507 ◽  
Author(s):  
I. Argatov ◽  
A. Papangelo ◽  
M. Ciavarella
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Cell Mechanics ◽  
Weak Coupling ◽  
Adhesive Contact ◽  
Approximate Model ◽  
Mode Mixity ◽  
Elastic Substrate ◽  
Biaxial Stretching

Adhesive contact of the Hertzian indenter with an incompressible elastic substrate bi-directionally stretched along the indenter principal planes of curvature is considered in the Johnson–Kendall–Roberts theoretical framework. An approximate model is constructed by examining energy release rate conditions only on the edges of the minor and major axes of the contact ellipse. The effect of weak coupling between fracture modes I and II is introduced using a phenomenological mode-mixity function. This study was motivated by the need to model a passive–adhesive mechanism in cell mechanics on stretchable substrates.

Stress Intensity Factors for Interfacial Cracks in Thick Thermal Barrier Coatings

1998 ◽  
Author(s):  
C. Bjerken ◽  
C. Persson
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Thermal Barrier ◽  
Intensity Factors ◽  
Mode Mixity ◽  
Release Rates ◽  
Edge Angle ◽  
Interfacial Cracks ◽  
Energy Release Rates

Abstract A straight-forward method for calculating the stress intensity factors (or the energy release rate and mode mixity) for interfacial cracks in bi-materials has been developed. An existing method for homogeneous materials, based on the computation of the energy release rate from the nodal forces and displacements given by a finite element analysis, was modified to include the mismatch in material properties. Thick thermal barrier coatings usually fail as a result of cracking near the interface. The influence of the thickness and the edge angle of the coating on the energy release rate and mode mixity for a small edge crack at the interface of a TBC system subjected to thermal loading was investigated. It was established that the high energy release rates obtained for thick coatings can be reduced by decreasing the edge angle of the coating. Additionally a comparison with energy release rates given by J-integral computations has been done.

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