scholarly journals Energy Release Rate Associated with Interfacial Crack Growth of Laminates Including Residual Thermal Stresses: Application of Crack Tip Element Method

2009 ◽  
Vol 35 (3) ◽  
pp. 99-105
Author(s):  
Tomohiro YOKOZEKI
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Thermal Stresses ◽  
Interfacial Crack ◽  
Crack Tip ◽  
Crack Tip Element ◽  
Element Method

Effect of Solvent Diffusion on Crack-Tip Fields and Driving Force for Fracture of Hydrogels

2015 ◽  
Vol 82 (8) ◽  
Author(s):  
Nikolaos Bouklas ◽  
Chad M. Landis ◽  
Rui Huang
Keyword(s):  
Boundary Conditions ◽  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Crack Tip ◽  
Far Field ◽  
Solvent Diffusion ◽  
Effect Of Solvent ◽  
Transient Energy

Hydrogels are used in a variety of applications ranging from tissue engineering to soft robotics. They often undergo large deformation coupled with solvent diffusion, and structural integrity is important when they are used as structural components. This paper presents a thermodynamically consistent method for calculating the transient energy release rate for crack growth in hydrogels based on a modified path-independent J-integral. The transient energy release rate takes into account the effect of solvent diffusion, separating the energy lost in diffusion from the energy available to drive crack growth. Numerical simulations are performed using a nonlinear transient finite element method for center-cracked hydrogel specimens, subject to remote tension under generalized plane strain conditions. The hydrogel specimen is assumed to be either immersed in a solvent or not immersed by imposing different chemical boundary conditions. Sharp crack and rounded notch models are used for small and large far-field strains, respectively. Comparisons to linear elastic fracture mechanics (LEFM) are presented for the crack-tip fields and crack opening profiles in the instantaneous and equilibrium limits. It is found that the stress singularity at the crack tip depends on both the far-field strain and the local solvent diffusion, and the latter evolves with time and depends on the chemical boundary conditions. The transient energy release rate is predicted as a function of time for the two types of boundary conditions with distinct behaviors due to solvent diffusion. Possible scenarios of delayed fracture are discussed based on evolution of the transient energy release rate.

scholarly journals Analytical Energy Release Rate of Interfacial Crack in Composite Laminates

2019 ◽  
Vol 37 (1) ◽  
pp. 137-142
Author(s):  
Weiling Zheng ◽  
Longxi Zheng
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Composite Laminates ◽  
Interfacial Crack ◽  
Crack Tip ◽  
Beam Theory ◽  
Three Point Bending ◽  
The Right

In order to study whether the interfacial crack will grow or not in the composite laminates, the energy release rate of a crack in three-point bending model was obtained by using the Timoshenko beam theory and local generalized forces. The results of energy release rate were validated by the finite element results. The results indicate that the energy release rate of left crack tip is equal to that of the right crack tip when the crack before the crack goes cross the loading point; after the crack goes cross the loading point, the energy release rate of the left crack tip increases and then decreases gradually, while the energy release rate of right crack tip decreases first and increases later; the energy release rate of left crack tip is equal to that of the right crack tip again when the crack is symmetric with the loading point.

scholarly journals Analytical Fracture Mechanics Analysis of the Pull-Out Test Including the Effects of Friction and Thermal Stresses

2000 ◽  
Vol 9 (6) ◽  
pp. 096369350000900 ◽  
Author(s):  
John A. Nairn
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Thermal Stresses ◽  
Interfacial Crack ◽  
Single Fibre ◽  
Finite Elements Analysis ◽  
Accurate Analysis ◽  
Pull Out ◽  
Microbond Test

The energy release rate for propagation of a debond in a single-fibre pull out test was derived analytically. The key finding was that an accurate analysis can be derived by a global energy analysis that includes effects of residual stresses and interfacial friction but does not need to include the details of the stress state at the interfacial crack tip. By comparison to finite elements analysis, it was verified that the analytical results are very accurate provided the debond tip is not too close to either end of the specimen. By casting the results in terms of net-specimen stress, it was possible to derive a general energy release rate result that applies to both the pull-out test and the related microbond test. The energy release rate expressions can be used to determine interfacial fracture toughness from single-fibre pull-out tests or microbond tests.

A new Interface Element Method on Computation of the Interface Crack Propagation Energy Release Rate

2012 ◽  
Vol 204-208 ◽  
pp. 4573-4577
Author(s):  
Zhi Peng Zhong ◽  
Shui Wan ◽  
Lin Yun Zhou
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Crack Tip ◽  
Strain Energy Release ◽  
Interface Element ◽  
Energy Release Rates ◽  
Internal Forces ◽  
Strain Energy Release Rates ◽  
Element Method

A new interface element method was proposed to calculate the strain energy release rates(SERR) based on the virtual crack closure technique (VCCT). A Lagrange multiplier was introduced between the node pair at crack tip to obtain the internal forces. Then from the VCCT, the SERR was solved by using the forces and displacements near the crack tip. Examples for stationary cracks under the two typical cases are given. Meanwhile, the relationship curves between crack energy release rate and the length of crack, plate depths were plotted respectively.The example shows that the interface element used to calculate the SERR is simple, efficient, and highly accurate in analysis of 2D crack growth problems, and without requiring the special singularity element or collapsed element at crack tip.

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