An Application of Finite Element-Based Fracture Mechanics Analysis to Cord-Rubber Structures

1996 ◽  
Vol 24 (3) ◽  
pp. 220-235 ◽  
Author(s):  
T. G. Ebbott
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Fatigue Behavior ◽  
Internal Crack ◽  
Materials Testing ◽  
Element Analysis ◽  
Rate Evaluation

Abstract A finite element-based method to analyze the severity of internal cracks in cord-rubber structures is presented. The method includes materials testing to characterize rubber fatigue behavior, a global-local finite element analysis to provide the detail necessary to model explicitly an internal crack, and use of the J-integral and virtual crack closure techniques for energy release rate evaluation. Analysis of the multiaxial and cyclic fracture situation is carried out by considering the cycle of each mode of fracture separately and then combining the effect of each mode to determine the total effect. Crack growth rates in the structure are assumed to be the same as the crack growth rate in a laboratory specimen at the same level of cyclic energy release rate. Results are presented for a material change in a critical tire region.

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.

Finite Element Modeling for Energy Release Rate in Human Cortical Bone

Volume 2 ◽  
2004 ◽  
Author(s):  
Saiphon Charoenphan ◽  
Apiwon Polchai
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Finite Element Modeling ◽  
Energy Release Rate ◽  
Cortical Bone ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Slow Crack Growth ◽  
Finite Element Models

The energy release rates in human cortical bone are investigated using a hybrid method of experimental and finite element modeling techniques. An explicit finite element analysis was implemented with an energy release rate calculation for evaluating this important fracture property of bones. Comparison of the critical value of the energy release rate, Gc, shows good agreement between the finite element models and analytical solutions. The Gc was found to be approximately 820–1150 J/m2 depending upon the samples. Specimen thickness appears to have little effect on the plane strain condition and pure mode I assumption. Therefore the energy release rate can be regarded as a material constant and geometry independent and can be determined with thinner specimens. In addition, the R curve resulting from the finite element models during slow crack growth shows slight ductility of the bone specimen that indicates an ability to resist crack propagation. Oscillations were found at the onset of the crack growth due to the nodal releasing application in the models. In this study light mass-proportional damping was used to suppress the noises. Although this techniques was found to be efficient for this slow crack growth simulation, other methods to continuously release nodes during the crack growth would be recommended for rapid crack propagation.

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.

The Characterization of Mixed-Mode Energy Release Rates in Orthotropic Materials

1996 ◽  
Vol 210 (1) ◽  
pp. 33-42 ◽  
Author(s):  
C A Walker ◽  
Jamasri
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Mode I ◽  
Mode Ii ◽  
Finite Element Models ◽  
Release Rates ◽  
Energy Release Rates

The aim of this work was to predict, from the material constants, mixed-mode energy release rates in orthotropic materials, in particular the general cases in which the crack is aligned at a random angle to the principal material direction, normal to the plane of orthotropy. Two-dimensional finite element models with various fibre orientations were generated. The finite element models were validated by comparing two sets of contour plots of deformation, one resulting from the finite element analysis and the other from moiré interferograms of the experimental work. On comparison there was shown to be a strict similarity between experimentally determined and computational deformation fields. Variations of the energy release rates were investigated for both rapid and stable crack growth. This was accomplished by generating two-dimensional stable crack growth finite element models. In general, energy release rates were found to be strongly affected by the fibre orientation. An increase of the angle of the crack growth direction caused a decrease of the mode I energy release rate and, by contrast, an increase of the mode II energy release rate, but the mode II energy release rate was always a small fraction of the mode I value. Crack extension caused a gradual increase of the mode I energy release rate both for coplanar and non-coplanar crack growth. However, there was no significant effect found on the mode II energy release rate.

scholarly journals Finite Element Analysis for Interfacial Crack in Piezoelectric Composite under Impact Loading

2012 ◽  
Vol 21 (1) ◽  
pp. 096369351202100
Author(s):  
Liang Wang ◽  
Rui-Xiang Bai ◽  
Hao-Ran Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Impact Loading ◽  
Crack Surface ◽  
Piezoelectric Composite ◽  
Element Analysis ◽  
Piezoelectric Composites

In this paper, a nonlinear finite element analysis of impact interfacial fracture for a piezoelectric composite is provided. The Newmark method was used to solve the dynamics equation. Virtual crack closure technique is to evaluate the energy release rate of crack tip. Contact elements were set up on crack surface and in the area in contact under impact loading to prevent the penetration between PZT and composite. The response curves of the energy release rate are obtained for piezoelectric composites. Numerical results are provided to show the effect of the piezoelectricity, the applied voltage, the stack sequence of composites and the contact of crack surface on the resulting dynamic energy release rate of piezoelectric composites.

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