An invariance property of local energy release rate in a strip saturation model of piezoelectric fracture

1996 ◽  
Vol 79 (2) ◽  
pp. R25-R29 ◽  
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Invariance Property ◽  
Local Energy ◽  
Saturation Model

On the Energy Release Rate of Elliptical Cracks in Anisotropic Elastic Media

2003 ◽  
Vol 19 (1) ◽  
pp. 233-239
Author(s):  
Yibin Xue ◽  
Jianmin Qu
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Opening Displacement ◽  
Release Rate ◽  
Crack Opening ◽  
Average Energy ◽  
Local Energy ◽  
Opening Displacement ◽  
Work Done ◽  
Elliptical Cracks

ABSTRACTThis brief note discusses some issues related to the calculation of energy release rate for elliptical cracks in anisotropic solids. By using the Stroh formalism, analytical expressions of the energy release rate are obtained for elliptical cracks in an unbounded anisotropic solid. Because of material anisotropy and geometric asymmetry of the crack, the local energy release rate varies along the crack front. The average energy release rate can be obtained by integrating the local energy release rate over the entire crack front. On the other hand, the total work done by the crack-surface traction on the entire crack opening displacement can be easily evaluated once the crack opening displacement is known. It is shown that the average energy release rate is equal to the rate of change per unit crack area increment of the work done by the external load on the crack opening displacement.

scholarly journals The surface-forming energy release rate versus the local energy release rate

2017 ◽  
Vol 175 ◽  
pp. 86-100 ◽  
Author(s):  
Si Xiao ◽  
He-ling Wang ◽  
Bin Liu ◽  
Keh-Chih Hwang
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Local Energy ◽  
Rate Versus

scholarly journals A critical local energy release rate criterion for fatigue fracture of elastomers

2011 ◽  
Vol 49 (21) ◽  
pp. 1518-1524 ◽  
Author(s):  
Samy Mzabi ◽  
Daniel Berghezan ◽  
Stéphane Roux ◽  
Francois Hild ◽  
Costantino Creton
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Fatigue Fracture ◽  
Release Rate ◽  
Local Energy ◽  
Energy Release Rate Criterion ◽  
Rate Criterion

Research on Optimization of Excavating Seguence for Dawangou Tunnel

2013 ◽  
Vol 353-356 ◽  
pp. 3703-3706
Author(s):  
Chang Yu Jin ◽  
Pan Pan Zhao ◽  
Chun Fu Xiang ◽  
Zi Feng Xia ◽  
Long Bin Dong ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Numerical Analysis ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Brittle Failure ◽  
Hard Rock ◽  
Local Energy ◽  
Change Trend

In response to the limitation of conventional index for stability and optimal design of underground rock mass engineering. The new evaluating indicator, local energy release rate, which can analysis the energy release intensity in the process of the brittle failure of hard rock is used in numerical analysis. Numerical simulation of construction sequence was studied for Dawangou tunnel using energy release rate index and a new constitutive model reflecting the brittle failure of hard rock. Based on the change trend of energy release rate, rock displacement and plastic zone, an optimization excavation is suggested. The optimal excavating sequence could serve as reference in the design and construction.

Adhesive Strength of Atherosclerotic Plaques Depends on Collagen Content

2012 ◽  
Author(s):  
Ying Wang ◽  
John A. Johnson ◽  
Abigail Fulp ◽  
Michael A. Sutton ◽  
Susan M. Lessner
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Atherosclerotic Plaque ◽  
Release Rate ◽  
Adhesive Strength ◽  
Plaque Rupture ◽  
Mechanical Test ◽  
Coronary Thrombosis ◽  
Local Energy ◽  
Plaque Composition

Atherosclerotic plaque rupture is a major cause of myocardial infarction, coronary thrombosis and stroke. In a previous study, we proposed a new plaque rupture mechanism, plaque separation at the shoulder, and developed a novel quantitative mechanical test to measure the adhesive strength between the atherosclerotic plaque and the underlying vascular wall in mouse models using the local energy release rate, G, as a quantifiable metric for direct comparison of plaque separation strengths (1). We have now investigated structure-function relationships between the local energy release rate and local plaque composition. We hypothesize that adhesive strength varies with plaque composition in mice of different genotypes, and that it correlates with collagen deposition and macrophage content in lesions. Mice which are genetically deficient in matrix metalloproteinase 12 (MMP12), have previously been shown to demonstrate altered lesion composition (2). Therefore, we used apoE knockout (KO) and apoE MMP-12 double knockout (DKO) mice for our experiments and expected to see a difference in local energy release rates between strains.

ON THE INVISCID LIMIT OF A MODEL FOR CRACK PROPAGATION

2008 ◽  
Vol 18 (09) ◽  
pp. 1529-1569 ◽  
Author(s):  
DOROTHEE KNEES ◽  
ALEXANDER MIELKE ◽  
CHIARA ZANINI
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Global Solutions ◽  
Inviscid Limit ◽  
Local Energy ◽  
Local And Global Solutions ◽  
Independent Process ◽  
Energy Release Rate Criterion ◽  
Rate Criterion

We study the evolution of a single crack in an elastic body and assume that the crack path is known in advance. The motion of the crack tip is modeled as a rate-independent process on the basis of Griffith's local energy release rate criterion. According to this criterion, the system may stay in a local minimum before it performs a jump. The goal of this paper is to prove the existence of such an evolution and to shed light on the discrepancy between the local energy release rate criterion and models which are based on a global stability criterion (as for example the Francfort/Marigo model). We construct solutions to the local model via the vanishing viscosity method and compare different notions of weak, local and global solutions.

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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