On the Puncture Mechanics of Rubber

1994 ◽  
Vol 67 (5) ◽  
pp. 743-760 ◽  
Author(s):  
A. Stevenson ◽  
Kamarudin Ab Malek
Keyword(s):  
Fracture Mechanics ◽  
Elasticity Theory ◽  
Theoretical Approach ◽  
Elastic Energy ◽  
Model Experiment ◽  
Crack Formation ◽  
Biaxial Stretching ◽  
Rubber Surface ◽  
Tearing Energy ◽  
Ring Crack

Abstract The mechanics of puncture have been studied experimentally and theoretically, by means of fracture mechanics. When a sharp cylindrical indentor penetrates rubber, a starter crack initiates as a ring on the rubber surface before puncture occurs. By treating this as militating puncture, an equation has been derived for the energy of puncture. The elastic energy stored in the rubber is considered in terms of the energy beneath and surrounding the indentor. An equation for the energy beneath the indentor is determined with the aid of a model experiment based on the biaxial stretching of rubber by inflation. The energy stored in the rubber surrounding the indentor is calculated using elasticity theory. The magnitude of these contributions is assessed for different indentor sizes and different rubber vulcanizates, The theoretical approach is shown to be verified by a series of experiment for sharp indentors. The values of puncture energy so obtained were found to agree well with the catastrophic tearing energy obtained from trouser tear tests. For blunt indentors which do not cause ring crack formation, other considerations are needed. These are discussed together with experimental results for hemispherical indentors.

scholarly journals An experimental method for estimating the tearing energy in rubber-like materials using the true stored energy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elsiddig Elmukashfi
Keyword(s):  
Crack Propagation ◽  
Viscous Dissipation ◽  
Simple Shear ◽  
Elastic Energy ◽  
Classical Method ◽  
Pure Shear ◽  
Dissipated Energy ◽  
Dynamic Experiments ◽  
Unloading Rate ◽  
Tearing Energy

AbstractA method for determining the critical tearing energy in rubber-like materials is proposed. In this method, the energy required for crack propagation in a rubber-like material is determined by the change of recovered elastic energy which is obtained by deducting the dissipated energy due to different inelastic processes from the total strain energy applied to the system. Hence, the classical method proposed by Rivlin and Thomas using the pure shear tear test is modified using the actual stored elastic energy. The total dissipated energy is evaluated using cyclic pure shear and simple shear dynamic experiments at the critical stretch level. To accurately estimate the total dissipated energy, the unloading rate is determined from the time the crack takes to grow an increment. A carbon-black-filled natural rubber is examined in this study. In cyclic pure shear experiment, the specimens were cyclically loaded under quasi-static loading rate of $$0.01~{\rm {s}}^{-1}$$ 0.01 s - 1 and for different unloading rates, i.e. $$0.01$$ 0.01 , $$0.1$$ 0.1 and $$1.0~{\rm {s}}^{-1}$$ 1.0 s - 1 . The simple shear dynamic experiment is used to obtain the total dissipated energy at higher frequencies, i.e. $$0.5$$ 0.5 -$$18~{\rm {Hz}}$$ 18 Hz which corresponds to unloading rates $$0.46$$ 0.46 -$$16.41~{\rm {s}}^{-1}$$ 16.41 s - 1 , using the similarities between simple and pure shear deformation. The relationship between dissipated energy and unloading stretch rate is found to follow a power-law such that cyclic pure shear and simple shear dynamic experiments yield similar result. At lower unloading rates (i.e. $${\dot{\lambda }}_{\rm {U}} < 1.0~{\rm {s}}^{-1}$$ λ ˙ U < 1.0 s - 1 ), Mullins effect dominates and the viscous dissipation is minor, whereas at higher unloading rates, viscous dissipation becomes significant. At the crack propagation unloading rate $$125.2~{\rm {s}}^{-1}$$ 125.2 s - 1 , the viscous dissipation is significant such that the amount of dissipated energy increases approximately by $$125.4\%$$ 125.4 % from the lowest unloading rate. The critical tearing energy is obtained to be $$7.04~{\rm {kJ}}/{\rm {m}}^{2}$$ 7.04 kJ / m 2 using classical method and $$5.12~{\rm {kJ}}/{\rm {m}}^{2}$$ 5.12 kJ / m 2 using the proposed method. Hence, the classical method overestimates the critical tearing energy by approximately $$37.5\%$$ 37.5 % .

A further insight into spherical indentation: Ring crack formation in a brittle La0.8Sr0.2Ga0.8Mg0.2O3 perovskite

2011 ◽  
Vol 59 (11) ◽  
pp. 4425-4436 ◽  
Author(s):  
M. Lugovy ◽  
V. Slyunyayev ◽  
S. Yarmolenko ◽  
J. Sankar ◽  
T. Graule ◽  
...  
Keyword(s):  
Crack Formation ◽  
Spherical Indentation ◽  
Ring Crack ◽  
Insight Into

Plane Asymptotic Interface Crack Solutions in Gradient Elasticity Theory

2016 ◽  
Vol 713 ◽  
pp. 151-154
Author(s):  
Michal Kotoul ◽  
Tomáš Profant ◽  
Petr Padělek
Keyword(s):  
Fracture Mechanics ◽  
Elasticity Theory ◽  
Plane Strain ◽  
Interface Crack ◽  
Strain Gradient ◽  
Special Form ◽  
Gradient Elasticity ◽  
Strain Gradient Elasticity ◽  
The Past ◽  
Gradient Elasticity Theory

The goal of the contribution is to develop an asymptotic interface crack-tip solution under conditions of plane strain for a bi-material that obeys a special form of linear isotropic gradient elasticity. Several fracture mechanics problems have been solved in the past within the framework of strain gradient elasticity which is capable to capture additional length/size parameters. However to our best knowledge no solution concerning an interface crack is available in the literature.

General Elasticity Theory for Graphene Membranes Based on Molecular Dynamics

2007 ◽  
Vol 1057 ◽  
Author(s):  
Kaveh Samadikhah ◽  
Juan Atalaya ◽  
Caroline Huldt ◽  
Andreas Isacsson ◽  
Jari Kinaret
Keyword(s):  
Molecular Dynamics ◽  
Elasticity Theory ◽  
Elastic Energy ◽  
Poisson Ratio ◽  
Md Simulations ◽  
Energy Functional ◽  
Linear Description ◽  
Continuum Description ◽  
External Forces ◽  
Graphene Membranes

ABSTRACTWe have studied the mechanical properties of suspended graphene membranes using molecular dynamics (MD) and generalized continuum elasticity theory (GE) in order to develop and assess a continuum description for graphene. The MD simulations are based on a valence force field model which is used to determine the deformation and the elastic energy of the membrane (EMD) as a function of external forces. For the continuum description, we use the expression Econt = Estretching + Ebending for the elastic energy functional. The elastic parameters (tensile rigidity and Poisson ratio) entering Econt are determined by requiring that Econt = EMD for a set of deformations.Comparisons with the MD results show excellent agreement. We find that the elastic energy of a supported graphene sheets is typically dominated by the nonlinear stretching terms whereas a linear description is valid only for very small deflections. This implies that in some applications, i.e. NEMS, a linear description is of limited applicability.

scholarly journals Rate-dependence of ‘wet’ biological adhesives and the function of the pad secretion in insects

Soft Matter ◽  
2015 ◽  
Vol 11 (44) ◽  
pp. 8661-8673 ◽  
Author(s):  
David Labonte ◽  
Walter Federle
Keyword(s):  
Energy Dissipation ◽  
Fracture Mechanics ◽  
Theoretical Approach ◽  
Rate Dependence ◽  
Force Measurements ◽  
Biological Adhesives

We combine detailed force measurements on isolated attachment organs of live insects with a theoretical approach based on fracture mechanics to show that viscous energy dissipation of ‘wet’ insect pads is akin to that of ‘dry’ elastomers.

Delamination modelling of a curved composite beam subjected to an opening bending moment

2003 ◽  
Vol 38 (5) ◽  
pp. 453-457 ◽  
Author(s):  
W Wang ◽  
R. A Shenoi
Keyword(s):  
Fracture Mechanics ◽  
General Solution ◽  
Critical Load ◽  
Theoretical Approach ◽  
Composite Beam ◽  
Beam Theory ◽  
Bending Moment ◽  
Radius Of Curvature ◽  
Curved Beam ◽  
Mechanics Concepts

A theoretical approach is developed for the case of delamination of a curved composite beam under an opening bending moment. This is based on linear curved beam theory coupled with fracture mechanics concepts. The general solution is applied to analyse a specific case of delamination occurring at the mid-plane. The effects of the arc angle of delamination crack and the radius of curvature of the beam on the critical load are also studied.

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