Tearing Energy as Fracture Mechanical Quantity for Elastomers

2016 ◽  
pp. 361-398 ◽  
Author(s):  
Radek Stoček ◽  
Thomas Horst ◽  
Katrin Reincke
Keyword(s):  
Mechanical Quantity ◽  
Tearing Energy

Effect of Filler Dispersion on Tensile Strength and Tearing Energy of Natural Rubber (NR) Latex Films

2015 ◽  
Vol 1134 ◽  
pp. 56-60 ◽  
Author(s):  
Siti Aisyah Jarkasi ◽  
Dzaraini Kamarun ◽  
Azemi Samsuri ◽  
Amir Hashim Md Yatim
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Latex Film ◽  
High Tensile Strength ◽  
Latex Films ◽  
Optimum Amount ◽  
Dispersing Agent ◽  
Two Factors ◽  
Filler Dispersion ◽  
Tearing Energy

Fillers play important roles in enhancing mechanical properties of NR latex films. The effect of filler dispersion and amount of dispersing agent to the tensile strength and tearing energy of NR latex films were investigated in this study. The studies were carried out by (i) varying the amount of dispersing agent (Anchoid) added which is an anionic surfactant; and (ii) varying the speed of stirring during mixing of latex with compounding ingredients. It was observed that tensile strength and tearing energy were affected by both factors listed. In the case of NR latex film filled with 10 pphr of carbon black (Super Abrasion Furnace, SAF), the optimum stirring speed was 400 rpm and the optimum amount of surfactant was in the range of 5 to 10 % by weight. High tensile strength ranging from 29 - 31 MPa and high tearing energies ranging from 90.6 - 111.0 kJ/m2were achieved from optimization of these two factors; rendering their importance.

Energy for crack growth in model rubber components

1972 ◽  
Vol 7 (2) ◽  
pp. 132-140 ◽  
Author(s):  
P B Lindley
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Crack Surface ◽  
Uniform Stress ◽  
Numerical Techniques ◽  
Surface Displacements ◽  
Tearing Energy ◽  
Crack Growth Rates ◽  
Essential Prerequisite

The determination of tearing energy, i.e. the energy available for crack growth, is an essential prerequisite for the estimation of the fatigue life of rubber components. Three methods of determining tearing energy are considered: from changes in total energy, from crack surface displacements, and by comparison with known values for the same crack growth rates. It is shown by applying experimental and numerical techniques to plane-stress testpieces, not necessarily of uniform stress or thickness, that the methods are satisfactory.

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 % .

Contributions of Time Dependent and Cyclic Crack Growth to the Crack Growth Behavior of Non Strain-Crystallizing Elastomers

2002 ◽  
Vol 75 (4) ◽  
pp. 643-656 ◽  
Author(s):  
J. J. C. Busfield ◽  
K. Tsunoda ◽  
C. K. L. Davies ◽  
A. G. Thomas
Keyword(s):  
Crack Growth ◽  
Growth Behavior ◽  
Time Dependent ◽  
Crack Growth Behavior ◽  
Wide Range ◽  
Dependent Component ◽  
Tearing Energy ◽  
Quasi Crystals ◽  
Crack Growth Rates ◽  
Time Dependent Crack Growth

Abstract Engineering components are observed to fail more rapidly under cyclic loading than under static loading. This reflects features of the underlying crack growth behavior. This behavior is characterized by the relation between the tearing energy, T, and the crack growth per cycle, dc/dn. The increment of crack growth during each cycle is shown here to result from the sum of time dependent and cyclic crack growth components. The time dependent component represents the crack growth behavior that would be present in a conventional constant T crack growth test. Under repeated stressing additional crack growth, termed the cyclic crack growth component, occurs. For a non-crystallizing elastomer, significant effects of frequency have been found on the cyclic crack growth behavior, reflecting the presence of this cyclic element of crack growth. The cyclic crack growth behavior over a wide range of frequencies was investigated for unfilled and swollen SBR materials. The time dependent crack growth component was calculated from constant T crack growth tests and the cyclic contribution derived from comparison with the observed cyclic growth. It is shown that decreasing the frequency or increasing the maximum tearing energy during a cycle results in the cyclic crack growth behavior being dominated by time dependent crack growth. Conversely at high frequency and at low tearing energy, cyclic crack growth is dominated by the cyclic crack growth component. A large effect of frequency on cyclic crack growth behavior was observed for highly swollen SBR. The cyclic crack growth behavior was dominated by the time dependent crack growth component over the entire range of tearing energy and/or crack growth rate. The origin of the cyclic component may be the formation/melting of quasi crystals at the crack tip, which is absent at fast crack growth rates in the unswollen SBR and is absent at all rates in the swollen SBR.

Assessing the Tearing Energy of a Hydrocarbon Elastomeric Seal Material for Fuel Cell Applications

Fuel Cells ◽  
2014 ◽  
Vol 14 (4) ◽  
pp. 543-550 ◽  
Author(s):  
Justin E. Klein ◽  
Hitendra K. Singh ◽  
Gilles M. Divoux ◽  
Scott W. Case ◽  
David A. Dillard ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Tearing Energy

Electrostatic Potential at Nuclei

2014 ◽  
pp. 87-122
Author(s):  
Sonia Ilieva ◽  
Boris Galabov
Keyword(s):  
Hydrogen Bonding ◽  
Kinetic Parameters ◽  
Organic Compounds ◽  
Electrostatic Potential ◽  
Original Work ◽  
Computational Approach ◽  
Reactivity Index ◽  
Quantum Mechanical ◽  
Mechanical Quantity ◽  
Substituent Constants

The chapter surveys mostly original work of the authors on the application of the electrostatic potential at nuclei (EPN) as a reactivity index in quantifying hydrogen bonding as well as different reactions of organic compounds. The EPN index was defined and introduced by E. B. Wilson (1962). However, it was first applied as a reactivity index much later in works from our laboratory (Bobadova-Parvanova & Galabov, 1998; Galabov & Bobadova-Parvanova, 1999; Dimitrova, Ilieva, & Galabov, 2002; Cheshmedzhieva, Ilieva, Hadjieva, Trayanova, & Galabov, 2009; Galabov, Cheshmedzhieva, Ilieva, & Hadjieva, 2004; Galabov, Ileiva, & Schaefer, 2006; Galabov, Nikolova, Wilke, Schaefer, & Allen, 2008; Galabov, Ilieva, Hadjieva, Atanasov, & Schaefer, 2008; Koleva, Galabov, Wu, Schaefer, & Schleyer, 2009). Numerous applications showed that the EPN index, an accurate quantum mechanical quantity, predicts with remarkable accuracy the energy shifts accompanying hydrogen bonding. The theoretically evaluated EPN descriptor correlates also excellently with experimental and theoretically evaluated kinetic parameters for a number of important organic reactions. Based on these findings an efficient computational approach for the evaluation of substituent constants was developed.

Electrostatic Potential at Nuclei

2011 ◽  
pp. 280-317
Author(s):  
Sonia Ilieva ◽  
Boris Galabov
Keyword(s):  
Hydrogen Bonding ◽  
Kinetic Parameters ◽  
Electrostatic Potential ◽  
Computational Approach ◽  
Organic Reactions ◽  
Quantum Mechanical ◽  
Mechanical Quantity ◽  
Substituent Constants

Numerous applications showed that the EPN index, an accurate quantum mechanical quantity, predicts with remarkable accuracy the energy shifts accompanying hydrogen bonding. The theoretically evaluated EPN descriptor correlates also excellently with experimental and theoretically evaluated kinetic parameters for a number of important organic reactions. Based on these findings an efficient computational approach for the evaluation of substituent constants was developed.

The Effect of Specimen Thickness on the Tearing Energy of a Gum Vulcanizate

1989 ◽  
Vol 62 (5) ◽  
pp. 850-862 ◽  
Author(s):  
Kenneth A. Mazich ◽  
K. N. Morman ◽  
F. G. Oblinger ◽  
T. Y. Fan ◽  
P. C. Killgoar
Keyword(s):  
Finite Element ◽  
Laboratory Experiments ◽  
Pure Shear ◽  
Thickness Effect ◽  
Specimen Thickness ◽  
J Integral ◽  
Shear Specimen ◽  
Standard Specimens ◽  
Finite Element Calculations ◽  
Tearing Energy

Abstract We have examined the effect of thickness on the critical tearing energy of a simple gum vulcanizate of SBR in pure shear. Laboratory experiments and finite-element calculations agree that the tearing energy that is measured with a pure-shear specimen increases with the thickness of the specimen. Laboratory measurements indicate that the deformation for crack growth in a pure-shear specimen increases with the thickness of the specimen. Finite-element calculations show that the energy available for release at a given deformation also increases with thickness in the range from t=1.4 mm to t=14 mm. Experiments show that the crtical tearing energy varies linearly with thickness in the range t=0.7 mm to t=2.7 mm. The effect of thickness on the tearing energy was also studied by calculating the J-integral at various points of the crack through the thickness of the pure-shear specimen. In general, the J-integral calculated at the surface of the specimen can be higher than the J-integral calculated at the center of the specimen for specimens that are sufficiently thick. The thickness effect measured in this work suggests that the “critical tearing energy” obtained from standard laboratory specimens may not be a true material property. For this reason, critical tearing energy that is measured on standard specimens may not be generally applied to predict failure in arbitrary elastomeric components.

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