Specimen size effect during tensile testing of an unreinforced polymer

Odom, Edwin; Adams, Donald F.

doi:10.1007/bf01107202

Cited by 48 publications

(22 citation statements)

References 5 publications

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“…Size effects have also been observed in unreinforced epoxy matrix materials. Odom and Adams [38] reported on tensile strength reduction with increasing volume of specimens. Tensile and flexural strength reductions with increasing volume were also reported by Seo and Lim [39].…”

Section: Size Effects On Strength In Frp Materialsmentioning

confidence: 97%

Probabilistic strength prediction for double lap joints composed of pultruded GFRP profiles – Part II: Strength prediction

Vallée

Correia

Keller

2006

Composites Science and Technology

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Section: Size Effects On Strength In Frp Materialsmentioning

confidence: 97%

Probabilistic strength prediction for double lap joints composed of pultruded GFRP profiles – Part II: Strength prediction

Vallée

Correia

Keller

2006

Composites Science and Technology

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“…While there are no standards for simulated molecular mechanical property characterization, standard macroscale mechanical tensile tests utilize dogbone-shaped specimens to ensure a concentration of loading on a narrow portion of the sample with a precisely known cross-sectional area. In general, these tests result in a scale-invariant elastic modulus until smaller dimensions are reached, where moduli tend to increase and become more variable (37,38). While single molecule experiments have been performed on single proteins as they unfold (e.g., (39)), the opportunity to interrogate a single tubulin monomer in its naturally occurring state has not been realized.…”

Section: Parameters Used Boundary Conditions and Optimizationmentioning

confidence: 99%

Molecular Modeling of the Axial and Circumferential Elastic Moduli of Tubulin

Zeiger

Layton

2008

Biophysical Journal

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Microtubules play a number of important mechanical roles in almost all cell types in nearly all major phylogenetic trees. We have used a molecular mechanics approach to perform tensile tests on individual tubulin monomers and determined values for the axial and circumferential moduli for all currently known complete sequences. The axial elastic moduli, in vacuo, were found to be 1.25 GPa and 1.34 GPa for alpha- and beta-bovine tubulin monomers. In the circumferential direction, these moduli were 378 MPa for alpha- and 460 MPa for beta-structures. Using bovine tubulin as a template, 269 homologous tubulin structures were also subjected to simulated tensile loads yielding an average axial elastic modulus of 1.10 +/- 0.14 GPa for alpha-tubulin structures and 1.39 +/- 0.68 GPa for beta-tubulin. Circumferentially the alpha- and beta-moduli were 936 +/- 216 MPa and 658 +/- 134 MPa, respectively. Our primary finding is that that the axial elastic modulus of tubulin diminishes as the length of the monomer increases. However, in the circumferential direction, no correlation exists. These predicted anisotropies and scale dependencies may assist in interpreting the macroscale behavior of microtubules during mitosis or cell growth. Additionally, an intergenomic approach to investigating the mechanical properties of proteins may provide a way to elucidate the evolutionary mechanical constraints imposed by nature upon individual subcellular components.

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“…da Silva et al [11] found that the fracture toughness of Araldite 2015 in Mode II increases with the adhesive thickness. Odom and Adams [12] tested dog-bone shaped specimens and observed a drastic increase in the strength of smaller specimens which they attributed to the reduction of flaw size. Hobbiebrunken et al [13] proposed a method to produce μm-sized epoxy fibers, the average strength of which was found to be remarkably close (60%) to the theoretical strength.…”

Section: Introductionmentioning

confidence: 99%

Extreme scale-dependent tensile properties of epoxy fibers

Sui¹,

Tiwari²,

Greenfeld³

et al. 2019

Express Polym. Lett.

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Epoxy fibers with different diameters were prepared by hot drawing and their mechanical properties were measured under tension. The stiffness, strength, ultimate strain, and toughness revealed substantial scale-dependent effects as they all significantly increased with a decrease in size. Compared to bulk epoxy, an intrinsically brittle material, thin epoxy fibers displayed a highly ductile behavior under tension. A drop in stress observed immediately beyond the yield point was followed by the development of a stable necking region propagating through the entire fiber length, then by strain-hardening up to final rupture. Necked fiber segments tested in tension were found to have even higher strength and modulus compared to the initial as-prepared fibers. Possible reasons for the highly ductile mechanical behavior and the size effects of epoxy fibers are discussed. Size effects for the strength of epoxy can be elucidated in principle either by means of a classical fracture mechanics argument (strength~1/d 1/2), or via a stochastic model argument (strength~1/d 1/β , where β is a function of the material and is generally larger than 2). In both models the presence and size of critical defects play a key role. However, defects cannot explain the colossal ductility (plastic deformation) seen in our experiments, nor can the presence of defects justify a size effect in an elastic property, namely Young's modulus. Only scarce evidence exists in the literature for similar (milder) size effects in epoxy fibers but without any structural justification. We find here that highly cross-linked necked epoxy fibers exhibit partial macromolecular anisotropy which likely explains the observed high mechanical characteristics.

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Specimen size effect during tensile testing of an unreinforced polymer

Cited by 48 publications

References 5 publications

Probabilistic strength prediction for double lap joints composed of pultruded GFRP profiles – Part II: Strength prediction

Probabilistic strength prediction for double lap joints composed of pultruded GFRP profiles – Part II: Strength prediction

Molecular Modeling of the Axial and Circumferential Elastic Moduli of Tubulin

Extreme scale-dependent tensile properties of epoxy fibers

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