Quasi-Static and High Strain Rate Simple Shear Characterization of Soft Polymers

Upadhyay, Kshitiz; Bhattacharyya, Abir; Subhash, Ghatu; Spearot, Douglas E.

doi:10.1007/s11340-019-00507-1

Cited by 25 publications

(21 citation statements)

References 53 publications

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“…From Table 1, the direct shear characterisation using the proposed methodology yielded shear modulus values that are closer in magnitude to the shear modulus values in Subhash et al [7] (calculated from Equation 1 using uniaxial moduli) when compared to those obtained in Upadhyay et al [28] This is likely the result of the refined method of using 2-D DIC on both side faces of the specimen, compared to the single-sided DIC commonly employed in the literature. [6,32,[34][35][36] Single-sided DIC measures the local shear strains on a single face of the test specimen and pairs it to an average shear stress for the entire sample, thus not accounting for non-uniform strain distribution or twist within the specimen itself. On the other hand, using 2-D DIC and the integration method on both specimen faces accounts for these non-uniformities and twist resulting in a more accurate method of capturing the shear behaviour of the soft material.…”

Section: Resultsmentioning

confidence: 99%

“…Fine chalk powder (100–200 μm) was blown onto both sides of the test specimen to create a random, homogeneous pattern across the test area. [ 34 ] Images of the specimen's deformation were taken at regular intervals of one picture per second using two 5.0‐MP CCD cameras (GRAS‐50S5M‐C [Sony ICX 625 CCD], FLIR Systems, Inc., Richmond, Canada). The pixel resolution of the cameras is 2,448 × 2,048 pixels, and the spatial resolution is ~40 pixels mm −1 , such that around 140 pixels exist along the width of the specimen test section.…”

Section: Experimental Methodsmentioning

confidence: 99%

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An improved direct shear characterisation technique for soft gelatinous and elastomeric materials

Millar

Mennu

Upadhyay

et al. 2021

Strain

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Soft materials such as hydrogels and elastomers exhibit very low stiffness and strength as well as large deformations, which makes their mechanical characterisation extremely difficult through conventional methods. This paper presents a novel experimental technique for the mechanical shear property characterisation of these materials. Agarose hydrogels were chosen as a model material for this study. The new in‐plane shear test method incorporates 3‐D‐printed acrylonitrile butadiene styrene (ABS) grips for specimen mounting and digital image correlation (DIC) for full‐field strain measurement on both sides of the specimen gauge section. These grips utilise barb‐like pegs to secure the specimen while load is applied. In order to evaluate the methodology, four concentrations of agarose hydrogel (4.0%, 2.5%, 1.5%, and 0.5% wt./solvent volume) were tested. Results for the agarose hydrogel demonstrated excellent repeatability. The obtained shear moduli show a monotonic increase with gel concentration. Furthermore, the range of shear moduli applicable to the novel testing method was determined.

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Section: Resultsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

An improved direct shear characterisation technique for soft gelatinous and elastomeric materials

Millar

Mennu

Upadhyay

et al. 2021

Strain

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“…For material characterisation and model parameter identification, simple shear is a very important deformation state (cf. other works [ 1‐11 ] and Upadhyay et al [ 12 ] ). Especially for engineering components like rubber bushings or earthquake isolation bearings, simple shear plays a very important role.…”

Section: Introductionmentioning

confidence: 86%

“…As pointed out in literature, a basic problem of simple shear deformation is the uniform load introduction (cf. Whitney et al [ 1 ] and Upadhyay et al [ 12 ] ). One of the best‐known representatives of simple shear specimens is the cylindrical double‐shear‐specimen, used at the Tun Abdul Razak Research Centre (TARRC) in Hertford (cf.…”

Section: Introductionmentioning

confidence: 99%

Development of a shear device for precise simple shear measurements of rubber mats

Kanzenbach

Ihlemann

2021

Strain

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This contribution deals with the development of a new shear specimen, which allows precise simple shear measurements for large shear values. The main idea is that the shear load for the rubber mat is applied via steel pins. A form fit connection has the advantage that for the load application, no clamping force or high friction coefficient is required. In addition, the disadvantages resulting from vulcanisation or bonding, for example, shrinkage, are avoided. This offers the big advantage that homogeneous ageing tests can be performed, and also fibre‐reinforced materials can be tested. In order to show the potential of the new pin design, simulation results are compared to each other, and also a first experimental implementation is conducted. The new shear specimen can be used for phenomenological investigations of rubber properties, like Payne effect, Mullins effect, anisotropy, permanent set, softening, recovery, creep and relaxation behaviour.

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“…Ultrapure water is produced by a Milli-Q water purification system (Millipore Corporation, Bedford, MA). Hydrogel specimens are prepared by first dissolving PEGDA in ultrapure water to obtain A previous study by the authors 50 developed an approach to perform simple shear experiments on polydimethylsiloxane at high strain rates using a modified split-Hopkinson pressure bar (SHPB) setup. This experimental approach is adopted in this work to investigate the shear-thickening behavior in PEGDA hydrogels.…”

Section: Simulation and Experimental Methodsmentioning

confidence: 99%

Transient-State Rheological Behavior of Poly(ethylene glycol) Diacrylate Hydrogels at High Shear Strain Rates

et al. 2019

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Transient rheological properties of poly(ethylene glycol) diacrylate (PEGDA) hydrogels under Couette flow conditions are determined via molecular dynamics simulations and validated by high strain rate shear experiments. Specifically, the influence of polymer concentration on the transient-state shear-thickening behavior is studied for 20, 25, 50, and 70 wt % PEGDA hydrogels. The transient shear response is characterized by the introduction of dimensionless variables and the application of a self-similar solution to the power-law fluid model. This enables meaningful comparison of the shear-thickening exponent and the transient-state viscosity across the disparate length and time scales between simulations and experiments. The momentum diffusion exponent is found to increase with a decrease in PEGDA concentration, which indicates higher shear-thickening behavior in lower PEGDA concentration hydrogels. Shear-thickening mechanisms in hydrogels are explained by computing the average mesh sizes in the polymer networks and the distributions of junction separations. Two stages of PEGDA chain deformations are observed under shear, where the first stage is associated with chain conformational changes and the second stage is associated with bond length and angular deviations. Hydrogels with lower PEGDA concentration show a faster increase in the average mesh size, which offers higher resistance to shear in both deformation stages, promoting greater shear-thickening behavior.

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Quasi-Static and High Strain Rate Simple Shear Characterization of Soft Polymers

Cited by 25 publications

References 53 publications

An improved direct shear characterisation technique for soft gelatinous and elastomeric materials

An improved direct shear characterisation technique for soft gelatinous and elastomeric materials

Development of a shear device for precise simple shear measurements of rubber mats

Transient-State Rheological Behavior of Poly(ethylene glycol) Diacrylate Hydrogels at High Shear Strain Rates

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