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  • 1
    Electronic Resource
    Electronic Resource
    Nonlinear swelling of polymer gels (1993)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 98 (1993), S. 4275-4293 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present a continuum theory for the nonlinear swelling of polymer gels. The approach is to solve the continuity equations for the network and liquid under the constraint that the instantaneous free energy be minimal. Constitutive relations are needed for the free energy density of the gel, W, and for the liquid diffusion current, J. The James–Guth phantom network model and Bastide's scaling model are used for W; Fick's law is used for J which is tantamount to neglecting the gel's shear modulus relative relative to its osmotic compressive modulus. The theory is applied to the free swelling of networks in good solvents to a semidilute gel for three geometries: sphere, long cylinder, and thin slab. We find a geometry-dependent, nonlocal effect influencing the measurables (gel shape and liquid uptake). This arises from the dependence of the network's deformation at the gel/liquid interface on the whole deformation field for the sample. The theory gives reasonable agreement with experiment; discrepancies are likely due to nonlocal effects in J not accounted for by Fick's law.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.465034
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  • 2
    Electronic Resource
    Electronic Resource
    An adaptation of finite linear viscoelasticity theory for rubber-like viscoelasticity by use of a generalized strain measure (1988)
    Springer
    Rheologica acta 27 (1988), S. 3-14 
    Details
    ISSN: 1435-1528
    Keywords: Generalizedstrain measure ; rubber-likeviscoelasticity ; constitutive theory ; finite linearviscoelasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract In this paper a simplified three-dimensional constitutive equation for viscoelastic rubber-like solids is derived by employing a generalized strain measure and an asymptotic expansion similar to that used by Coleman and Noll (1961) in their derivation of finite linear viscoelasticity (FLV) theory. The first term of the expansion represents exactly the time and strain separability relaxation behavior exhibited by certain soft polymers in the rubbery state and in the transition zone between the glassy and rubbery states. The relaxation spectra of such polymers are said to be deformation independent. Retention of higher order terms of the asymptotic expansion is recommended for treating deformation dependent spectra. Certain assumptions for the solid theory are relaxed in order to obtain a constitutive equation for uncross-linked liquid materials which exhibit large elastic recovery properties. Apart from the ‘strain energy’W(I1,I 2), which alternatively characterizes the long-time elastic response of solids or the instantaneous elastic response of elastic liquids, only the linear viscoelastic relaxation modulus is required for the first-order theory. Both types of material functions can be obtained, in theory, from simple laboratory testing procedures. The constitutive equations for solids proposed by Chang, Bloch and Tschoegl (1976) and a special form of K-BKZ theory for elastic liquids are shown to be particular cases of the first-order theory. Previously published experimental data on a cross-linked styrene-butadiene rubber (SBR) and an uncross-linked polyisobutylene (PIB) rubber is used to corroborate the theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01372444
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  • 3
    Electronic Resource
    Electronic Resource
    Critical tearing energy in a circumferentially-cracked circular cylinder of rubber under finite deformation (1992)
    Springer
    International journal of fracture 53 (1992), S. 129-157 
    Details
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper the circumferentially-cracked cylindrical (CCC) specimen is subjected to both asymptotic and finite element analyses to determine its suitability for measuring the critical tearing energy, T c of rubber-like materials. When deformed axially, these specimens produce uniform radial crack deformation and extension along the circular crack front. The local/pointwise value of tearing energy along the crack front is also uniform and therefore identical to the tearing energy magnitude obtained by global measurement techniques such as the compliance method. Application of the CCC specimen is illustrated on a non-crystallizing rubber (SBR). Experimental results and non-linear finite element analysis are used to show that the CCC specimen yields a constant value of T c which is statistically independent of crack depth and the two sizes of the specimen used in the experiments. The CCC specimen represents an improvement over pre-cracked thin sheet specimens used for measuring T c where it has been demonstrated (see Mazich, et al. [2]), that crack extension along the crack front is pointwise non-uniform resulting in a globally measured value for critical tearing energy that is very dependent on specimen thickness and therefore different from the purportedly invariant material parameter T c. The asymptotic analysis yields an expression relating tearing energy, T, deformed crack-tip radius, ρ0, and material shear modulus, G of the form: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0Jf9crFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamivaiabg2% da9maalaaabaGaaG4maaqaaiaaiIdaaaGaeqiWdaNaam4raiabeg8a% YnaaBaaaleaacaaIWaaabeaaaaa!409C!\[T = \frac{3}{8}\pi G\rho _0 \]. This expression yields numerical results which are in excellent agreement with the finite element predictions and test data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00034669
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  • 4
    Electronic Resource
    Electronic Resource
    Finite element analysis of sinusoidal small-amplitude vibrations in deformed viscoelastic solids. Part I: Theoretical development (1983)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 19 (1983), S. 1079-1103 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A general method is presented for the isothermal mechanical analysis of incompressible material solids in which a small-amplitude time harmonic oscillation is superposed on a static finite deformation field. Material behaviour is assumed to be of the ‘fading memory’ type describable by the finite linear viscoelasticity theory of Coleman and Noll.4 Existing finite element codes, that treat finite elasticity material behaviour, can be extended with minor modifications to treat the subject problem. A specialized form of the finite linear viscoelasticity constitutive equations proposed by Morman8 has been implemented in the MARC nonlinear finite element program for predicting the response of statically deformed elastomeric components to small amplitude vibrations. Numerical results obtained with MARC for the static force-deflection behaviour and dynamic (complex) stiffness for a viscoelastic cylinder subject to combined axial and twisting pre-loads, are in excellent agreement with corresponding analytical results.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620190712
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  • 5
    Electronic Resource
    Electronic Resource
    Determination of the complex shear modulus of structural adhesives using a doubly clamped sandwich beam (1992)
    Springer
    Experimental mechanics 32 (1992), S. 124-131 
    Details
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A method is described for calculating the complex shear modulus of structural adhesives from dynamic test data on a doubly clamped sandwich beam in which the adhesive is contained as a thin layer. The accuracy of the technique is validated by finite-element analysis. Values of modulus obtained using the doubly clamped beam technique are found to be in excellent agreement with values obtained from dynamic tests on bulk specimens of an epoxy adhesive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02324723
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  • 6
    Electronic Resource
    Electronic Resource
    Dynamic mechanical response of adhesively bonded beams: Effect of environmental exposure and interfacial zone properties (1990)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 249-255 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dynamic mechanical response of adhesively bonded metal beams has been examined over a broad temperature range using a dynamic mechanical thermal analyzer (DMTA). The measured dynamic mechanical response of the bonded beam contains rich information about the viscoelastic properties of the adhesive resin such as glass transition temperatures. The measured storage moduli and loss factors of the bonded beams are very sensitive to changes in the properties of adhesive induced by exposing the beam specimens to environmental attack. Dynamic mechanical responses associated with dry adhesive resin, water plasticized resin, and aggregated water were observed for an electro-galvanized steel/epoxy beam exposed to water. The effect of the presence of an interfacial accommodation zone (IAZ) between adhesive resin and metal substrate was also examined; measured properties were very sensitive to the presence of a low modulus IAZ. It was successfully demonstrated in this study that the DMTA testing of bonded beams is a potentially useful tool for studying dynamic performance and durability of automotive adhesive joints.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760300409
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