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Deformation tensile

There is another aspect of tensile deformation to be considered. The application of a distorting force not only stretches a sample, but it also causes the sample to contract at right angles to the stretch. If w and h represent the width and height of area A in Fig. 3.1, both contract by the same fraction, a fraction which is related in the following way to the strain ... [Pg.135]

Until now we have restricted ourselves to consideration of simple tensile deformation of the elastomer sample. This deformation is easy to visualize and leads to a manageable mathematical description. This is by no means the only deformation of interest, however. We shall consider only one additional mode of deformation, namely, shear deformation. Figure 3.6 represents an elastomer sample subject to shearing forces. Deformation in the shear mode is the basis... [Pg.155]

By analogy with Eq. (3.1), we seek a description for the relationship between stress and strain. The former is the shearing force per unit area, which we symbolize as as in Chap. 2. For shear strain we use the symbol y it is the rate of change of 7 that is involved in the definition of viscosity in Eq. (2.2). As in the analysis of tensile deformation, we write the strain AL/L, but this time AL is in the direction of the force, while L is at right angles to it. These quantities are shown in Fig. 3.6. It is convenient to describe the sample deformation in terms of the angle 6, also shown in Fig. 3.6. For distortion which is independent of time we continue to consider only the equilibrium behavior-stress and strain are proportional with proportionality constant G ... [Pg.156]

This result is the shear equivalent to Eq. (3.42) for tensile deformation. Note the modulus is a constant independent of strain for shear, while this is only true for a = 1 in the case of tension as shown by Eq. (3.43). [Pg.156]

The exponential term appears for the same reason as it does in diffusion it describes the rate at which molecules can slide past each other, permitting flow. The molecules have a lumpy shape (see Fig. 5.9) and the lumps key the molecules together. The activation energy, Q, is the energy it takes to push one lump of a molecule past that of a neighbouring molecule. If we compare the last equation with that defining the viscosity (for the tensile deformation of a viscous material)... [Pg.193]

The factor 3 appears because the viscosity is defined for shear deformation - as is the shear modulus G. For tensile deformation we want the viscous equivalent of Young s modulus . The answer is 3ri, for much the same reason that = (8/3)G 3G - see Chapter 3.) Data giving C and Q for polymers are available from suppliers. Then... [Pg.193]

Zug-verformung, /. tensile deformation, -ver-such, m. tensile test, tension test, -wagen, m. tractor, -wirkung,/. pulling effect, pull, zuheilen, v.i. heal up,... [Pg.535]

Fig. 5 Schematic representation of the domain contributions to the tensile deformation of the fibre chain stretching and chain rotation due to shear deformation... Fig. 5 Schematic representation of the domain contributions to the tensile deformation of the fibre chain stretching and chain rotation due to shear deformation...
In view of the development of the continuous chain model for the tensile deformation of polymer fibres, we consider the assumptions on which the Coleman model is based as too simple. For example, we have shown that the resolved shear stress governs the tensile deformation of the fibre, and that the initial orientation distribution of the chains is the most important structural characteristic determining the tensile extension below the glass transition temperature. These elements have to be incorporated in a new model. [Pg.81]

In order to simplify the discussion and keep the derivation of the formulae tractable, a fibre with a single orientation angle is considered. In a creep experiment the tensile deformation of the fibre is composed of an immediate elastic and a time-dependent elastic extension of the chain by the normal stress ocos20(f), represented by the first term in the equation, and of an immediate elastic, viscoelastic and plastic shear deformation of the domain by the shear stress, r =osin0(f)cos0(f), represented by the second term in Eq. 106. [Pg.83]

The tensile curve of a polymer fibre is characterised by the yield strain and by the strain at fracture. Both correspond with particular values of the domain shear strain, viz. the shear yield strain j =fl2 with 0.04rotation angle of -0y=fl2 and the critical shear strain 0-0b=/iwith /f=0.1. For a more fundamental understanding of the tensile deformation of polymer fibres it will be highly interesting to learn more about the molecular phenomena associated with these shear strain values. [Pg.111]

Baltussen JJM (1996) Tensile deformation of polymer fibres. PhD thesis, Delft University of Technology... [Pg.114]

Grubb, D. T., andjelinski, L. W. (1997). Fibre morphology of spider silk The effects of tensile deformation. Macromolecules 30, 2860-2867. [Pg.46]

Fig. 8.4 Plots of relative change in electrical resistance against tensile deformation of a CNT/epoxy composite (a) shows the various characteristics of the piezoresistivity of nanocarbon networks linear resistance change in the elastic regime, nonlinear region after inelastic deformation and the permanent electrical resistance drop due to plastic deformation (image adapted from [30]) ... Fig. 8.4 Plots of relative change in electrical resistance against tensile deformation of a CNT/epoxy composite (a) shows the various characteristics of the piezoresistivity of nanocarbon networks linear resistance change in the elastic regime, nonlinear region after inelastic deformation and the permanent electrical resistance drop due to plastic deformation (image adapted from [30]) ...
Integral over the total change in length of a sample of the incremental strain in uniaxial tensile deformation... [Pg.152]

Note 3 Young s modulus may he evaluated using tensile or compressive uniaxial deformation. If determined using tensile deformation it may be termed tensUe modulus. Note 4 For non-Hookean materials the Young s modulus is sometimes evaluated as ... [Pg.160]

TENSILE DEFORMATION BEHAVIOUR OF THE POLYMER PHASE OF FLEXIBLE POLYURETHANE FOAMS AND POLYURETHANE ELASTOMERS... [Pg.60]

Through the use of multiple experimental techniques, we have shown how both the NXL and XL phases of PILE interact and respond to applied tensile deformation. Strains transmitted to PILE crystals lead to two distinct slip modes and, at higher strains, to the breakup and alignment of lamellar fragments. In our experiments, crystallites in PTFE orient fuUy with respect to the draw direction at strains between 70 to 200%. With increasing strain, some chains originally in the XL phase are transformed to NXL material. Noncrystalline chains continue to orient until macroscopic failure is reached. This could be a fairly general microstructural response for semicrystalline polymers. [Pg.22]

Finally, tensile deformations provide the same information as shear deformation as long as the incompressibility assumption is not violated. In this case, the tensile stress relaxation modulus E(t) is directly related to the shear modulus E(t) = 3G(f), and all other relationships follow accordingly. [Pg.26]

Most testing of the theory has been done with tensile deformations. According to Eqs. (7.1) and (7.2) the nominal tensile stress /, the tensile force per unit unstretched area, is related to a, the ratio of stretched to unstretched length, by ... [Pg.102]

Equation (7.31) is a familiar form in statistical mechanics. For small displacements it is negative in sign and proportional to the square of displacement. For tensile deformation a power series expansion in the elongation ratio a, and with... [Pg.120]


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Cavitation tensile deformation

Constant deformation tests tensile specimen

Deformation Behaviour in Tensile and Burst Testing

Deformation under tensile load

Elastic and Tensile Deformations

Molding materials tensile deformation

Peel test tensile deformation

Plastic deformation under tensile load

Shear-deformation bands, fractured tensile

Subject tensile deformation

Tensile Stress Relaxation following Deformation at Constant Strain Rate

Tensile deformation catastrophic fracture

Tensile deformation critical strains

Tensile deformation finite plasticity

Tensile deformation localized stress-whitening

Tensile deformation strain control

Tensile deformation, HIPS

Tensile deformations, repeated

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