Forced uniaxial extensional oscillation

Note 4 Unlike the strain in forced uniaxial extensional oscillations, those in forced flexural deformations are not homogeneous. In the latter modes of deformation, the strains vary from point-to-point in the specimen. Hence, the equation defining the displacement y in terms of the amplitude of applied force (/q) caimot be converted into one defining strain in terms of amplitude of stress. 

Note 4 Under a forced uniaxial extensional oscillation the resonance frequency... 

Note 1 For a material specimen which behaves as a Voigt-Kelvin solid under forced uniaxial extensional oscillation with mass added at the point of application of the applied oscillatory force, Av is proportional to the loss modulus (E"). 

Note 7 Notes 2 and 5 show that application of a sinusoidal uniaxial force to a Voigt-Kelvin solid of negligible mass, with or without added mass, results in an out-of-phase sinusoidal uniaxial extensional oscillation of the same frequency. 

There are three modes of free and forced oscillatory deformations which are commonly used experimentally, torsional oscillations, uniaxial extensional oscUlations and flexural oscillations. 

Note 2 For specimens without mass, the linear-viscoelastic interpretation of the resulting deformations follows a differential equation of the same form as that for a uniaxial extensional forced oscillation, namely... 

---