Читать книгу The Rheology Handbook - Thomas Mezger - Страница 256

Sometimes, the J(t)-function in the rest phase is referred to as the (creep shear) recovery compliance Jr. Definition:

Equation 6.9

Jr(t) = γr(t) / τ0

unit: [1/Pa = Pa-1], with the re-formation γr [%]. The following holds for the equilibrium (shear) compliance Je:

Equation 6.10

Je = limt → ∞ Jr(t) (= J∞)

Je [1/Pa = Pa-1] is the limiting value of the Jr(t)-function after an “infinitely long” period of time, i. e. when t = ∞. The following holds: Je = J0

In the equilibrium state, the recovery compliance shows the same value if determined on the one hand via J(t) in an “infinitely short” period of time as above (in terms of J0), or, on the other hand via Jr(t) after an “infinitely long” period (in terms of Je or J∞), i. e. at the very end of the test when finally reaching again steady-state behavior or equilibrium of forces, respectively. However, when using the function of J(t) or Jr(t), the same value for J0 and Je may only be achieved if indeed the limiting value of the LVE deformation range has never been exceeded.