compression modulus

With the combination of the equilibrium compression modulus is as follows: E = y[GAMMA].

Here, [phi] denotes the porosity, [[phi].sub.0] is the initial porosity, [[epsilon].sub.v] the volumetric strain of the coal and rock masses, p (in Pa) is the pressure of the fluid, [p.sub.0] (in Pa) is initial pressure of the fluid, and [K.sub.S] represents the volumetric compression modulus of the coal and rock masses.

In Gurtler's research [7], the "in-plane" compression and shear experiments on FRP decks were conducted (Figure 3) to get the nominal compression modulus and nominal shear modulus of the whole FRP deck panel, which were used to develop the design methods for the FRP-steel composite girder system.

where [[nabla].sup.s]u = 1/2 ([nabla]u + [nabla][u.sup.1]) is the strain tensor with [nabla][u.sup.t] denoting the transpose of the matrix [nabla]u; [rho] is the density of the medium; the complex quantity [mu] + i[omega][eta] is the shear modulus, with [mu] indicating the storage modulus and [eta] indicating the loss modulus reflecting the attenuation of a viscoelastic medium; [lambda] and [[eta].sub.[lambda]] are the compression modulus and compression viscosity, respectively.

Simulated and experimental results were found to be very close to each other in respect of compression modulus of PLA material as illustrated in Fig: 9.

Compressive strain was higher than the tensile strain and further showed the difference between tension and compression elastic modulus, as the tension modulus of PSB was more than the compression modulus. The change of the ultimate strain range was wide, also showing the large variability in performances of PSB.

The small strain compression modulus is the same as the small strain tensile modulus only for very small strains.