But Young's modulus is a measure of stiffness calculated by measuring the change in the length of a sample when it is placed under a uniaxial stress
, either in tension or compression.
(2015) established a damage model considering the cyclic uniaxial stress
and cyclic temperature for basalt rocks.
In most papers, the mechanical behavior of polymers has been studied under uniaxial stress
states with a unique sign: tension or compression.
According to the equivalent strain hypothesis theory proposed by Lemaitre , the constitutive relation of damaged material can be derived from the constitutive equation of the nondestructive material under uniaxial stress
by replacing the nominal stress of the constitutive relation of the undamaged material with the effective stress.
Effect of uniaxial stress
on the dielectric properties of BaTi[O.sub.3] + 0.1wt.%[Eu.sub.2][O.sub.3] ceramics.
In this case, [[sigma].sub.11] = [[sigma].sub.u] = [M.sub.Z]/I, and [[sigma].sub.22] = [[sigma].sub.33] = 0, where M here is the bending moment applied to the beam, I is the beam moment of inertia, z is the distance from the neutral axis, and [[sigma].sub.u] is the resulting uniaxial stress
Analysis of the uniaxial stress
state is conducted under displacement control along axis 2 that corresponds to the axis of load application.
Tao  tested the failure strength of soft and hard coal specimens under the PSBSS and they found out that greater failure strengths will appear under the PSBSS than those under uniaxial stress
state for both kinds of coal specimens.
The experimental results of DF with large l are all obtained from the uniaxial stress
growth coefficient using a method proposed by Wagner et al .
Under uniaxial stress
state, [[lambda].sub.1] = [[lambda].sub.u], [[lambda].sub.2] = [[lambda].sub.3] = [[lambda].sub.u.sup.-1/2].