However, according to experience in diecasting and extrusion, uniaxial tensile elongation is not a particularly good indicator of deformation performance at high plastic strain
. The true fracture strain is a more useful parameter to characterize the response to plastic deformation.
where [DELTA][[epsilon].sup.pl] is the increment in plastic strain
and [[epsilon].sup.pl.sub.f] is the fracture plastic strain
where e and [eta] are the internal energy and the entropy per unit mass; p = tr([sigma])/3 and s are hydrostatic and deviatoric components of the Cauchy stress [sigma]; [delta]=tr([epsilon]) is the volumetric strain, [[bar.[epsilon]].sub.e] is the deviatoric elastic strain and [[epsilon].sub.p] is the plastic strain
; q is the heat flux vector per unit area and h is the heat source per unit mass; [rho] is the density and [theta] is the temperature.
where here [[bar.[epsilon]].sub.f] is effective plastic strain
to fracture, [eta] is stress triaxiality defined by the ratio of hydrostatic stress [[sigma].sub..sup.h] to equivalent stress [[sigma].sub.e].
 reported that the increasing residual plastic strain
decreased the permeability of carbon steels.
where [B.sup.*.sub.0] is a hardening parameter before the stress ratio reaches the phase transformation stress ratio [M.sup.*.sub.m], [[gamma].sup.p*.sub.r] is the reference plastic strain
, and [[gamma].sup.p*.sub.r] is accumulative plastic shear strain after phase transformation.
According to this model, the onset of shear damage is characterized by the value equivalent to plastic strain
at the initiation of shear damage [[epsilon].sup.pl.sub.S]].
[[epsilon].sup.p.sub.v] is the volumetric plastic strain
In addition, the equivalent viscous damping ratio, which reflects the plastic strain
energy, was relatively small for a column with a relatively big shear span ratio, which was due to the fact that the plastic strain
energy was mainly contributed by concrete cracking, which would be relatively less to a column with a relatively big shear span ratio, especially when the drift ratio was relatively small.
The maximum strain was the total of elastic and plastic strain
of the plates material.
In (1), A is the elastic limit; B and n are the characteristic constants of the hardening behavior; C denotes the sensitivity to the strain rate; [[??].sub.0] is the reference strain rate (typically set to 1/s); [[epsilon].sub.p] and [[??].sub.p] represent the plastic strain
and plastic strain
rate, respectively; T, [T.sub.a], [T.sub.f] are, respectively, the actual temperature, room temperature (293 K), and the melting absolute temperature; m is a material constant for the temperature tendency.