降伏厚面開關機制之理論實驗與應用(2/2)
Date Issued
2005
Date
2005
Author(s)
DOI
932211E002016
Abstract
The project was proposed to study mechenisms of switching, with the aim of applying to
switching between plastic and elastic phases in the problem of elastoplastic constitutive modeling
and switching between sliding and sticking in the problem of vibration control by friction. The focus
is on the switching mechanism associated with a yield thick-surface, but other feasible approaches
such as multiple complementary trios and transcritical bifurcation are also explored. In particular,
a variety of aspects of so-called complementary trios and variants are investigated.
In order to deal with the problems that the models with a conventional yield surface tend to
predict a loop of stress-strain curve which is over square in reverse loading and whose back stress
is over oscillatory in cyclic loading, we generalize a complementary trio to multiple complementary
trios, furthermore to a continuum of complementary trios. When associated with a yield surface a
complementary trio acts as a switching mechanism of single yield surface. By analogous association,
the multiple complementary trios thus act as a multiple yield surface switching mechanism, and
the complementary trio continuum a distributed yield surface switching mechanism. Alternatively,
we may thicken the yield surface so that the plastic-phase constitutive equations can develop their
capabilities in more ample space in stress space. To remedy the loss of consistency condition due
to the thickening, the yield thick-surface must be associated with a switching mechanism different
from that associated with the conventional zero-thickness yield surface.
Referring to the state and output equations in control dynamical system theory, we obtain a
general system of equations for elastoplatic evolution and state, which embrace most ingredients
of elastoplasticity such as elastic relations, elastic-plastic decomposition, plastic flow, hardeningsoftening,
etc. The significance of doing so is that the constitutive theory of elastoplasticity thus
has a clear relation with the theories of control dynamic systems and nonlinear ordinary differential
equations. On the basis of the latter we can deepen our research on plasticity.
Subjects
switching mechanism
two alternative phases
complementary trio
yield thick-surface
transcritical bifurcation
elastoplasticity
friction
Publisher
臺北市：國立臺灣大學土木工程學系暨研究所
Type
report
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