...
Time-history
...
analysis
...
provides
...
for
...
linear
...
or
...
...
evaluation
...
of
...
dynamic
...
structural
...
response
...
under
...
loading
...
which
...
may
...
vary
...
according
...
to
...
the
...
specified
...
...
...
.
...
Dynamic
...
equilibrium
...
equations,
...
given
...
by
...
K
...
u(t)
...
+
...
C
...
d/
...
dt u(t)
...
+
...
M
...
d
...
2/dt u(t)
...
=
...
r(t),
...
are
...
solved
...
using
...
either
...
...
or
...
...
...
methods.
...
Initial
...
conditions
...
may
...
be
...
set
...
by
...
continuing
...
the
...
structural
...
state
...
from
...
the
...
end
...
of
...
the
...
previous
...
analysis.
...
Additional
...
notes
...
include:
...
- Step
...
- Size
...
- – Direct-integration
...
- methods
...
- are
...
- sensitive
...
- to
...
- time-step
...
- size,
...
- which
...
- should
...
- be
...
- decreased
...
- until
...
- results
...
- are
...
- not
...
- affected.
...
- HHT
...
- Value
...
- – A
...
- slightly
...
- negative
...
...
- alpha
...
- value
...
- is
...
- also
...
- advised
...
- to
...
...
- out
...
- higher
...
- frequency
...
- modes,
...
- and
...
- to
...
- encourage
...
- convergence
...
- of
...
- nonlinear
...
- direct-integration
...
- solutions.
...
- Nonlinearity – Material and geometric nonlinearity, including P-delta and large-displacement effects, may be simulated during nonlinear direct-integration time-history analysis.
See Also
- Multi-support excitation article