...
If
...
numerical
...
instability
...
occur
...
within
...
an
...
...
model,
...
we
...
recommend
...
considering
...
the
...
basic
...
troubleshooting
...
techniques
...
which
...
follow:
...
- Stability
...
- .
...
- Under
...
- the
...
- File
...
- menu,
...
- check
...
- the
...
- last
...
- analysis
...
- run
...
- log
...
- to
...
- ensure
...
- that
...
- the
...
- model
...
- is
...
- stable.
...
- Results
...
- from
...
- an
...
- unstable
...
- model
...
- are
...
- not
...
- reliable.
...
- Releases
...
- .
...
- Do
...
- not
...
- release
...
- moment
...
- for
...
- objects
...
- adjoined
...
- at
...
- the
...
- same
...
...
- ,
...
- such
...
- as
...
- with
...
- beam-column
...
- connections.
...
- Multiple
...
- coincident
...
- releases
...
- will
...
- cause
...
...
...
- .
...
- If
...
- necessary,
...
- one
...
- object
...
- may
...
- be
...
- released.
...
- Self
...
- weight
...
- .
...
- Ensure
...
- that
...
- deflected
...
- configuration
...
- under
...
- self-weight
...
- is
...
- as
...
- expected.
What does it mean when numerical instability warnings are reported, but there is no joint at the location indicated?
Answer: Numerical instability is reported according to numerical formulation and the sequence in which equations are solved. The point indicated is not necessarily a discrete point at which instability occurs, but rather a location related to the assemblage of objects with significantly different stiffness.
For example, if all or part of a structure is unsupported, no single point can be identified as missing support, so the software indicates that numerical instability occurs, and the point shown relates to the structural systems and solution convergence.