...
Discretization
...
refers
...
to
...
the
...
process
...
of
...
translating
...
the
...
material
...
domain
...
of
...
an
...
object-based
...
model
...
into
...
an
...
analytical
...
model
...
suitable
...
for
...
analysis.
...
In
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structural
...
analysis,
...
discretization
...
may
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involve
...
either
...
of
...
two
...
basic
...
analytical-model
...
types,
...
including:
...
- Node-element
...
- model
...
- ,
...
- in
...
- which
...
- structural
...
- elements
...
- are
...
- represented
...
- by
...
- individual
...
- lines
...
- connected
...
- by
...
- nodes.
...
- In
...
- a
...
- 3D
...
- system,
...
- each
...
- node
...
- has
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- six
...
- degrees
...
- of
...
- freedom,
...
- each
...
- either
...
- constrained
...
- or
...
- free.
...
- The
...
- geometric
...
- and
...
- material
...
- properties
...
- of
...
- structural
...
- elements
...
- are
...
- then
...
- characterized
...
- by
...
- line
...
- elements
...
- which
...
- simulate
...
- their
...
- physical
...
- behavior
...
- by
...
- following
...
- mathematical
...
- relationships.
...
- Through
...
- application
...
- of
...
- the
...
- direct
...
- stiffness
...
- method,
...
- loading
...
- at
...
- node
...
- locations
...
- translates
...
- into
...
- displacement
...
- and
...
- stress
...
- fields
...
- which
...
- indicate
...
- structural
...
- performance.
...
- Finite-element
...
- model
...
- ,
...
- in
...
- which
...
- a
...
...
- procedure
...
- creates
...
- a
...
- network
...
- of
...
- line
...
- elements
...
- connected
...
- by
...
- nodes
...
- within
...
- a
...
- material
...
- continuum.
...
- Each
...
- line
...
- element
...
- simulates
...
- the
...
- geometric
...
- and
...
- physical
...
- properties
...
- of
...
- the
...
- local
...
- material.
...
- Given
...
- the
...
- loading
...
- and
...
- boundary
...
- conditions
...
- of
...
- the
...
- whole
...
- system,
...
- numerical
...
- formulation
...
- of
...
- structural
...
- response
...
- may
...
- advance
...
- through
...
- the
...
- computational
...
- model.
...
- The
...
- discretization
...
- of
...
- a
...
- finite-element
...
- model
...
- will
...
- have
...
- some
...
- degree
...
- of
...
- refinement,
...
- producing
...
- either
...
- a
...
- coarse
...
- or
...
- fine
...
- mesh.
...
- A
...
- node-element
...
- model
...
- is
...
- technically
...
- a
...
- finite-element
...
- model
...
- in
...
- which
...
- a
...
- single
...
- line
...
- element
...
- represents
...
- the
...
- structural
...
- element.
...
- Node-element
...
- modeling,
...
- however,
...
- follows
...
- the
...
- direct
...
- stiffness
...
- method,
...
- whereas
...
- finite-element
...
- modeling
...
- follows
...
- the
...
- (FEM).
...
- The
...
- SAPFire ® Analysis Engine implements an efficient finite-element
...
- approach
...
- when
...
- performing
...
- structural
...
- analysis.
...
Division of frame elements
While the discretization of an object-based
...
model
...
is
...
always
...
critical
...
(in
...
that
...
discretization
...
facilitates
...
analysis),
...
there
...
are
...
conditions
...
in
...
which
...
it
...
is
...
also
...
important
...
to
...
divide
...
frame
...
elements
...
into
...
multiple
...
segments
...
such
...
that
...
accurate
...
results
...
are
...
generated.
...
It
...
is
...
useful
...
to
...
subdivide
...
frame
...
elements
...
for
...
the
...
following
...
analysis
...
types:
...
- Buckling analysis - To capture higher modes.
- P-Delta (P-δ)
...
- effect
...
- -
...
- To
...
- better
...
- capture
...
- local
...
- column
...
- deformation
...
- for
...
- assessment
...
- of
...
- equilibrium
...
- conditions
...
- about
...
- displaced
...
- configuration.
...
- Displacement
...
- accuracy
...
- -
...
- To
...
- create
...
- joints
...
- at
...
- locations
...
- where
...
- accurate
...
- displacements
...
- are
...
- needed,
...
- otherwise
...
- values
...
- are
...
- interpolated
...
- from
...
- the
...
- nodes
...
- at
...
- either
...
- end
...
- of
...
- the
...
- frame
...
- element.
Discretization tips
- For shell elements, discretization may be refined through auto meshing (Assign > Area > Automatic Area Mesh) or area dividing (Edit > Areas > Divide Areas).
- For frame elements, auto meshing at intermediate points is specified by default. Frame discretization is then connected to that of shell elements at each applicable joint.