Structure TypeFunction
Enter the type of and the basic data for structural analysis.
Call
From the Main Menu select Model > Structure Type.
Select Configuration > Structure Type from the Menu tab of the Tree Menu.
Entry
Structure TypeSelect an option as to whether the analysis is to be carried out in 3-D or 2-D.
3-D: 3-D structural analysis
X-Z Plane: 2-D analysis in GCS X-Z plane
Y-Z Plane: 2-D analysis in GCS Y-Z plane
X-Y Plane: 2-D analysis in GCS X-Y plane
Constraint RZ: 3-D analysis constraining rotational degree-of-freedom about GCS Z-axis
Note
6 degrees-of-freedom are considered by default for each node when constraints
are not defined by the user.
Use the function to exclude unnecessary degrees-of-freedom to ensure the efficiency of the analysis. Quite often, only 2-D behaviors or behaviors with a particular degree-of-freedom constrained are of interest.
3 - D
6 degrees-of-freedom per node applicable for a general 3-D structural analysis.
X - Z
Plane
2-D structural analysis on the GCS X-Z plane. (The Y-direction displacements
and the rotations about the X and Z-axes are automatically constrained.)
Y - Z
Plane
2-D structural analysis on the GCS Y-Z plane. (The X-direction displacements
and the rotations about the Y and Z-axes are automatically constrained.)
X - Y
Plane
2-D structural analysis on the GCS X-Y plane. (The Z-direction displacements
and the rotations about the X and Y-axes are automatically constrained.)
Constraint
RZ
Special 3-D analysis constraining the rotation(torsion) about the vertical
GCS axis (GCS Z-axis). The analysis may be applied to a preliminary design
of a structure, such as to analyze a lateral shear force distribution
for each story.
Conversion of Structure Self-weight into MassesPlace an option whether to convert the model self-weight into lumped masses for dynamic analysis
Do not convert: Do not convert into lumped masses.
Lumped Mass: Convert into lumped masses.
Convert to X, Y, Z: Convert the self-weight into lumped masses in the GCS X, Y, Z-directions
Convert to X, Y: Convert the self-weight into lumped masses in the GCS X, Y-directions
Convert to Z: Convert the self-weight into lumped masses in the GCS Z-direction
Note
The masses of the elements included in the model can be automatically converted
into lumped masses in MIDAS/Gen for dynamic analysis or computation of
statically equivalent seismic loads.
When dynamic analysis is performed
with “Do not convert” option checked, mass effect cannot be reflected
in the analysis.
If 'Convert to X, Y, Z' is selected, the mass, which is the weight divided by the acceleration of gravity, is automatically considered in the GCS X, Y, Z-directions. The weight itself is automatically obtained by multiplying the volumetric weight (density) entered in Model > Properties > Material by the volume of the element.
If 'Convert to X, Y' is selected, the calculated mass is automatically considered in the GCS X, Y-directions.
If 'Convert to Z' is selected, the calculated mass is automatically considered in the GCS Z-direction.
In most cases of building structures, lateral behaviors are more important than vertical behaviors. Thus, the vertical components of masses are commonly neglected. The condition of 'Convert to X, Y' saves analysis time and lessens the burden of computer memory capacities.
Where structures are analyzed considering only the vertical component of the seismic data or dynamic analyses are required to evaluate machine vibrations on floor slabs and other vertical vibrations, 'Convert to Z' may be more appropriate. The notion is identically applied when masses are generated by "Nodal Masses" or "Load to Masses".
For line elements (truss element, tension element, compression element, beam element), each element mass is divided by two and distributed to both ends as lumped masses.
For plane elements (plane stress element, plate element) and solid elements, each element mass is divided by the number of nodal corners and lumped to each node as lumped masses.
Self weight cannot be converted into mass in Load to Mass. It must be converted in Structure Type.
Gravity accelerationEnter the acceleration of gravity considering the unit system in use.
Initial TemperatureEnter the initial temperature required for a thermal stress analysis.(Refer to Load > System Temperature or Nodal Temperature)
Align Top of Beam Section
with Floor (X-Y Plane) for Panel Zone Effect/DisplayAlign the tops of line elements in the GCS X-Y plane such that their top elevations line up at the floor level (nodal positions of columns) when reflecting rigid offsets or displaying the elements in the Model Window. (Refer to "Rigid Offset Distance")
Note
In order to see Panel Zone Effect applied, “Auto Calculate Panel Zone Offset
Distances” should be defined first in Model > Boundaries > Panel Zone Effect.
Align Top of Slab (Plate)
Section with Floor (X-Y Plane) for DisplayAlign the tops of plate elements in the GCS X-Y plane such that their top elevations line up at the floor level (nodal positions of columns) when displaying the elements in the Model Window.
Note
When the alignment options are not selected, the centerlines of the line and plate elements are shown to be connected to the column nodes.