Tab ATHENA > Group Extras > Center of gravity and moments
Menu:
ATHENA > Engineering > Center of gravity and moments
Toolbar:
ATH Engineering > Center of gravity and moments ATHENA Functions > Center of gravity and moments
Command input:
ath_schw
With this command you can compute centers of gravity and static moments of an individual profile or of a number of combined profiles. With combined profiles you must specify a composite structural coefficient to define the composition quality.
The program computes or dimensions the following values:
• Moments of inertia (lx, ly)
• Section moduli (Wx, Wy)
• Radii of inertia (lx, ly)
• Spacings to centroid axis (ex1, ex2)
• Center of gravity
• Area (A)
• Outer contour
• Weight/material
ath_schw
Center of gravity and moments of profile sections
Input request
Profile 1
Select outline or [?]:
Click the outer or inner outline of the first profile.
Input ENTER to terminate the program.
With the option ? you call the help.
Profile 1
Add outline or [Undo/?]:
Click another outer or inner outline of the first profile.
With the option Undo the previous input request is repeated.
This input request is repeated until you change to the next input request with Enter or a right click.
Profile 2
Select outline or [?]:
Click an outer or inner outline of the second profile.
The input requests are repeated as described above for further outlines and profiles. Once you have selected the last profile outline, input Enter to take you to the next input request.
Enter composite structural coefficient or [?] <0.7>:
Input Enter to accept the default value. The Dialog box Center of gravity and moments opens where you can view the results of the computation and carry out further settings.
Dialog box Center of gravity and moments
db_ath_schw
Dialog box section Moments of inertia
With ref. to centroid axes Outputs the moments of inertia (Ix and Iy) referred to the centroid axes in the results table.
With ref. to principal axes Outputs the moments of inertia (I1 and I2) referred to the principal axes in the results table.
Principal axis position Outputs the position of the principal axis in the results table.
Outputs the section moduli (Wx and Wy) in the results table.
Dialog box section Radius of inertia
Outputs the radius of inertia (ix and iy) in the results table.
Dialog box section Spacings to centroid axis
Outputs the spacing to the centroid axes in the results table.
Dialog box section Cross-section
Outer contour Outputs the circumference of the outer outline in the results table.
Total area Outputs the total area in the results table.
Dialog box section Material
Outputs the selected material in the results table. Choose the appropriate material from the list. Only materials are offered when the density is defined in the physical values. You will find further information on materials in the sections Material and Physical values.
Weight Outputs the weight (depending on the selected material) in the results table.
Dialog box section Insert
Text Inserts a results table into the drawing.
Dimensions Dimensions the distance from the outline outer edge to the principal axes.
Principal axes Draws the principal axes in the outline.
Update Updates an existing table, which you have to select.
If you click OK with the option Text activated, the following input request appears.
Input requestwhen text is switched on.
Specify insertion point:
Specify the insertion point of the results table.
Specify rotated angle or <0>:
Determine the rotation angle of the results table.
Input Enter to accept the default value.
Input requestwhen update is switched on.
Select table for update or [?]:
Select an existing table to update it.
Composite structural coefficient
The composite structural coefficient reduces the Steiner component in the computation. Consequently, the composite structural coefficient has no effect on the result when the computed profiles have the same center of gravity. The composite structural coefficient enables you to define the shear strength of various profiles - e.g. composite structural coefficient 1 = shear resistant (rigid) joint (profiles are welded all round). Composite structural coefficients for manufactured profiles must be obtained from the manufacturer.
Note
• The cross sections to be computed must be drawn in the scale of 1:1.
• The outer and inner contours of the various cross-sections must be circles or polylines (also in blocks). Polylines should be closed. Unclosed polylines are "virtually" closed for the computation. This can lead to inaccurate results.
• With the outline definition of the individual sections (inner or outer outlines) they are displayed in different colors.
• The texts in the value table are saved in multiple languages. You can display the text in another language with the command Set text language.
• You will find information on materials in the Chapter Material.
Note: This function for the calculation of structural analytical values is an aid for the user. CAD-PLAN GmbH can in no way be held liable for the results and any errors and losses arising from it.
