Static Moments¶
General¶
For the static verification of components in load-bearing structures, component cross-sections require the results of the moment of inertia, the moment of resistance and also the cross-sectional area.
For simple cross-sections and cross-sections of standardised profiles, you can also obtain this data from the relevant data tables.
These ELITECAD functions calculate the required data in the simplest possible way for in-house constructions and for composite cross-sections - combined with several standard profiles.
The toolbar for the static moments can be found under INFORMATION > MOMENTS.
Moments of inertia - Moments of resistance¶
Before you open the function, you should have completed the cross-section contour to be calculated.
The cross-section to be calculated can consist of several samples, and any number of recesses.
The pen and line types of the individual contour elements can be different. The contours to be specified do not have to represent closed lines. An open contour can be defined by entering points with the cursor and CLOSE POLYGON.
With the function INFORMATION > MOMENTS this window appears:
All icons explain their function with tooltips.
Start the calculation¶
With START , you are requested to select the outer contours of the cross-sections to be calculated (outside the contour) with the cursor. Any recesses are then indicated. These are tapped with the cursor within the recess contour. Each specified contour is highlighted with a dashed line as long as the MOMENTS function is active. This makes it easy to check which contours have already been defined for the calculation.
ATTENTION
Outside contours should always be selected on the outside and inside contours always on the inside.
End of calculation¶
Once all the contours concerned have been defined, the END function is used to terminate the input and the calculation is started automatically. The calculated values are output according to the set output parameters.
In SETTINGS > OPTIONS > WORK PARAMETERS > MECHANICS, select whether you want to output the results
- shown in the information window of ELITECAD.
- placed as a table (CAD object) on the drawing.
- saved as an ASCII file to be checked at a later time.
All units of measurement refer to the units currently set in ELITECAD.
The following values are calculated:
- Cross sectional area
- Circumference
- Centre of gravity coordinates
- Static moments
- Principal moments of inertia
- Moment of inertia in relation to the centre of gravity
- Angle of twist
- Moment of resistance
Note
Inaccuracies of up to 1% in the moments of inertia and resistance as well as the position of the main axes can occur.
Wmin and Wmax are sometimes interchanged.
The static moment relates to the X and Y axes through the screen centre point X0, Y0 (not the reference point)!
Draw axes of inertia¶
With this function, the main and minor axes for the moment of inertia and the moment of resistance are displayed on the screen as a separate CAD model.
The axes are drawn with pen 1 and line type 9.
The current text parameters are used for the designation of the inertia axes.
Note
Inaccuracies of up to 1% in the moments of inertia and resistance as well as the position of the main axes can occur.
Area calculation¶
Start the calculation¶
As with the calculation of moments of inertia, pressing START prompts you to select the outer contours of the cross-sections to be calculated (outside the contour) with the cursor. Any recesses are then indicated. These are tapped with the cursor within the recess contour. Each specified contour is highlighted with a dashed line as long as the AREA CALCULATION function is active. This makes it easy to check which contours have already been defined for the calculation.
ATTENTION
Outside contours should always be touched on the outside and inside contours always on the inside.
End the calculation¶
Once all the contours concerned have been defined, the END function is used to terminate the input and the calculation is started automatically. The calculated values are output according to the set output parameters.
In SETTINGS > OPTIONS > WORK PARAMETERS > MECHANICS, select whether you want to output the results
- shown in the information window of ELITECAD.
- placed as a table (CAD object) on the drawing.
- saved as an ASCII file to be checked at a later time.
All units of measurement refer to the units currently set in ELITECAD.
The following values are calculated:
- Cross sectional area
- Circumference
- Centre of gravity coordinates
CAD variables¶
All calculated values are temporarily saved in CAD variables so that they can be used directly for user macros.
| List of assigned CAD variables: | |
|---|---|
| &FLAECHE * | Area of the defined cross-section |
| &UMFANG * | Circumference of the defined cross-section |
| &MSPNTX * | X-coordinate of the centre of gravity |
| &MSPNTY * | Y coordinate of the centre of gravity |
| &MHx | Static moment |
| &MHy | Static moment |
| &MIx | Moment of inertia |
| &MIy | Moment of inertia |
| &MIxy | Moment of inertia |
| &MIm | Moment of inertia centre of gravity |
| &MIc | Moment of inertia centre of gravity |
| &MImc | Moment of inertia centre of gravity |
| &MPhi | Twist angle |
| &MI1 | Main moment of inertia |
| &MI2 | Main moment of inertia |
| &MWnmin | Moment of resistance relative to axis n-n |
| &MWnmax | Moment of resistance relative to axis n-n |
| &MWcmin | Moment of resistance relative to axis c-c |
| &MWcmax | Moment of resistance relative to axis c-c |
| &MW1min | Moment of resistance relative to axis 1-1 |
| &MW1max | Moment of resistance relative to axis 1-1 |
| &MW2min | Moment of resistance relative to axis 2-2 |
| &MW2max | Moment of resistance relative to axis 2-2 |
| &MXminn | Edge fibre spacing (X-negative) relative to axes n,c |
| &MXmaxn | Edge fibre spacing (X-positive) relative to axes n,c |
| &MYminn | Edge fibre spacing (Y-negative) relative to axes n,c |
| &MYmaxn | Edge fibre spacing (Y-positive) relative to axes n,c |
| &MXminc | Edge fibre spacing (X-negative) relative to axes 1,2 |
| &MXmaxc | Edge fibre spacing (X-positive) relative to axes 1,2 |
| &MXminc | Edge fibre spacing (Y-negative) relative to axes 1,2 |
| &MXmaxc | Edge fibre spacing (Y-positive) relative to axes 1,2 |
All variables marked with * are also assigned with the AREA CALCULATION function.