About Deflection and Moment Lines (AutoCAD Mechanical Toolset)

The moment of inertia and deflection line functions are part of the calculation feature.

You can calculate moments of inertia for an object and use the result to calculate the deflection line or moment line (bending moment) for that object, when put under various acting forces.

The necessary data for calculating the defection line or moment line can be defined beforehand; you can set the type of material, define the supports for the object, and specify the forces acting on that object.

The resultant deflection line and moment line are presented graphically in the drawing; a table containing information about the calculation is also displayed.

The deflection line or moment line calculation is performed on a selected beam of an object that has various force elements acting on it.

Before you can calculate the deflection line of an object, you first calculate the moment of inertia for that object. You can then use the results to calculate the deflection or moment line (bending moment).

The general procedure for calculating the deflection line or moment line is as follows:

1. Define a cross section of the beam.
2. Calculate the moment of inertia for the cross section.
3. Specify a direction for the force acting on the cross section. The direction you specify determines the angle of deflection. After this, the moment of inertia block (value table) containing the result of the moment of inertia calculation is inserted into the drawing. The data in this table is necessary for calculating deflection lines and moment lines.
4. Define a cross section of the beam.
5. Calculate the moment of inertia for the cross section.
6. Start the AMDEFLINE command, and select the moment of inertia block.
7. Select the side view of the beam. A line that symbolically represents the side view is sufficient.
8. Define the supports, load forces, and type of material for the beam.
9. Start the calculation for the deflection line or for both the deflection and the moment line.
10. In the Select Graph dialog box, you can specify the resolution for drawing the deflection line or moment line curves.
11. Select a drawing scale for the deflection line or moment line. A table containing the main values obtained from the calculation is displayed in your drawing. This table is a block and can be inserted into the drawing.