Section Maker allows you to automatically create a number of sections, which interpolate between two existing sections. This can be used to model the changing sectional shape in a tapered member. Suppose you were modelling a tapered beam in Multiframe that started with a 12inch (300mm) deep section and tapered to a 24inch(600mm) deep section. You could draw the first section and install it in the library, then draw the second section and install it. To create the intermediate sections you use the Taper command from the Shape window.

To install a number of intermediate sections between to existing sections

§    Choose Generate Tapered Sections… from the Library | Sections submenu.

A dialog box will appear which allows you to select the start and finish sections

§    Click on the Start Section button

A dialog box will appear listing the available groups and sections

§    Click on the group and section names of the starting section

§    Click the OK button

§    Do the same for the end section.

The two sections you have chosen will be displayed in the dialog.

§    Type in the number of intermediate sections you want to generate

The sections properties will be calculated at the mid point of each subdivision of the range between the start and end sections. Section Maker makes an approximation to the intermediate section properties by interpolating between the properties at each end. All the properties except the moments of inertia and the torsion constant are interpolated linearly and will be exactly correct. The moments of inertia and torsion constant are interpolated using a cubic approximation to the variation in property along the tapering member. This will result in a small error in the moments of inertia and torsion constant but in most cases this should not impact significantly on your analysis. If you have a problem, which is sensitive to the value of torsion or moments of inertia, you should determine that this error will not have an adverse impact on your analysis. A quick check of the values at the mid-point will give you a guide to the maximum error.

§    Type in a name for the section

This name will form the basis of the names for the added sections. If "TestShape" is the name you give to the sections, the intermediate sections will be named TestShape1, TestShape2 … and so on up to TestShapen, where n is the number of intermediate shapes you requested.

§    If you want to remove the original start and end sections check the check box at the bottom of the dialog

Most times you will want to do this if you have drawn the sections as the original sections will not be used in the Multiframe analysis. The sections will only be deleted if the groups they belong to are not locked. To unlock a group, see Locking/Unlocking a Group on page 59.

§    Specify which group you wish to install the intermediate sections into

§    Click the OK button

If you want to view or change the properties of the sections which are created, you can view them in the Sections Tab in the Library Window (see Viewing Sections on page 65).

Note

Remember that whenever you install sections in the library using Section Maker, these new sections will only become available after saving the library and opening it in Multiframe.