Curved Sections

Structural Design User Guide

Sections : Curved Sections

Each curved section is represented in the design model by a curved section (GENSEC) element. A GENSEC element comprises straight and curved segments and its geometry is defined by extruding a 2D catalogue profile along a path. The path lies on a plane and represented by a SPINE element, owned by the GENSEC, whose route is specified by a sequence of Spine Points (POINSP).

POINSPs are created at the start, the end and at each change of direction. Each segment linking adjacent spine points can be a straight line or circular arc achieved by inserting Curve (CURVE) elements.

GENSECs can be connected to each other or to SCTN elements, fixings and joints can also be applied to them.

A GENSEC element can be owned by a FRMW or a SBFR element and each element which makes up a GENSEC element has attributes unique to each of them.

GENSEC

A GENSEC can represent any component whose geometry is defined by sweeping a 2D profile along a linear or curved path (its SPINE element). It has a uniform cross-section along its length, defined by reference to a Catalogue Profile element. In its simplest form, where the Spine is defined as a line between two fixed points, the GENSEC can be used as an alternative to the SCTN element. In its more general form, where the Spine consists of a sequence of straight and/or curved segments, it can represent curved beams, curved walls, and so on.

SPINE

A SPINE defines the path through which a cross-sectional Profile must be swept to generate a GENSEC. The route of the Spine is defined by a sequence of Spine Points (POINSP): one at the start, one at the end, and one at each change of direction. Each segment linking adjacent Spine Points can be either a straight line or an arc of a circle: the latter is achieved by the insertion of a CURVE element,

POINSP

A POINSP element defines the start and end of a Spine path, and any location along the path at which there is a change of direction.

CURVE

A CURVE element defines a segment of a Spine path. It defines the geometry of the Spine between the POINSPs either side of it in the members list.

Create Curved Section

On the SECTIONS tab, in the Create group, click Create Sections, select Curved to display the Curved Section window.

All the tasks that the user would carry out with the creation of a curved section are initiated from a central Curved Section window, which acts as a task hub.

Create Methods

To create a curved section, the user can select one of eight creation methods from the Create Methods part of the Curved Section window.


	Free definition	Allows the user to select any number of points, at every change of direction, a fillet with the specified radius is included. The user is prompted to ‘Define curved section “free”<escape> to finish (Snap) Snap:’
	Right angle	The user must select 3 points at every change of direction, a fillet with the specified radius is included. If required the user can use the functionality displayed in the Positioning Control window. Before the user can make any selection a warning is displayed: ‘Spine definition MUST contain at least three points’ The user is prompted to ‘Define curved section “right angle” start (Snap) Snap’ Once the first selection has been made, the user is prompted to Define curved section “right angle” end of first leg (Snap) Snap’ Once the second selection has been made, the user is prompted to Define curved section “right angle” end of last leg (Snap) Snap’ The user must then select the final point, the right angled section is automatically created and displayed in the 3D view.
	Closed rectangle (fillet)	The user must select 3 points the specified radius is applied at each corner. If required the user can use the functionality displayed in the Positioning Control window. The user is prompted to ‘Define curved section “closed rectangle” start (Snap) Snap’ Once the first selection has been made, the user is prompted to Define curved section “closed rectangle” end of first leg (Snap) Snap’ Once the second selection has been made, the user is prompted to Define curved section “closed rectangle” end of last point (Snap) Snap’ The user must then select the final point, the closed rectangle section is automatically created and displayed in the 3D view.
	Open rectangle (fillet)	The user must select 3 points the specified radius is applied at each corner. If required the user can use the functionality displayed in the Positioning Control window. The user is prompted to ‘Define curved section “open rectangle” start (Snap) Snap’ Once the second selection has been made, the user is prompted to Define curved section “open rectangle” end of last point (Snap) Snap’ The user must then select the final point, the open rectangle section is automatically created and displayed in the 3D view.
	Swan neck	The user must select 3 points at every change of direction, a fillet with the specified radius is included. If required the user can use the functionality displayed in the Positioning Control window. The user is prompted to ‘Define curved section “swan neck” start (Snap) Snap’ Once the first selection has been made, the user is prompted to Define curved section “swan neck” end of first leg (Snap) Snap’ Once the second selection has been made, the user is prompted to Define curved section “swan neck” end of last leg (Snap) Snap’ The user must then select the final point, the swan neck section is automatically created and displayed in the 3D view.
	Obloid	The user must select 2 points to specify the centres of the two semi-circular ends of the obloid. A 3rd point must now be selected to specify from which point the start and end points of the straight sides originate. The specified radius is applied at each semi-circular end. If required the user can use the functionality displayed in the Positioning Control window.’ The user is prompted to ‘Define curved section “obloid” first centre (Snap) Snap’ Once the first selection has been made, the user is prompted to Define curved section “obloid” second centre (Snap) Snap’ Once the second selection has been made, the user is prompted to Define curved section “obloid” start/end side (Snap) Snap’ The user must then select the final point, the obloid section is automatically created and displayed in the 3D view.
	Closed rectangle (centre)	The user must select 3 points the specified radius and centre type curves are applied at each corner. If required the user can use the functionality displayed in the Positioning Control window. The user is prompted to ‘Define curved section “closed rectangle” start (Snap) Snap’ Once the first selection has been made, the user is prompted to Define curved section “closed rectangle” end of first leg (Snap) Snap’ Once the second selection has been made, the user is prompted to Define curved section “closed rectangle” end of last point (Snap) Snap’ The user must then select the final point, the closed rectangle section is automatically created and displayed in the 3D view.
	Open rectangle (centre)	The user must select 3 points the specified radius and centre type curves are applied at each corner. If required the user can use the functionality displayed in the Positioning Control window. The user is prompted to ‘Define curved section “open rectangle” start (Snap) Snap’ Once the second selection has been made, the user is prompted to Define curved section “open rectangle” end of last point (Snap) Snap’ The user must then select the final point, the open rectangle section is automatically created and displayed in the 3D view.

By default the Connect Ends? check box is not selected and the Radius of the curve is 1000mm.

To connect the end of the curved section, the user must select the Connect Ends? checkbox.

To modify the radius of the curve, input the radius into the Radius field.

The user must then select the a creation method from the Create Methods part of the Curved Section window, the Positioning Control window is also displayed. If required use the functionality available from the Positioning Control window to select how the points required to build the curve are selected in the 3D view.

Once the selection of all the required points have been made, the curved section is automatically created and displayed in the 3D view, with the exception of the Free definition method.