Welcome to Fibersim 101, a step-by-step series of articles meant to familiarize new users with the key concepts of the software. We recommend starting with Part 1 and downloading the “Fibersim_101.zip” file at the bottom of that page in order to follow along with these exercises. If you need to go back to Fibersim 101: (1 of 14) Model Setup click here.
Rosettes are critical measuring tools used throughout Fibersim to define fiber orientations on the composite part. These reference or “datum” features use one of four mapping schemes to establish what the 0-degree direction is at any point on the laminate. Any number of rosettes (using any mapping types) can be created, but a minimum of one is required for a composite design. A single rosette is capable of defining all the fiber orientations on a given model.
A rosette is defined by a surface, an origin point on that surface, and a curve emanating from that point that defines its 0-degree direction. Once these characteristics have been established, that 0-degree direction can map itself to any other point on the laminate surface (to a Ply or Design Station origin, for example) based on the rosette’s mapping type.
Once mapped to any other point on the surface, the right-hand rule—based on the parent laminate surface’s normal direction—is used to measure any angle from that mapped 0-degree direction. This chapter will discuss the four different mapping types for rosettes, and what makes each of these types appropriate for different kinds of parts.
The Standard type of rosette mapping uses an algorithm that is based on part curvature. This is the most common type of rosette, and is appropriate for most part geometries such as simple monolithic and sandwich panels, or complex fairings and nacelles. As we will see later with the other types of rosette mapping, a Standard rosette may not be the best choice for domes, revolved surfaces, or C-channels/aircraft stringers.
1. In our example model, please create a standard Rosette by clicking on Rosette in Fibersim’s left-hand Applications tree. Right-click in the empty Rosette list that appears on the right, and select Create New.
2. Click the Link Geometry button next to the Origin field:
3. Click Point Dialog in the “Fibersim Point Selection Dialog” window that appears, as shown below:
4. Select Existing Point from the Type drop-down menu on the Point screen. Next, select the [ROSETTE ORIGIN] point as shown below, and then click OK twice to return to Fibersim.
5. Click Link Geometry button for Direction, and select the [ZERO DIRECTION] curve. Click OK to return to Fibersim.
6. Ensure that the Mapping Type is set to Standard, then click OK to complete the rosette.
Translational rosette mapping is most commonly used in roughly revolved shapes, such as the fuselage of an aircraft, where the design intent dictates that the 0-degree direction will always be parallel to the main axis (often the vehicle’s direction of travel).
A Translational rosette does a simple point-to-point translation of its 0-degree direction to any point of interest on the parent laminate surface. That direction curve is then projected down onto the laminate surface, and fiber orientations can be measured from there.
Typically for such revolved tool surfaces, an additional small, flat surface is created for the rosette along the axis of revolution. The Translational rosette’s origin and 0-degree direction curve are created on that surface (along the axis).
Radial rosettes are usually used for dome or dish-shaped parts. With the Radial type of mapping, the 0-degree direction is always radially outwards from the center of the part. Thus, a Radial Rosette is always placed in the exact center of the part.
Spine-Based rosette mapping is generally reserved for C-channel shapes, such as aircraft stringers. The design intent is for the 0-degree direction to follow the part’s spine. At any point of interest on the parent laminate surface, the 0-direction will be tangent to the rosette’s spine at the closest point.