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Fibersim 101: (2 of 14) Laminates

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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.

 

Tool Surface

The layup or tool surface is the NX sheet body associated to the Laminate object in Fibersim. The requirements for any CAD surface to be used as a tool surface include:

  • It must be continuous within the defined laminate boundary.
  • It cannot have any discontinuities or holes in the region where the simulation will be run.
  • If sections of the surface have holes as part of a post machining of the part, or as part of the base layup, these holes must be filled in before running the simulation.

An important thing to note is that the CAD surface feature selected for the laminate must have its normal pointing in the direction of layup. In other words, the surface normal must point to the side of the surface where the components (plies and cores) and child laminates will reside. This is critical for the creation of laser projection data and other downstream functions.

Net versus Extended (Design Boundary)

Plies in Fibersim—which will be discussed in detail in a later section—are typically assigned a single boundary that is completely user-controlled (its design boundary), but will also have another boundary that is extrapolated (derived boundary). Traditionally, the Net or “as-flown” boundary is the design boundary and the Extended or manufacturing boundary is the one that is derived. This design approach is ideal for situations where designer wishes to focus on defining plies’ net shapes, while the extended boundaries are simply offsets of those net shapes. Fibersim automatically calculates the extended boundary for each ply by extending each selected net boundary curve to the parent laminate's extended boundary.

There are cases, however, where the laminate's net and extended boundaries have radically different shapes. In such scenarios, the correct extended boundary for each ply cannot be calculated simply by extending its net boundary to the parent laminate's extended boundary. This is where the "Design-to-Extended" design approach can be used to achieve the correct ply shapes. Specifying Extended as the laminate’s design boundary allows users to define plies to their extended boundary, and the net boundary will be derived by trimming each component back to the laminate's net boundary.

It’s important to note that once a laminate’s design boundary has been assigned (when the laminate is first created), the design boundary option becomes read-only and cannot be changed. When creating a laminate, both a net and an extended boundary are required, and all children will inherit its design boundary.

If the parent laminate’s design boundary is set to extended, all of its child plies’ boundaries, splice curves, and darts must be trimmed to the laminate extended boundary. Further, Holes defined in plies must be completely inside the parent laminate’s net boundary. Finally, child plies’ net geometry members will be read only, their net boundaries will not highlight, net producibility simulations cannot be run, and their net flat patterns cannot be generated.

1.) Please open the example model, select Laminate from the left-hand Applications tree, right-click in the empty list to the right, and select Create New.Laminates1.jpg

 

2.) In the “create Laminate” form, change the name to DUCT, and the Step to 1. Next, click the Link Geometry button next to Layup Surface as shown below:Laminates2.jpg

 

3.) In the NX graphics window, select the highlighted sheet body and click OK.Laminates3.jpg

 

4.) Click the Link Geometry button next to Net Boundary and select the curve shown. Then click OK.Laminates4.jpg

 

5.) Click the Link Geometry button next to Extended Boundary and select the curve shown. Then click OK.FibersimLaminates5.jpg

 

6.) On the right-hand side of the Standard tab of the “create Laminate” form is the choice for the Design Boundary (Net or Extended). Once the Laminate has been created, this option cannot be edited. In this case, we want to design plies to the laminate net boundary, so please leave the default Net selection. Click OK to save the new laminate.FibersimLaminates6.jpg

 

Sequence Order

Sequence and Step values are used to organize laminates and their child components (plies and cores) a logical manner. Laminates are typically given unique Sequence values, while their children should be assigned the same Sequence as their parents. Further, within this hierarchical framework, child components should be given Step values larger than the Step values of their parent laminates. Doing so denotes that a laminate’s children come “after” the laminate. Assigning Sequence and/or Step values to children “before” their parents (smaller values) would not make logical sense and will likely cause errors downstream in the Fibersim workflow.

FibersimLaminates7AscendingLayupDirection.jpg

 

 

 

 

 

 

 

 

 

 

 

 

Analysis

The Analysis tab of the “create/modify Laminate” form calculates the total combined center of gravity, weight, area, perimeter, and cost of child components. There are two sets of analysis data for each laminate: one for the net boundary and one for the extended boundary. To update these calculated values, the child plies’ net and extended producibility simulations must be up to date. If the part contains cores, analysis data must be entered in the core form to be properly reflected in net and extended analysis data. As core objects can be defined in a variety of ways, Fibersim does not automatically generate core analysis information; it is manually entered.FibersimLaminates8ModifyingLaminates.jpg

 

Continue to Fibersim 101 (3 of 14) Rosettes Now