If used carefully, the feature-based modeling approach used by Abaqus/CAE allows you to capture both your design and analysis intent.
Design intent is the capability to make changes based on design considerations. For example, when you add a cut feature, you can select either a through cut or a blind cut. If the cut feature represents a bolt hole, you know that the hole must always pass completely through the part. As a consequence, you should select a through cut, and Abaqus/CAE recognizes that the hole remains through even when you change the thickness of the part.
Analysis intent is the capability to make changes based on analysis considerations. Although Abaqus/CAE allows you to create parts with complex, detailed geometry, your final goal is usually a finite element analysis of a meshed representation of the part. Excessive detail, such as fillets and small holes, can lead to regions with a very fine mesh that will, in turn, dominate the time taken by Abaqus/Standard or Abaqus/Explicit to reach a solution. The amount of detail you provide when you create a part in the Part module should be a reflection of your goals. Alternatively, you can create a part with detailed features but suppress them prior to meshing the assembly. For example, if a model takes several hours to analyze, you may wish to simplify it by suppressing features; you could then submit an analysis that runs faster and checks your basic modeling assumptions. If the simplified model behaves as expected, you can unsuppress the features and resubmit a full analysis.
For an example of different feature-based design approaches based on design and analysis intent, consider the cover plate shown in Figure 11–42.
You could create the three-dimensional shell that models the plate in several ways:Sketch a base feature that includes the four holes.
Sketch a rectangular base feature, and add four separate cut features.
Sketch a rectangular base feature, and add a single cut feature that cuts all four holes.
Do you want to create and analyze plates of varying sizes with different sized holes for different applications? If the diameter of all four holes is always identical, you should create all four holes as a single cut feature. However, if the diameter of individual holes might differ, you should create four separate cut features.
Do you want to suppress features before you finalize your design? For example, you could perform a series of analyses with the holes suppressed to determine the desired plate thickness. You could then unsuppress the holes and analyze the finished model. In addition, suppressing features may simplify the mesh that Abaqus/CAE generates, or suppressing features may make the assembly sweep meshable.
If you want to suppress all four holes in the example of the rectangular cover plate, you should create all four holes as a single cut feature. However, if you want to suppress individual holes, you should create four separate cut features. If the analysis is straightforward and you do not need to analyze a simplified model, you should sketch a base feature that includes the four holes.
