Example: Extend Adjacent Surfaces
Consider the following model, with a shell pair created using a as the top surface and b as the bottom surface:
The adjacent solid surfaces cannot be extended to intersect the midsurface of shell pair a-b. Creo Simulate inserts additional cleave surfaces at the boundaries between the shell pair surfaces and the adjacent solid surfaces if you do not select the Extend Adjacent Surfaces check box. In this case, the solid-midsurface compression is as shown:
For the same model, when the Extend Adjacent Surfaces check box is selected, Solid / Midsurface compression fails, because extension of the adjacent surfaces cannot intersect the shell placement surface.
| For mixed compression to work for models created in Mechanica 4.0 and earlier releases you must clear the Extend Adjacent Surfaces check box if you have shell pairs with top and bottom surfaces tangent to their adjacent surfaces that are not marked for shell pair compression |
A variable thickness shell pair defined using the surfaces a and c as top surfaces and b and d as bottom surfaces is shown below:
If you select Extend Adjacent Surfaces Solid/Midsurface compression is as shown:
![](../../../../../simulate/simulate/images/i_exam_extend_adj_on.gif)
If Extend Adjacent Surfaces is not selected, compression fails because the additional cleave surfaces normal to the shell pair surfaces cannot intersect the shell placement surface.