Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Laminate modeling with Advanced shells?

Laminate modeling with Advanced shells?

Laminate modeling with Advanced shells?


I am trying to model a simple rectangular plate (with three layers) using the advanced shell feature.  What should the proe  model be before I use the shell?  (a solid or a surface?)... I tried the surface model but I am having "insufficiently constrained model errors" when I run it.  This is a simple plate (load in the middle) and clamped at both ends.
Thanks for sharing your tips.

RE: Laminate modeling with Advanced shells?


You should use a surface.  The laminate idealization pertains to shells.

Keep in mind that shells have 6 degrees of fredom.  So if you are constraining 1 edge of your shell you will need to specify both translational and rotational constraints.

Good luck,



RE: Laminate modeling with Advanced shells?

You can use either a surface or a solid. If you use a solid then you have to pick the surface of the solid that you use as the shell. Either way you end up with just a surface for the FEA so you have to constrain it just like Steve said. The only time I use solids with laminates is if I intend to have mixed mesh models (solid and shell elements).

RE: Laminate modeling with Advanced shells?

Unless your plate is very thick, solids should be avoided.
Usually one uses solids if shear plays an important role and you need to know what happens in the core. But I believe this is not your case; besides the constraints will differ if you apply them on solids rather than on shells; then for a mixed structure you have to be aware of where you are applying them .

But why do you clamped both sides ? Do you really need to study an overconstraint structure ?


RE: Laminate modeling with Advanced shells?

flyerfly, some time ago you've mentioned, that you have assigned a moving coordinate system to follow the curvature of the part (in Nastran). Do you have such experience with Mechanica?

RE: Laminate modeling with Advanced shells?

Yes I do this all the time.

Mechanica has the following options for material orientation on shells.

1. Referenced Coordinate system
2. First Parametric direction
3. Second Parametric direction
4. Projected vector

All surfaces have "direction curves" so you can assign the coordinates to follow these if you wish. I don't use projected vector much because if the surface has alot of curvature then you will have errors if the projected angle is to much. I use the parametric directions most of the time on curved surfaces.

You can find these options under "material orientation" in the shell properties.

If you are going to use laminates in Mechanica you need to have advanced mechanica, not just the regular one. Hope this helps.


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close