×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

fem Weak form and shape functions

fem Weak form and shape functions

fem Weak form and shape functions

(OP)
Good evening, I began to study the finite element method and I wanted to understand why it reduces the strong formulation of a degree to get to the weak.
Then I wanted to know what degree should have the shape functions? depending on what I choose it? And the system of algebraic equations and 'solvable even if non-linear? thanks to all

RE: fem Weak form and shape functions

These are fundamental questions.

The weak form allows for the underlying differential equation(s) to be solved numerically using Gaussian quadrature. Search Galerkin Method.
Think of shape functions as interpolation functions. They must satisfy certain continuity constraints, but they can be up to whatever order. Search p-method
I think your "algebraic equations" may refer to the standard way of visualizing the segmentation of stiffness matrix, displacement and force vectors into a conceptually tractable way, based on BCs.

FEM requires many mathematical preliminaries in order to understand how it works.
If it is helpful, think of the strong form as the exact differential equation, and the weak form as an integral equation.
For an exercise, try transforming the 1D heat equation with prescribed BCs to the weak form.

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!


Resources