Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

FEM: weak forms

  1. Oct 30, 2009 #1
    For a second order differential equation, is it necessary to derive a weak form if quadratic interpolation are used?
     
  2. jcsd
  3. Oct 30, 2009 #2
    For the weak form of a second order differential equation, both weighting function(w) & the primary variable(u) are required to have non zero first order derivatives(in order to define the stiffness matrix), ie linear approximation can suffice provided the problem allows. Linear elements will not provide interelement continuity though, hence continuity of secondary variables cannot be guaranteed . Quadratic elements provide SV continuity.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook