Finite Element Methods (global stiffness matrix)

[eWizardII]

Homework Statement

I have the following practice problem which is presented as follows:

What is the size of the global stiffness matrix K (i.e., Kuu) for the 2-D problem?

http://imgur.com/KZec3 (Unsolved)

http://imgur.com/piv1J (Solved)

Homework Equations

The Attempt at a Solution

So in the solved problem which I think I did right I counted the total number of nodes which is 12, since each has 2 degrees of freedom the size of the matrix is 24 x 24? Does this sound correct?

If so now I attempt the other problem, where the ? I think should just be theta's but I believe there was a rendering problem. Anyways my attempt would be again count the number of nodes in which case there are 15 nodes. And again the nodes have a total of 2 degrees of freedom so this is a 30 x 30 size matrix?

Does this sound correct? (there are few problems with which to practice this one, so I'm trying to understand the methodology here for an exam, so any insight would be helpful)

 

[mdn]

the size of Global stiffness matrix = nodesxnodes.