So, good afternoon everyone.

We would like to continue now our last exercise here, which is maybe resembling an examination.

And we stopped here, so 14.2 is a couple of questions concerning theory.

The first question is what does isoparametric concept mean?

What does it mean?

I think it was the method we used to transform from lobe to lobe.

It has something to do with that, yes.

When we transformed the distribution lobe, from lobe to lobe, did we do that?

No, no.

Basically, the number of the individual is always different, it is possible to do that.

It is important to differentiate them.

I think the previous question is in the step where we take x times u in terms of shape of it.

I think that is the first part of the question.

Basically, from the individual to the lobe.

And what is precisely the isoparametric concept?

There were...

Yes, check it please, check it.

And if you have checked it, you should in any case put it in your handwritten formula.

Yes, yes, yes.

So, A...

So, that's it.

Okay.

B is sketch an inadmissible bilinear quadrilateral element and explain why this is not admissible without computation.

Please think about that maybe two minutes and then we discuss the result.

Say it once again please.

No.

First question, what is the

Say it once again please.

It has an effect of course on the solution but the question is whether it does really

necessary to a failure of the computation.

Anyone else an idea?

Tell me.

You're going in the right direction.

There is a specific definition for an element that is not admissible.

If you're not sure you if you have your notes or the sample solution for the tutorial available

then you should have a look there we discussed that already.

Yes, it has something to do with the tracobion.

What does it mean if the tracobion is positive then what consequence does this have?

But what is the answer?

It's only partly.

Yes.

So maybe let me pose a question like this.

If the tracobion is positive, the determinant of tracobion is positive then the element is admissible.

Yes.

So an element is admissible if the determinant of the tracobion is positive.

Okay, one aspect.

But the question is we should sketch an inadmissible element and a bilinear quadrilateral element specifically here.

So how would an inadmissible quadrilateral element look like?

So here two edges are parallel.

Can you sketch it please?