Hello,

I’m trying to plot the stresses in colour of a strained isoparametric element.

I have a six noded triangle with vertice coordinates [(xa1,ya1),(xa2,ya2),(xa3,ya3)] = pos_a

This triangle deforms and the new coordinate positions are [(xb1,yb1),(xa2,yb2),(xb3,yb3)] = pos_b

The remaining nodes are mid nodes also with rest and deformed coordinate positions.

To plot the edges of the triangle I use a Jacobian transformation function so that the coordinates of the triangle are in Jacobian coordinates xi1 and xi2 (with xi3 = 1 - xi1 - xi2). This is required as the elements are quadratic with mid-nodes.

Each interval is hard coded so that:

xi1 = [1.0,0.9,0.8,0.7,0.6,0.5, etc…]

xi2 = [0.0,0.1,0.2,0.3,0.4,0.5, etc…]

I would like to plot the strains in colour so that the interior of the triangle is filled but I don’t want to hard code the Jacobian intervals as this seems an awkward way of doing it.

With strain as a function of xi1 and xi2, How can matplotlib provide a continuous interior strain plot of the triangle for all the xi1 and xi2 values from 0 to 1?

Regards

Alex Naysmith

My finite element program can be downloaded from here: http://www.pynw.org.uk/Talks?action=AttachFile&do=view&target=2D_FEA.zip