**Introduction:**

It shows the Lam´e’s line for the case of internal pressure.

**Description:**

If equations

are plotted with respect to a horizontal axis, where σ_{r}is the horizontal axis, the two equations appear as a single straight line, where (T, lies to the left and (T,

to the right, as shown by Figure

For the case shown in Figure

Figure: Lame line for the case of internal pressure.