$(4)$ A thin$-$walled cone $($wall thickness $t)$ is supported on a horizontal base as Fig. C

shown in Fig. C and subjected to internal gas pressure $p_2$ Neglecting the weight of

the cone itself, find the principal membrane stresses ${}_1$ and ${}_2$ at the level $h$ below the

apex. The apex angle of the cone is $2$ as shown. Ans.

${}_1=\frac{phtan}{2tcos}$;$,{}_2=\frac{phtan}{tcos}.$