### CYL4, $l$, ${R}_{0}$, ${h}_{0}$, $\epsilon$, $i$

Creates a quarter-cylinder. Several CYL4 commands are not allowed. A combination with BLOCK and CYL2 commands is not allowed. Parameter $\epsilon$ adds an imperfection to the circular tube shape. Parameter $i$ defines the mode of imperfection ($i=2,3,\cdots$). The imperfection is set to be maximal in the middle of the tube and to be zero at its ends, which stay perfectly circular. The imperfection $\epsilon =0.01$ means $1\mathrm{%}$ of the diameter in the tube’s middle. The formulae used for imperfection calculation are described in Stembera2013.

Parameter Description
$l$ cylinder length
${R}_{0}$ cylinder inner radius
${h}_{0}$ cylinder thickness
$\epsilon$ imperfection
$i$ order of imperfection (default value is 2)