Stress analysis of lattice composite cylinder under internal pressure and torsion

This paper focuses on stress analysis of lattice layer of a pressure vessel with cylindrical cross section. Lattice layer consists of helical and circumferential ribs made from glass/epoxy composites by using an automatic filament winding machine in a symmetric pattern. Actual loads of the structure are uniform internal pressure and torsion applied on the edges. Only longitudinal forces in the ribs are considered in this investigation. In a continual element of shell in two isolative variants, the effects of uniform internal pressure and torsion were considered to produce tensile and shear state of stresses, respectively. In each variant of loading, corresponding forces in ribs were analytically formulated with respect to loads. Acting stresses were determined in ribs and failure was controlled by maximum stress criteria. The extended analytical equations for forces in the ribs were applied to evaluate the local buckling of the structure as well as to obtain an equivalent elastic modules and Poisson’s ratio for the lattice layer.