An experimental and numerical investigating into the effect of stiffeners on the behavior of grid cylindrical composite shells with elliptical cutouts under axial compression

This paper presents experimental and numerical investigation of the effect of the stiffeners on the stress analysis of grid cylindrical composite shells with elliptical cutout under axial compression. Grid cylindrical composite shells are combination of shell and stiffeners. These structures are widely used in aerospace industries and especially in missile nose, so they are often subjected to axial loading. There are many papers dealing with stress distribution of unreinforced composite cylindrical shells subjecting to different types of loading while there are very few literatures concerning the stress analysis of grid cylindrical composite shells with cutouts or stress concentration of these structures. In this research the effect of the stiffeners on stress distribution and stress concentration factor were carried out. Filament winding machine is used to manufacture them, then strain gauges were used for measuring amount of strain and consequently stress gradient is obtained. Strain gauges were attached in outer side of the shell near cutouts to stiffeners in two directions to investigating the values of principle stresses on the shells. The numerical modeling of structure is carried out by ABAQUS commercial software and results of two methods are compared.