Optimal design of general stiffened composite circular cylinders for global buckling with strength constraints

Abstract

A design strategy for optimal design of composite grid-stiffened cylinders subjected to global and local buckling constraints and strength constraints was developed using a discrete optimizer based on a genetic algorithm. An improved smeared stiffener theory was used for the global analysis. Local buckling of skin segments were assessed using a Rayleigh-Ritz method that accounts for material anisotropy. The local buckling of stiffener segments were also assessed. Constraints on the axial membrane strain in the skin and stiffener segments were imposed to include strength criteria in the grid-stiffened cylinder design. Design variables used in this study were the axial and transverse stiffener spacings, stiffener height and thickness, skin laminate stacking sequence and stiffening configuration, where stiffening configuration is a design variable that indicates the combination of axial, transverse and diagonal stiffener in the grid-stiffened cylinder, The design optimization process was adapted to identify the best suited stiffening configurations and stiffener spacings for grid-stiffened composite cylinder with the length and radius of the cylinder, the design in-plane loads and material properties as inputs. The effect of having axial membrane strain constraints in the skin and stiffener segments in the optimization process is also studied for selected stiffening configurations.

On the Planning and Design of the Utilization Efficiency of College Gymnasiums in Jiangsu

“…Therefore, demands grow for colleges and universities to step up efforts to remedy the situation of insufficient infrastructure (Jaunky et al, 1998). In terms of extracurricular activities, demands outstrip the venue supply of popular sports events such as basketball, table tennis, and badminton.…”

Buckling Analysis of Grid-Stiffened Composite Shells

“…Weber and Middendorf [18] integrated the interaction between adjacent skin fields into the calculation of the local skin buckling load by applying periodic boundary conditions at opposite panel edges. Both global and local buckling behaviours were considered in a weight-minimum design for grid-stiffened panels and cylinders using a genetic algorithm [19,20]. In the work, an improved smeared theory with the offset effect of stiffeners included [21] was employed for the global analysis, while the local skin buckling was assessed by the Rayleigh-Ritz method which accounts for material anisotropy and stiffener crippling was assessed using the method provided in Reddy's work [6].…”

Experimental, numerical and analytical investigation of free vibrational behavior of GFRP-stiffened composite cylindrical shells

“…The selection of stiffener configuration depends on several factors such as the loading condition, cost, and other factors. The promising future of stiffened cylinders with reinforcing grids or ribs, has led to a wide range of research work [30][31][32][33][34][35][36][37][38].…”