Optimization of geometric parameters of latticed structures using genetic algorithm

Abstract

Purpose

The purpose of this paper is to analyze a squared lattice cylindrical shell under compressive axial load and to optimize the geometric parameters to achieve the maximum buckling load. Also a comparison between buckling loads of a squared lattice cylinder and a solid hollow cylinder with equal weight, length and outer diameter is performed to reveal the superior performance of the squared lattice cylindrical shells.

Design/methodology/approach

A cylindrical lattice shell includes circumferential and longitudinal rods with geometric parameters such as cross‐section areas of the rods, distances and angles between them. In this study, the governing differential equation for buckling load which can be presumed as a criterion for designing lattice structures with a specific weight is derived and is used as an objective function in genetic algorithm (GA) method to calculate the optimum geometric parameters of the shell. The optimum parameters were modelled in finite element method (FEM) in order to verify the buckling loads obtained from GA. In another effort, the FEM was applied to analyze the solid hollow cylinders.

Findings

The results demonstrate relatively close agreement between the buckling loads obtained from GA and FEM for such shells. It was also shown that latticed cylinders have better performance to carry compressive axial loads than the equivalent solid hollow cylinders with equal weights, lengths and outer diameters.

Research limitations/implications

The studies reported in this paper have been carried out for a single squared lattice shell without using two‐side skins. However, using skins can give better performance in carrying compressive axial loads.

Practical implications

The results in this paper show that this type of effective, economical lightweight and functional structures could be applied as inter‐stages, inter‐tanks, aircraft fuselage, rocket motor cases, pressure vessels and other elements of civil engineering structures in order to have greater strength and lower weight.

Originality/value

Squared lattice cylindrical shell with optimum geometric design could provide the chance for eliminating the stiffeners of shells in aerospace structures in order to decrease the weight and increase the load‐bearing capacity.

Citation

Hashemian, A.H., Kargarnovin, M.H. and Jam, J.E. (2011), "Optimization of geometric parameters of latticed structures using genetic algorithm", Aircraft Engineering and Aerospace Technology, Vol. 83 No. 2, pp. 59-68. https://doi.org/10.1108/00022661111120944