BY-NC-NDGašić, MilomirSavković, MileBulatovic, Radovan2020-09-192020-09-1920110039-2480https://scidar.kg.ac.rs/handle/123456789/9678The cross sections of truck crane booms are complex box-like cross sections, which should provide continuous stress allocation. It is difficult to analytically determine optimal relations among geometric parameters of such cross sections. The paper deals with the method for determining relations among geometric parameters in order to achieve the optimal shape of the cross section. The method is based on Lagrange's multipliers used for determination of extreme values. The optimisation of geometric parameters has also been done with the method of differential evolution (DE). The optimisation of the cross section is based on the strength criterion. The results of the applied methods have been verified by means of numerical example for an existing solution. The comparative analysis of the results of both methods has also been done. © 2011 Journal of Mechanical Engineering. All rights reserved.openAccesshttps://creativecommons.org/licenses/by-nc-nd/4.0/article10.5545/sv-jme.2008.0292-s2.0-79955802679