en Optimal design Optimal design پژوهشي Research <span style="font-size:11.5pt"><span new="" roman="" style="font-family:" times="">Design optimization of structures with discrete and continuous search spaces is a complex optimization problem with lots of local optima. Metaheuristic optimization algorithms, due to not requiring gradient information of the objective function, are efficient tools for solving these problems at a reasonable computational time. In this paper, the Doppler Effect-Mean Euclidian Distance Threshold (DE-MEDT) metaheuristic algorithm is applied to solve the discrete and continuous optimization problems of the truss structures subject to multiple loading conditions and design constraints. DE-MEDT algorithm is a recently proposed metaheuristic developed based on a physical phenomenon called Doppler Effect (DE) with some idealized rules and a mechanism called Mean Euclidian Distance Threshold (MEDT). The efficiency of the DE-MEDT algorithm is evaluated by optimizing five large-scale truss structures with continuous and discrete variables. Comparing the results found by the DE-MEDT algorithm with those of other existing metaheuristics reveals that the DE-MEDT optimizer is a suitable optimization technique for discrete and continuous design optimization of large-scale truss structures.</span></span><br> &nbsp; metaheuristics, Doppler effect, mean Euclidian distance threshold mechanism, discrete optimization, continuous optimization, truss structures. 335 364 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-66-345&slc_lang=en&sid=1 A. Kaveh Alikaveh@iust.ac.ir 180031947532846002687 180031947532846002687 Yes School of Civil Engineering, Iran University of Science and Technology, P.O. Box 16846- 13114, Iran S. M. Hosseini 180031947532846002688 180031947532846002688 No School of Civil Engineering, Iran University of Science and Technology, P.O. Box 16846- 13114, Iran