en Optimal design Optimal design پژوهشي Research <span style="font-size:11.5pt"><span new="" roman="" style="font-family:" times="">Structural optimization plays a crucial role in engineering design, aiming to minimize weight and cost while satisfying performance constraints. This research presents a novel Self-Adaptive Enhanced Vibrating Particle System (SA-EVPS) algorithm that automatically adjusts algorithm parameters to improve optimization performance. The algorithm is applied to two challenging examples from the International Student Competition in Structural Optimization (ISCSO) benchmark suite: the 314-member truss structure (ISCSO_2018) and the 345-member truss structure (ISCSO_2021). Results demonstrate that SA-EVPS achieves significantly better solutions compared to previous studies using the Exponential Big Bang-Big Crunch (EBB-BC) algorithm. For ISCSO_2018, SA-EVPS achieved a minimum weight of 16543.57 kg compared to 17934.3 kg for the best EBB-BC variant&mdash;a 7.75% improvement. Similarly, for ISCSO_2021, SA-EVPS achieved 4292.71 kg versus 4399.0 kg for the best EBB-BC variant&mdash;a 2.42% improvement. The proposed algorithm also demonstrates superior convergence behavior and solution consistency, with coefficients of variation of 3.13% and 1.21% for the two benchmark problems, compared to 12.5% and 2.4% for the best EBB-BC variant. These results highlight the effectiveness of the SA-EVPS algorithm for solving complex structural optimization problems and demonstrate its potential for engineering applications.</span></span> Structural optimization, Metaheuristic algorithms, Self-adaptive parameters, Vibrating particle system, Truss structures, ISCSO benchmarks, Size optimization, Parameter tuning 111 130 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-6463-20&slc_lang=en&sid=1 M. Paknahd 180031947532846002818 180031947532846002818 No Faculty of Engineering, Mahallat Institute of Higher Education, Mahallat, Iran P. Hosseini p.hosseini@mahallat.ac.ir 180031947532846002819 180031947532846002819 Yes Faculty of Engineering, Mahallat Institute of Higher Education, Mahallat, Iran A. Kaveh 180031947532846002820 180031947532846002820 No School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran S.J.S. Hakim 180031947532846002821 180031947532846002821 No Department of Civil Engineering, Faculty of Civil Engineering and Built Environment, University Tun Hussein Onn Malaysia (UTHM), Malaysia