Minimization of weight in truss structures under probabilistic constrains

Document Type : Civil Article

Author

Assistant Professor, Department of Civil Engineering, Mahdishahr Branch, Islamic Azad University, Mahdishahr, Iran

Abstract

The main purpose of the reliability theory of structural systems is the optimal design based on the reliability concept. Trusses and space structures are widely used, and cost and safety both are important in these structures. Therefore the weight optimization of these structures based on the theory of reliability (probabilistic optimization) using Genetic Algorithms was studied in this paper. The objective function was weight of structure and the constraints were based on the failure probability of elements or nodes or the system. To increase the accuracy of structural safety calculations, the probabilistic form of buckling is presented in this research.
The results of this study show that increasing the system allowable failure probability decreases the optimum weight of structure. The process of this weight loss occurred at first with a very fast slope and then with a gentle slope and finally tended to a constant value. Optimum weight was very sensitive to coefficient of variation comparison of allowable failure probability. In the probabilistic optimization, if the system allowable failure probability and coefficient of variation of load and yield stress are considered near zero, and if results are compared to the deterministic optimization, the difference in optimum weight is less than 9%. In this case, convergence for deterministic optimization was very fast and occurred in less than 20 generations but convergence in probabilistic optimization occurred slowly after 85 generations.

Keywords


[1] A. S. Nowak, and K. R. Collins, “Reliability of structures”, Taylor and Francis Group, 2nd Edition, 2012.
[2] M. R. Ghasemi, and M. Yousefi, “Reliability-based optimization of steel frame structures using modified genetic algorithms”, Asian journal of civil engineering (Building and housing), Vol. 12, No.4, 2011, pp.449-475.
[3] V. Ho-Huu, T. Nguyen-Thoi, L. Le-Anh, and T. Nguyen-Trang, “An effective reliability-based improved constrained differential evolution for reliability- based design optimization of truss structures”, Advances in Engineering Software, Vol. 92, 2016, pp. 48-56.
[4] V. Ho-Huu, D. Duong-Gia, T. Vo-Duy, T. Le-Duc, and T. Nguyen-Thoi, “An efficient combination of multi-objective evolutionary optimization and reliability analysis for reliability-based design optimization of truss structures”, Expert Systems With Applications, Vol. 102, 2018, pp. 262-272.
[5] بهروز کشته گر و محمود میری، "ارائه روشی جدید برای ارزیابی قابلیت اعتماد سازه ها "، نشریه مدلسازی در مهندسی، دوره 12، شماره 36 ،بهار 1393، صفحه 29-42.
[6] H. Karadeniz, V. Toǧan, and T. Vrouwenvelder, “An integrated reliability-based design optimization of offshore towers”, Reliability Engineering and System Safety, Vol. 94, 2009, pp. 1510-1516.
[7] M. Zaeimi, and A. Ghoddosain, “System reliability based design optimization of truss structures with interval variables”, Periodica Polytechnica Civil Engineering, Vol. 64, No. 1, 2020, pp. 42-59.
[8] Z. Meng, H. Zhou, H. Hu, and B. Keshtegar, “Enhanced sequential approximate programming using second order reliability method for accurate and efficient structural reliability-based design optimization”, Applied Mathematical Modelling, Vol. 62, 2018, pp. 562-579.
[9] Y. Aoues, and A. Chateauneuf, “Reliability-based optimization of structural systems by adaptive target safety - Application to RC frames”, Structural Safety, Vol. 30, 2008, pp. 144-161.
[10] علی قدوسیان، امین نیکوبین و مجتبی ریاحی وزواری، "بهینه­سازی اندازه و شکل سازه­های خرپا با روش بهینه­سازی الگوریتم مثلث بهینه­گر"، نشریه مدلسازی در مهندسی، دوره 14، شماره 46، پاییز 1395، صفحه 51-60.
[11] سید روح الله موسوی، محمد رضا قاسمی و سعید فراهی شهری، "بهینه­سازی گسسته سازه­های خرپایی توسط روش مبتنی بر حساسیت سنجی، تقسیم­بندی و تجدید حیات"، نشریه مدلسازی در مهندسی، دوره 17، شماره 57، تابستان 1398، صفحه 127-146.
[12] V. Toǧan, and A. Daloglu, “Reliability and reliability-based design optimization”, Turkish Journal of Engineering and Environmental Sciences, Vol. 30, 2006, pp. 237-249.
[13] M. Shayanfar, R. Abbasnia, and A. Khodam, “Development of a GA-based method for reliability-based optimization of structures with discrete and continuous design variables using OpenSees and Tcl”, Finite Elements in Analysis and Design, Vol. 90, 2014, pp. 61-73.
[14] K. B. Hamedani, and V. R. Kalatjari, “Structural system reliability-based optimization of truss structures using genetic algorithm”, International journal of optimization in civil engineering, Vol. 8, No. 4, 2018, pp. 565-586.
]15[ علی حدیدی و سیمین چیت ساز، " طراحی بهینه سازه­های فضاکار مبتنی بر نظریه قابلیت اطمینان با استفاده از الگوریتم ژنتیک"، نشریه مهندسی عمران و محیط زیست، جلد 48، شماره 1، بهار 1397، صفحه 13-22.
[16] A. C. C. Lemonge, J. P. G. Carvalho, P. H. Hallak, and D. E. C. Vargas, “Multi-objective truss structural optimization considering natural frequencies of vibration and global stability”, Expert Systems With Applications, Vol. 165, 2021.
[17] ANSI/AISC 360-16, “Specification for Structural Steel Buildings”, American Institute of Steel Construction, Chicago, IL, 16th Edition, 2019.
[18] Aluminum Association, Aluminum Design Manual, Washington D.C, 2020.
]19[ علی کاوه و وحیدرضا کلات جاری، "نظریه قابلیت اعتماد و کاربرد آن در مهندسی سازه"، 1373، دانشگاه علم وصنعت ایران.
[20] C. A. Cornell, "Bounds on the reliability of structural systems", Journal of Structural Division, ASCE, Vol. 93, No. 1, 1967, pp 171-200.
[21] S. N. Sivanandan, and S. N. Deepa, “Introduction to genetic algorithms”, Springer-Verlag Berlin Heidelberg, 2008.
[22] L. Sahoo, A.  K. Bhunia, and P.K. Kapur, “Genetic algorithm based multi-objective reliability optimization in interval environment”, Computers and Industrial Engineering, Vol. 62, 2012, pp 152-160.
]23[ محمدرضا قاسمی و محمدرضا مستخدمین حسینی، "بهینه­سازی سازه­های فضاکار با درنظرگرفتن احتمال خرابی اعضاء و گره­ها به کمک الگوریتم وراثتی اصلاح شده"، نشریه دانشکده فنی، دوره 42، شماره 4، مرداد 1387، صفحه 477-485.