PSI - Issue 59

B. Ganendra et al. / Procedia Structural Integrity 59 (2024) 238–245 Ganendra et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Introduction The presence of modern-day technologies has driven the world into a higher level of readiness to explore the renewable energy sources (Prabowoputra et al., 2021; Adie et al., 2023a,b; El Yaakoubi et al., 2023; Lutfi et al., 2023; Naufal et al., 2023; Wijaya et al., 2023). The development of infrastructures plays an essential role to boost up the energy transition. Through the years, numerous infrastructures, such as energy production facilities and transportation, have relied on cylindrical shell structures to build the entire structure. Cylindrical shell is a structural element that is widely used in numerous engineering applications such as in onshore, offshore, aircraft, and even in deep-sea submersible vehicle structures (Do et al., 2022; Prabowo et al., 2022). For instance, cylindrical shell structures can be found in the form of submarine pipelines used to transport natural oil and gas from offshore oil rigs to an onshore refinery facility (Showkati and Shahandeh, 2010; Do et al., 2023; Suryanto et al., 2023). In another practical field, cylindrical shell structure is commonly used in wind turbine tower support structures in the form of steel circular hollow sections (CHS) (Adiputra et al., 2023; Ganendra et al., 2023) . As the world’s demand on renewable energy rapidly growing in the last two decades, wind turbine is a great solution to satisfy the need for green energy. To ensure that there is always sufficient electrical energy produced by wind energy modern-day wind turbines were built with larger size compared to the older ones as this is a solution to achieve higher power generation efficiency and capacity (El Yaakoubi et al., 2023; Gupta et al., 2021; Kang et al., 2021). Besides make it possible to create wind turbine in larger sizes (longer blades, taller towers, and higher rated power) modern-day technologies also been developed to make the wind turbine systems more sustainable against mechanical and environmental loads as larger wind turbine systems are susceptible to higher fatigue damage due to higher unsteady aerodynamic loads (Gupta et al., 2021; Serrano- González and Lacal- Arántegui, 2016). Forensic studies conducted from 2007 to 2017 revealed that among the four types of the most common failure occurred in wind turbine systems, the most critical issue of wind turbine systems is either the tower or the foundation failure (Chen et al., 2022). Generally, the failure of a wind turbine tower is caused by lateral wind gushing towards the tower, causing a bending moment on the tower structure (Guo et al., 2013; Li et al., 2023; Chen et al., 2024; Zhang et al., 2024). 2. Literature Review Cylindrical shell structure under bending moment load has been studied by numerous researchers in previous studies. Experimental tests on cylindrical shell structure were carried out by Chou et al. (2021) and Guo et al. (2013). In the research conducted by Chou et al. (2021) steel cylindrical structures were tested using two types of loadings, i.e., increasingly monotonic loading and cyclic loading. The data obtained from the experiment was later compared with the analytical result obtained from formula provided by AISC 360 (AISC, 2022) and EN1993-1-6 (European Standard, 2007) with the formula given as follows:  US Standard / AISC 360 It should be noted that a certain limitation that must be obeyed within this standard is that the structural member is classified into three groups according to the cross section as a compact, non-compact or slender, and the formula is diverse for each class. The formula to be used to calculate the nominal flexural strength ( ) of the cylindrical structure are described in Eqs. 1 to 3. ; (1) ( ) ; (2)