PSI - Issue 41

Ilham Widiyanto et al. / Procedia Structural Integrity 41 (2022) 274–281 Widiyanto et al. / Structural Integrity Procedia 00 (2022) 000 – 000

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1. Introduction In order to satisfy lightweight requirements and structural efficiency, large cylindrical structures are reinforced by stiffeners. Shell structures have a wide range of potential applications in the mechanical system, from macro to nanoscale (Yusvika et al., 2020; Liu et al., 2021; Prabowo et al., 2017-2021). Thin-walled steel cylindrical shells with end caps are used in various industrial sectors to store multiple fluids, such as water, petroleum, and petrochemicals. Large shell cylinders are made in layers to obtain the desired cylinder strength with economic considerations. The shell wall thickness increases progressively from top to bottom of the cylindrical shell (Fazlalipour et al., 2016). Cylinders with thick walls can also be applied to offshore pipes. The thickness of the cylinder shell and material must withstand axial and external pressures that cause buckling. The pressure shell structure, an essential aspect of deep diving submersible technology, has been studied extensively (Zhang et al., 2017). The cylindrical shell is the most commonly used deep-sea pressure shell structure (Iakovlev, 2019). There are two types of cylindrical shells, namely, cylindrical shells stiffened with a rib to ensure their stability and unstiffened cylindrical shells . Many researchers have investigated the critical buckling load under pressure. Zaczynska et al. (2020) conducted a study on parametric studies of the dynamic buckling phenomenon of a composite cylindrical shell under impulsive axial compression. Guha et al. (2020) conducted a test of the parametric solution for lateral buckling of subsea pipelines. This research examines the problem of buckling on non-straight on-bottom pipes subjected to axial compression loads. Research on Lateral Bending Theory and Experimental Study of Pipeline Structures in Pipes was carried out by Zhang et al. (2019). This study examined the structure of deep-sea oil pipelines to exploit marine oil and gas. Factors affecting lateral buckling of pipe-in-pipe (PIP) systems containing initial imperfections. Jiao et al. (2021), investigated thin-walled cylindrical shells under localized axial compression in 2 parts. The study compared the experiment results and used the Finite Element Method (FEM). Based on previous research, it is necessary to develop a model to strengthen the structure of the model on buckling behavior. One of them is by adding a stiffener to the outer shell of the cylinder shell. In this paper, analysis focuses on the critical load capacity of the cylindrical shell. A parameter study was conducted to investigate the effects of these parameters, including structural parameters such as geometrical and cylindrical diameter. The shell cylinder is varied by using two types of stiffener, namely stringer-stiffened and ring-stiffened, which are subjected to a combination of pressures. The pressure is in the form of uniform external pressure and axial compression. The three cylinders are designed with equal structural weight to make adjustments to other cylinder geometry parameters. After the geometric measurement, it is verified with different mesh sizes. The mesh size affects the critical load results. This analysis uses FEM with imperfections. This simulation is also run with the ABAQUS/CAE software with the RIKS Algorithm. 2. Benchmarking Analysis Experiments and theoretical analysis were carried out by Zhu et al. ( 2018) to investigate the buckling of unstiffened cylindrical shells under external pressure. The experiment used a six cylinders shell with 304 stainless steel material that has a thickness of 1 mm. At the top and bottom of the shell cylinder, shell caps are installed with a diameter of D = 120 mm and a thickness of t = 10 mm. The length of the cylinder used is l = 49.67 mm . The thickness is 10 times the thickness of the cylinder shell. The diameter, average lengths, and standard deviations of the specimens are listed in Table 1. The researcher assumes that all shell cylinders have an inner diameter of D = 100 mm with a thickness t = 1 mm. The strain was measured in the transverse and longitudinal directions to obtain the Poisson’s ratio ( v ). The ratio value used is 0.25.

Fig. 1 Measurement specimen dimension