Ocean Engineering 190 (2019) 106443 Available online 24 September 2019 0029-8018/© 2019 Elsevier Ltd. All rights reserved. Design optimization of composite submerged cylindrical pressure hull using genetic algorithm and fnite element analysis Muhammad Imran a , Dongyan Shi a, * , Lili Tong b , Hafz Muhammad Waqas a a College of Mechanical and Electrical Engineering Harbin Engineering University, Harbin, 150001, China b College of Aerospace and Civil Engineering Harbin Engineering University, Harbin, 150001, China A R T I C L E INFO Keywords: Genetic algorithm Design optimization Submerged pressure hull Composite failure criteria Buckling strength factor Buoyancy factor ABSTRACT The design of structures made of laminated composites greatly depends on the fber orientation angle and the number of ply layers. In the present study design optimization of composite submerged pressure hull under 3 MPa hydrostatic pressure, which corresponds to 300 m depth, is carried out. The number of layers and orientation angles are optimized for layups [0 m /90 n /0 o ], [10 m /-10 n /90 o /-10 p /10 q ], [α 1m /α 2n ], [α 1m /α 2n /α 3o ] and [α 1m /α 2n /α 3o /α 4p /α 5q ] using three unidirectional composite materials, Carbon/Epoxy, Glass/Epoxy, and Boron/Epoxy. The optimization process is carried out in ANSYS Workbench using a Genetic Algorithm. Mini- mizing the buoyancy factor is used as the objective function of the optimization. The constraints on the opti- mization process are Tsai-Wu and Tsai-Hill failure criteria and buckling strength factor. Optimization study is also conducted for one selected layup confguration using ABAQUS and ISIGHT. Additionally, a sensitivity analysis is also carried out to study the effect of various design parameters on the optimum design of composite submerged pressure hull. 1. Introduction Fiber reinforced plastics (FRP) are advanced composites containing fbers such as carbon, glass, graphite and aramid as reinforcement ma- terial embedded in resin matrix such as epoxy. These composites are increasingly fnding their use in various applications such as aerospace, naval and other defense, automotive, sports and other industries. The outstanding properties of these composites as compared to metals are high specifc rigidity, high modulus of elasticity, good fatigue charac- teristics, lightweight, good corrosion resistance, less magnetic and acoustic signature (Gao and Cho, 2015). In the case of military aircraft F-15 and AV-08, the weight reduction over metal parts is more than 20%. In the automotive industry, FRP composites material are used in making various parts such as leaf spring, bumpers, panel bodies and doors (Kaw, 2005). The use of FRP composites in the construction of high-speed boats, mine countermeasure vessels and in various subparts of large naval vessels is well known. FRP composite materials are also used in the construction of submerged pressure hulls due to their high strength to weight ratio as compared to other metals and alloys. Therefore, composite pressure hulls will have greater collapse depth for a given weight to displacement ratio or reduced hull weight for a given operating depth as compared to other hulls made of steel and other al- loys (Challis et al., 2001). Fiber reinforced composite structures are fabricated from composite laminates using different layup confgura- tions and manufacturing techniques. There may be a number of layup confgurations, ply orientations and material systems which may result in the optimized design of composites structures. Studies related to the optimization of composite plates using a genetic algorithm (GA) coupled with numerical analysis are available in the literature. These studies have used composite failure criteria such as Tsai-Wu, Hashin, Maximum Stress and Puck failure criteria as material constraints and minimization of weight, minimization of defection, maximization of buckling load, minimization of material, and maximization of load carrying capacity as objective functions (Walker and Smith, 2003; Pelletier and Vel, 2006; Akbulut and Sonmez, 2008; Almeida and Awruch, 2009; Lopez et al., 2009; Topal and Uzman, 2010; Irisarri et al., 2011; Naik et al., 2011; Randrup, 2015). There have been many studies focusing on the design optimization of composite pressure hulls under external pressure using a GA and other optimization tools coupled with numerical analysis. The optimization studies have been conducted for different objective func- tions under constraints on buckling strength or both buckling and failure strengths. A comprehensive review about optimization of various * Corresponding author. College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin, No.145, Nontang Street, Nangang District, Heilongjiang Province, 150001, China., E-mail addresses: shidongyan@hrbeu.edu.cn, mehrarh@yahoo.com (D. Shi). Contents lists available at ScienceDirect Ocean Engineering journal homepage: www.elsevier.com/locate/oceaneng https://doi.org/10.1016/j.oceaneng.2019.106443 Received 30 January 2019; Received in revised form 8 July 2019; Accepted 15 September 2019