PSI - Issue 5

Jung Min Sohn et al. / Procedia Structural Integrity 5 (2017) 935–942 Aditya Rio Prabowo et al. / Structural Integrity Procedia 00 (2017) 000 – 000

937

3

the influencing factors. This characteristic attracts researchers from wide ranges of science and engineering to analyze and study this phenomenon. In terms of classification of parameters, Zhang (1999) presented in his work that the parameters are divided into the external dynamics and internal mechanics of ship collision. Ship mass (type), velocity, collision location and angle are the main parameters for the external dynamics which later can be verified by the structural response in the internal mechanics. There are several calculation methods to estimate this response (Prabowo et al., 2017a-c), such as empirical methods as introduced by Minorsky (1958), Vaughan (1978), Woisin (1979) and Paik (1994). The formulae of these works are presented in Eqs. 1 to 4. Other methods are also considered good enough to be applied for collision observation, for instance analytical method in Eq. 5 (Pedersen, 1998) and the upper-bound theorem approach (Kierkegaard, 1993 and Paik and Pedersen, 1995), experimental study (Kulzep et al., 1999 and Peschmann et al., 1999), and finite element method (Bae et al., 2016a, Prabowo et al., 2016a-b and Prabowo et al., 2017d) which will be discussed furthermore in the next sub-section. E = 47.2 R T + 32.7 (Minorsky, 1958) (1) E = 93 R T + 33 A (Vaughan, 1978) (2) E = 47.2 R T + 0.5 Σ ( h . t s 2 ) (Woisin, 1979) (3) E = C 1.5 σ 0 l 1.5 t e q 1.5 (Paik, 1994) (4) side = 263 β [1.0 + 0.88( b / D ) 1.06 ] . [ L /300] 2.20 (Pedersen, 1998) (5) Fundamental of the ship collision is also the definition of contact between two rigid entities. This concept is introduced by Stronge (2004) that later is adopted for structure-ice interaction by Liu and Amdahl (2010) to propose a new formulation of the impact mechanics of ship collisions and Bae et al. (2016b) in their calculation of the damage calculation of a chemical tanker under collision with level ice. In collision, casualties during penetration of the striking ship into the target ship is unavoidable. Structural failure will take place, especially on the struck ship. Failure criteria are applied on the deformable structure in order to obtain satisfactory deformation contours and other structural behaviors. The German classification society proposed a recommendation to determine the failure strain (Germanischer Lloyd, 2003). A pioneer works from Peschmann and Lehmann (2002) also introduced correlation formulae between failure and meshing based on an experimental study. These formulae are presented in Eqs. 6 and 7 consecutively. ε f ( l e )= ε g + ε e . t s l e ⁄ (Germanischer Lloyd, 2003) (6) ε f ( l e )= ε g + α . t s l e ⁄ (Peschmann and Lehmann, 2002) (7) Recommendations of the failure criteria are encouraged to be used to achieve reliable results in reasonable time process. This process is needed to be conducted to preserve processing time during research. As described by Bathe (1996) it is impossible to reproduce physical phenomena even using the most refined mathematical model. Implementation of these failure models are embedded in several pioneer works, including Ehlers (2008), Haris and Amdahl (2013), and Prabowo et al. (2017e). 2.2. Calculation of a structural failure

3. Preparation and methodology

Analyses will be conducted by numerical analysis using explicit finite element (FE) codes ANSYS LS-DYNA (ANSYS, 2013). Material is defined together with the involved ship to conduct the analyses. A series of collision scenarios are defined in later sub-section to provide clear conditions of the modelled phenomena.