PSI - Issue 72

Gusti Kid Faiq Syah et al. / Procedia Structural Integrity 72 (2025) 401–408

402

As of 2016, more than 49,000 merchant ships with almost 1.8 billion deadweight tons were operating, where, of these, oil tankers, bulk carriers, and container ships took up 28%, 43%, and 13%, respectively (Tam, 2022). Maritime oil theft has become a critical issue worldwide due to its impact on global energy security and marine transportation systems. Researchers have conducted thorough studies on this issue, concentrating on oil-rich regions such as the Gulf of Guinea, Malacca Strait, and the Horn of Africa (Alexopoulos, 2023).

3%

7%

120000

4%

100000

32%

11%

Grounding Allision/collision Hull failure Fire/explosion Equipment failure Other Unknown

80000

60000

40000

Oil Leaks (Tons)

13%

20000

0

30%

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

Year

(a) (b) Figure 1. Statistical data of marine incidents: (a) Cause of global oil tanker since 1970-2023, and (b) Cause of global oil tanker spills (ICC IMB., 2023; ITOPF., 2024a,b). Figure 1 presents that allision or collision is the cause of most accidents that happen. Oil and other hazardous materials in the event of an accident will result in fatalities and loss of property, along with environmental pollution (Khan et al., 2021). In addition to these environmental issues, damage to goods, properties, port infrastructure, and portfolio are also of critical concern. Such accidents could incur substantial financial losses (Khan et al., 2021). The cargo containment system should be designed to withstand impacts from dropped objects, which is crucial for the structural safety of Liquified Natural Gas (LNG) cargo containment systems (Nubli et al., 2022a,b; Suryanto et al., 2023; Jeon et al., 2023). Depending on the specific type of hazardous item, the impact of extreme heat, physical shock, high frequencies, electric energy, or electromagnetic radiation may cause the hazardous item to detonate ( Soğancılar, 2021). In this cautious examination, the parameters considered most are energy absorption and residual velocity of projectiles. Using a numerical approach, this investigatesthe factors that affect the energy absorption of targets and velocity reduction on projectiles where the bunker's safety depends on the bunker's protection wall. The impact requires a high-speed projectile to hit the target due to the deformation of the target plate. 2. Numerical model and simulation This section explains the finite element model in the scope of ballistic impact simulation in LS-DYNA (Prabowo et al., 2017; Zarei et al., 2017). The simulation setup will be reviewed comprehensively. In this study, the material properties are referred to in the study conducted by Alwan et al. (2022), which describes aluminum. Ballistic impact boundary conditions and geometry will be used in the finite element configuration to analyze residual velocity and absorbed energy after impact. Within the comprehensive scope of this research, the selected model capacities represent the bunker wall section of an oil tanker ship. The model intricately captures the complexities of a flat panel structure skillfully represented within the mounted circular plate with a standard thickness of 1 mm, as depicted visually in Figure 2. A three-dimensional finite element model of a 1 mm thick circular plate with an outer diameter of 315 and 9 holes distributed across the edges of the circle plate with a 15 mm diameter was created in LS-DYNA/CAE to study the effect of residual velocity and energy absorption. An ogive head cylindrical projectile with a diameter of 19 mm, a length of 50.8 mm, and a mass of 60 g was used to study the dynamic response of the plate.