PSI - Issue 47

M. Iqbal Maulana et al. / Procedia Structural Integrity 47 (2023) 150–158 Maulana et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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As can be seen in Figure 7, the maximum of the values for the plastic-hoop strain are 0.09303 and 0.1505. The lowest values are -5.146e-06 and -7.493e-05. The maximum results are mostly occurred on the inside of the pipe profile frame because on this area the pipe was directly exposed to the explosive effects of TNT. Meanwhile, the minimum plastic-hoop strain occurs at the upper end of the pipe structure. This was possible because this area was not affected by the explosion from the TNT that occurred right in the middle of the pipe. Based on the data obtained, it can be concluded that the value of the strain is directly proportional to the addition of TNT load. The greater the TNT loading, the greater the strain value. 5.2 Displacement behaviour Deflection is a major consideration in the design of structures [Ji, 2020]. The control of the structural deflection will be higher if the building becomes taller, the bridges longer, and the more complicated the shape of the building to be built. To evaluate the design, there are many methods that can be done. It should be noted that at the initial state, all displacements are initially 0 [Dzulfiqar et al., 2021]. Following are the results of finite element displacement analysis for the pipe structure affected by the explosion (0.6 kg TNT loading and 0.8 kg TNT with 0.0025 m meshing) shown in Figures 8 and 9.

Figure 8. Displacement Result from TNT 0.6 kg Meshing 0.0025 m.

Figure 9. Displacement Result from TNT 0.8 kg Meshing 0.0025 m.

The maximum values for displacement of the structure with an explosive loading of 0.6 kg and 0.8 kg are 0.01479 m and 0.02478 m. The highest results mostly occurred on the inside of the pipe profile, where the location was directly affected by the TNT explosion, which was right in the middle of the pipe. The lowest value of both structure displacements is 0. The displacement value is 0 because the end of the pipe is not affected by the TNT explosion. 5.3 Meshing configuration Mesh is a facility for dividing and determining the type of element, type of part, or assembly. The smaller the meshing used, the more elements and the results obtained will be more detailed and precise. The calculation process on the computer will take some time longer. If a large meshing is used, the time used will be shorter, but the calculation results on the computer are not precise and detailed. Therefore, convergence calculations are carried out in the analysis finite element method for element size selection. When used, the size of these elements can be effective in terms of the calculation process time and the resulting value remains accurate. Here is the result of the plastic-hoop strain convergence mesh for the pipe structure after the explosion, and is shown in Figures 10 and 11. The results of the displacement mesh convergence for the pipe structure after the explosion are shown in Figures 12 and 13. From the convergence mesh data, we can conclude which meshing is the most stable so that it can be used for testing.