PSI - Issue 47

Andre Hartawan Mettanadi et al. / Procedia Structural Integrity 47 (2023) 168–175 Mettanadi et al. / Structural Integrity Procedia 00 (2019) 000 – 000

170

3

=

(1) where M and EA represent the total mass and energy absorption of the cylinder, respectively. EA is equal to the area surrounded by the force-displacement curve as in the example : ∫ ( ) 0 . The cut-off transfer of the energy absorption process is determined according to the energy efficiency method can be seen from Equation 2. In addition the mean crushing force (MCF) is analyzed as the average energy absorptions experienced by the material can be seen from Equation 3 ( ) = ∫ ( ) 0 ( ) (2) = ( ) (3) where η ( d ) represents energy absorption efficiency. The cut-off displacement (point C) as can be seen from Figure 1b is the displacement value corresponding to the stationary point (point A) where the global efficiency is maximum. The SEA corresponding to point C is the total specific energy absorption. Meanwhile the MCF represents the mean crushing force value or the average crushing force from the curve shown in Figure 1a starting from the yield point until the material fractures. 3. Research Method 3.1. Structural configuration In this research, a concave hexagonal structure is constructed as a filler element in the cylindrical shell as shown in Fig. 3, which are distributed along with the circumferential and radial directions of the cylindrical shells, which are connected by circular arcs. We assume that the diameters of the inside diameter and the outside diameter are represented by d and D , respectively. The coefficient α is used to express the ratio between the two diameters, i.e. α = d / D . The number of concave hexagons in the perimeter and radial distributions are denoted by x and y , respectively. As shown in the Figure 2, the cylindrical shell has a uniform thickness distribution with t = 1 mm. The section parameters α , x and y are 0.5, 6 and 2, respectively. The cylindrical shell has an axial height of 150 mm and an outer ring diameter of 60 mm.

Figure 2. Geometrical models of the designed Cyl-1 specimen.