PSI - Issue 27

Laksmana Widi Prasetya et al. / Procedia Structural Integrity 27 (2020) 132–139 Prasetya et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Table 1. Mechanical properties of waste food cans. Material type

Properties

Values

Density (kg/mm 3 )

27126 x 10 -3

Modulus of Elasticity (GPa)

689480 689480

Alumunium alloy 3004

Yield Stress (GPa) Poisson’s Ratio

0.33

The following Table 2 below is the mechanical properties used for rigid parts, the first rigid wall as a collector, rigid plate, and the last is anti-intrusion plate as support.

Table 2. Mechanical properties of rigid parts. Material type

Properties

Values

Density (kg/mm 3 )

0.75 193 0.33

Rigid material

Modulus of Elasticity (GPa)

Poisson’s Ratio

2.2. Impact scenario In this study, the impact of attenuators with waste cans is processed with the ANSYS LS-DYNA application, which is proven powerful enough to analyze impact phenomena (Prabowo et al., 2019; 2020). The meshing elements on the used cans are entirely modeled with a 5 mm meshing size using a rectangular element type. Then for all parts formed by the kind of shell element by determining the thickness of each component. This type of shell element has the advantage of being faster in running it to get simulation results. They are then setting the boundary conditions, for rigid walls to be fully restricted to all degrees of freedom, except to translate in the direction of the z-axis as far as -200 mm. For plates separating the top and bottom cans, all degrees of freedom are given except for translation on the z-axis. At the same time, the end of the anti-intrusion plates is applied by all restrictions, including translational and rotational displacement. The anti-intrusion plate here must not be able to move because it functions as a support. Waste cans in this impact attenuator are used for this type of material, namely piecewise linear plasticity, and for rigid parts, all of them are defined using rigid materials. It is hoped that this rigid material will not be deformed so that the can will be distorted, and the load will be forwarded to the bottom can. In this situation, the anti-intrusion will survive at the very bottom location. In this simulation, two types of defined contacts are used. The first is an automatic knot to the surface, which is used for contact between cans and rigid parts. Next, the second is a single-automatic surface for the contact between the surfaces of the can itself when the can is deformed. According to body interactions, contact between the plates and the attenuator works as a friction phenomenon, in which the static and dynamic friction coefficients 0.4 and 0.3 are applied, respectively. The output of the numerical simulation is the deformation behavior, which is engineering stress, strain, von-Mises stress, and displacement. It is important to know each system and to use the system most appropriate to a given technical situation. The expression in Eq. 1 defines engineering stress. = / 0 (1) where A 0 is the original cross-sectional area of the gage section. The expression in Eq. 2 gives engineering strain. = ( − 0 )/ 0 (2) The von-Mises criterion involves all three principal stresses and can be written as presented in Eq. 3. 0 = 2 −1/2 [( − ) 2 + ( − ) 2 + ( − ) 2 ] 2 (3) When the value of the right side of Eq. 2 reaches the value of the flow stress, ε o , then yielding and plastic flow will occur. The von-Mises criterion is equivalent to saying that yielding will occur at a critical value of the elastic energy in the material.