PSI - Issue 52

Satrio Wicaksono et al. / Procedia Structural Integrity 52 (2024) 438–454 Satrio Wicaksono et al./ Structural Integrity Procedia 00 (2023) 000 – 000

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q : Mises equivalent stress ̇ : plastic strain The criteria for initiating failure are met if the following conditions are met: = ∫ ( , ̇ ) =1 where is the condition variable that increases monotonically with plastic deformation. At each increment during the analysis, the additional increment is calculated as: ∆ = ∆ ( , ̇ ) ≥0 2.2. Final Assembly

The final assembly of the finite element model of the sandwich T-joint structure is presented in Figure 3. As shown in Figure 4, the impact simulation allowed the impactor to hit the T-joint structure with a velocity of 4.76 m/s, which is equivalent to kinetic energy of 60 J. Meanwhile, the support block and clamps were totally constrained. In the meshing process, the whole structure of T-joint was constructed out of several different types of element. The selected type of element had to be compatible with material type definition. The enhanced hourglass control along with the second-order accuracy options were also activated to minimize the effect of element distortion. Then, to model core shearing, the element deletion option was activated. The element deletion option would delete the element experiencing failure or crack once maximum failure limit ( D ) was reached. The type of element utilized for the core and skin components of sandwich structure is the C3D8R, which is suitable for modelling the 3D component that is likely to experience large plastic deformation. The cohesive layers were assigned with the COH3D8 type of element. This type of element is often to model extremely thin components, and specifically defined for cohesive materials.

Figure 3 Final assembly of the finite element model of the sandwich T-joint structure.

Figure 4 Loading and boundary conditions at T-joint structure.