PSI - Issue 83

Kemal Arslan et al. / Procedia Structural Integrity 83 (2026) 218–228

221

20 mm

35 mm

Wall thickness = 2 mm

6.67 mm

10 mm

Steel tube

MF1

MF2

MF1-M

MF2-M

m = 0.6354 kg

m = 1.2720 kg

m = 0.9422 kg

m = 0.6459 kg

m = 0.6360 kg

Fig. 3. The cross-sections of the steel tube and the original and modified MF structures.

3. Finite Element Modeling Dynamic axial crushing simulations of the MF tubular structures were performed using the explicit finite element code, LS-DYNA. The FE model, comprising a rigid striker and an MF tubular structure, is shown in Fig. 4. The FE parts were meshed using eight-node solid elements with an input element size of 1.5 mm, based on a mesh dependence analysis.

Fig. 4. The finite element model of the MF tubular structure for the crush simulations.

The elastoplastic behavior of the structures was modeled using the Johnson–Cook (JC) plasticity model [Johnson and Cook (1985)]. The well-known form of the JC model defines the flow stress by incorporating three main parts: strain hardening, strain-rate hardening, and thermal effects. Due to the relatively low velocity regime of this simulation, it allows simplifying the JC model as follows: ௬ ൌൣ ൅ ܤ ௣௡ ൧൤1൅ ݈݊ܥ ൬ ሶ ሶ ଴ ൰൨ (2) where A , B , n , and C respectively specify the yield strength, hardening modulus, hardening exponent, and strain-rate