PSI - Issue 42

Martina Drdlová et al. / Procedia Structural Integrity 42 (2022) 1382–1390 Drdlova et al/ Structural Integrity Procedia 00 (2022) 000 – 000

1388

7

fragmentation, which was reduced to 0 by the additional layer of polyurea. Fig. 3 shows the example of failure mode of the PC PU and PC specimen.

Fig. 3 Example of failure mode of sample PC (left) and PC with polyurea coating (right)

3.3 Design and verification of the vehicle restrain barrier The restraint system to stop vehicles (N1 category - 3.5 t) was designed based on the findings of previous research. The PC material reinforced by ribbed steel and polyurea coating has been selected as optimal solution taking into account the shape parameters, total mass of the barrier and cost/performance ratio. The final shape of the block is the result of extensive numerical simulations aimed at optimizing the shape in terms of required behaviour after impact. Numerical simulations were performed in LS-DYNA software. The shape of the barrier is designed to partially convert the kinetic energy of the vehicle into potential energy upon impact. This is achieved by a controlled flipping of the block, when the lower protrusion is wedged under the front of the vehicle chassis, while lifting and immobilizing the vehicle. The friction of the upper protrusion, which comes into contact with the ground, then contributes to the deceleration of the movement. As the element is expected to be used in the urban area, emphasis was also placed on design, stability in use and the possibility of multifunctional use. The designed element can therefore serve as an element of urban furniture (e.g., a table). The verified element shapes and the final design are summarized in Fig. 4. En example of numerical simulation of the barrier behaviour during the vehicle impact depicts the Fig. 5.

Fig. 4 Summary of proposed barrier shapes verified by numerical simulations (left) and final shape of the barrier (right)

Fig. 5 Numerical simulation of the barrier behaviour during the vehicle impact

After determining the most suitable shape and dimension parameters and verification of the effectiveness of the barrier by numerical simulations, the system was subjected to real crash test according to CWA 16221:2010, see Fig. 6. The barrier was tested, in accordance with the standard, at a vehicle speed of 48 km/h. The barrier resisted the impact of a 3.5 t vehicle without any problems. Polyurea successfully suppressed all potential fragmentation. No critical locations on the barrier were identified. The barrier can be assessed as effective in terms of stopping the vehicle at an impact speed of 48 km/h; the penetration into the protected area is only 3.05 m.