PSI - Issue 77

Christian J. Silva et al. / Procedia Structural Integrity 77 (2026) 631–638 Silva et al./ Structural Integrity Procedia 00 (2026) 000–000

634

4

υ

0.3 421.67 709.66 0.1095 0.294 609.03

0.3

0.3

σ y , [MPa] ε pmax σ max , [MPa] b n

946.667 450 1734.8 1629 0.171 0.4009 0.236 0.454 1368.22 1250.29

Poisson’s Ratio

Yield Stress

Hardening modulus Hardening exponent Plastic Strain at failure

Maximum stress

2.2. Collision Scenario A head-on collision was simulated between the railway vehicle modelled and a stationary rigid wall (Figure 2.a). This scenario is a simplified representation of the train-train head-on collision defined in scenario 1 of regulation EN 15227, widely used as a benchmark test to assess structural crashworthiness without the complexity of two deformable vehicles. An initial velocity of 18 km/h was imposed on the vehicle, which is half of the collision speed of scenario 1. A rigid floor was also modelled to simulate the interaction between the structure and the bogie at the interface nodes. Buffers are simplified as spring elements, characterised by the force-displacement curve of Figure 2.b. In terms of contact modelling, sliding with friction, restricted to the relevant regions, was imposed on the rigid bodies. Also, self contact between components was simulated using General Purpose Contact (Type 7) available in Altair Radioss (Altair Engineering, 2025).

a)

b)

Fig. 2. a) Collision scenario modelled and b) Force-displacement curve of the buffers

3. Results and Discussion Crash simulations were carried out using the explicit dynamic solver in Altair Radioss. To ensure computational efficiency while maintaining accuracy, an explicit time integration scheme was employed with a stable time step controlled through mass scaling, resulting in a minimum time step of 7.5 × 10 −7 [s] . These settings allowed the model to reproduce the highly dynamic response of the coach while keeping mass and energy errors below 5%, and a simulation run time of approximately 67 hours, which is within practical limits considering the scale of the model. 3.1. Crash behaviour of the baseline structure The vehicle dynamics obtained after head-on collision simulation of the baseline structure are depicted in Figure 4 for three simulation instants. It was possible to identify critical failure regions, especially the transition between the end chassis and the floor, with components collapsing mainly by buckling. The deformation around doors and