## 2 Side Pole Impact Simulation Analysis
### Side Pole Impact Analysis of the Original Vehicle Model  
According to European side pole impact test regulations, the test involves a vehicle impacting a stationary rigid pole at a speed of 32 km/h. The pole, with a diameter of 254 mm, was positioned such that its central axis aligned with the center of gravity of the driver's head. During the side pole impact test configuration, a 75\({}^{\circ}\) angle was maintained between the vehicle's longitudinal centerline and the prescribed impact direction vector, as shown in Figure 4. Based on these regulations, a finite element model for the side pole impact was established. The contact between the rigid pole and the full-vehicle finite element model  
Figure 3: Deformation of the whole vehicle frontal side at the end of the full frontal collision test and simulation test: (**a**) real-vehicle test; (**b**) simulation test.  
Figure 2: Comparison of acceleration results at the lower measuring point of the B-pillar in full-width frontal collision tests and simulation tests.  
was defined as automatic surface-to-surface contact, with a friction coefficient of 0.3 to accurately simulate component interactions during collision. The material failure criterion was strain-based, as illustrated in Figure 5, and a series of simulation tests were conducted.  
Traditional side pole impact tests for vehicles primarily focus on B-pillar intrusion. However, for electric vehicles, the battery pack mounted at the vehicle's bottom is equally critical. This study specifically examines both lower sill intrusion and battery pack deformation. As shown in Figure 6, the side pole impact simulation of the original vehicle indicates that the deformation is concentrated within the narrow space around the B-pillar. The small collision contact area and resulting impact force cause significant intrusion on the vehicle's right side, resulting in a V-shaped deformation of the body, B-pillar twisting, and severe deformation of the lower sill beam.  
Based on ES-2 side impact dummy data, three observation points were established near the B-pillar (Figure 7), corresponding to the head, chest, and abdomen regions, with an additional point on the lower sill beam. Analysis of the measurement data (Figure 8)  
Figure 4: E-NCAP side pole impact test schematic.  
Figure 5: Finite element model of side pole impact testing.  
Figure 6: The lower vehicle body deformation of the original model in the side pole impact simulation.  
reveals that the intrusion values at principal monitoring locations exceeded the maximum permissible threshold of 350 mm. Notably, the peak intrusion recorded in the chest region reached a critical level of 396 mm, posing a significant threat to occupant safety.  
By observing the deformation of the battery pack at the bottom of the vehicle in Figure 9, it was found that the original design results in significant deformation of the bottom. This is primarily due to the side impact on the vehicle, which causes severe compression of the right longitudinal beam of the battery pack, leading to significant deformation of both the battery pack bracket and the battery pack itself. The measurement results show that the maximum intrusion of the battery pack's sidewall reaches 107.7 mm, approximately 16.3% of the overall dimension. The degree of deformation presents a clear safety hazard [25].