## 4 Discussion  
The node-sharing model has a slight advantage in terms of computation time compared to the node-independent model, as it does not require additional constraint equations related to the interaction between concrete and reinforcement. However, for the node-sharing model, as the complexity of the system's geometry to be analyzed increases, the time required for the preprocessing phase can significantly increase. Additionally, using the node-sharing model can lead to poor aspect ratios of solid elements, which negatively affect the accuracy and reliability of numerical analysis results. In other words, as the nonlinearity and complexity of the geometry represented in the system increase, the complexity of modeling and the magnitude of increase in analysis time can also become greater. Therefore, while the computation time for the node-independent model may slightly increase, using the node-independent model for the impact analysis of reinforced concrete barriers can avoid the major issues associated with the node-sharing model. The node-independent model adopted in this study provides a simplified modeling approach for actual reinforced concrete barriers. Next, the strength performance of the reinforced concrete barrier was evaluated by comparing scenarios with and without the bridge deck. Due to the differing material properties of reinforced concrete structures, distinct criteria are needed to assess stresses in the steel reinforcement and the concrete. For steel reinforcement, von Mises stress is applied to predict yielding under multiaxial stress conditions in ductile materials. This approach provides a scalar value indicating potential yielding under complex loading conditions. Excluding the bridge deck, the stress reached 382 MPa, and with the deck, it reached 399 MPa, approaching the yield stress of 400 MPa. Consequently, some reinforcement may yield as a result of the collision. Notably, the yielding location varied: without the bridge deck, yielding occurred in the sloped section at the barrier's lower part, whereas with the deck, significant stress was observed at the connection between the barrier and the deck. Additionally, considering the bridge deck resulted in significant stress at the connection and larger stresses over an extended area along the barrier's length. Concrete, being inherently brittle, shows reduced strength under axial stress. Therefore, the maximum principal stress was evaluated against the compressive strength of 35 MPa to verify any exceedance. In both scenarios, the maximum principal stress was approximately 2 MPa, indicating no significant difference in concrete strength evaluation between the models. Passenger impact severity was evaluated using a passenger car as the impact vehicle, with THIV and PHD serving as indicators. THIV is calculated as the instantaneous relative velocity between the vehicle and the passenger's head during the collision with the barrier, causing the head to impact an imaginary surface freely within the vehicle's interior. This indicator assesses the impact energy received during the collision, predicts the severity  
Figure 14: Post-impact trajectory of passenger cars: (**a**) Case 1; (**b**) Case 2; (**c**) Case 3. Figure 13: Post-impact trajectory of trucks: (**a**) Case 1; (**b**) Case 2; (**c**) Case 3.  
of head injuries, and indicates potential passenger injury levels. PHD is based on the assumption that after the passenger's head impacts an imaginary surface within the vehicle's interior, it directly experiences the vehicle's deceleration. It is calculated as the maximum average deceleration over 10 milliseconds. This indicator plays a crucial role in assessing head and neck injury risks and verifying the effectiveness of vehicle safety devices. In the Republic of Korea, the allowable standard for THIV is 33 km/h or less, and for PHD, it is 20 g or less [26].