Modeling crowd pushing behavior for ship pedestrians evacuation based on improved social force model

The occurrence of crowd pushing significantly reduces evacuation efficiency and increases the risk of casualties. To quantify the impact of pushing behavior on the evacuation process, this paper develops a ship pedestrians evacuation model based on the Social Force Model. The improved social force model uses a Sigmoid function to describe how the panic coefficient influences the intensity of the pushing force. It also introduces the conditions of pedestrian spacing and movement direction to determine when pushing forces occur, allowing for dynamic evaluation of the pushing force during the evacuation process. The simulation results show that as the panic coefficient increases, evacuation time exhibits a nonlinear growth trend, with evacuation efficiency dropping sharply under high panic conditions; the greater the pushing force, the longer the evacuation time. A comparative analysis with typical tests from MSC.1/Circ.1533 guidelines and simulation results from the Pathfinder evacuation software shows that the model proposed in this study effectively simulates the pushing behavior between pedestrians in a panic state and can accurately assess the impact of panic on the evacuation process. The model can be used to evaluate the evacuation capacity of a ship’s pedestrians in panic situations.