Abstract: Taking the air-supported membrane structure as the research object， using the fire dynamics simulator(FDS)， and considering the air leakage in the subgrid， the influencing factors of the internal pressure of the air-supported membrane structure without fire and the simulation method of the internal pressure under fire were studied. The results showed that the influence of air supply volume and leakage area should be considered in the internal pressure simulation of the air-supported membrane structure， and the larger the air supply volume， the smaller the leakage area， and the larger the corresponding stability value of the internal pressure. Based on the theoretical derivation and numerical simulation results， the internal pressure prediction formula of the air-supported membrane structure considering the influence of air supply volume and leakage area is obtained， and the prediction results of the formula are in good agreement with the simulation results. The simulation study on the internal pressure of the structure under fire finds that the internal pressure at ignition and the fire’s heat release rate only affect the change process of the internal pressure but has no effect on the stability value of the internal pressure. Therefore， the fire can be ignited when the internal pressure is 0Pa， so as to obtain the maximum value of the internal pressure of the fire and save the simulation time.

Key words: air-supported membrane structure; fire; internal pressure simulation; air leakage; simplified internal pressure calculation formula