The effect of static rupture pressure (pST) on overpressure loadings caused by gasoline-air mixture deflagration was obtained based on experimental research in a vessel with a weak roof. The results showed that Δp-t profiles under different pST were divided into four types

and the main overpressure peaks were burst peak (Δp1)

vent flow peak (Δp2)

external deflagration peak (Δp3) and locally instable combustion peak (Δp4). The maximum overpressure peak inside the vessel was Δp3 when pST was greater than or equal to 2.5 kPa

however

the maximum overpressure peak was Δp1 when pST was greater than or equal to 5 kPa and less than or equal to 30 kPa. For the external overpressure

the maximum overpressure peak was Δp3. Induced by the coupling of external deflagration and negative pressure

pressure oscillation occurred when pST was greater than or equal to 2.5 kPa and less than or equal to 20 kPa

and the frequency as well as the duration of pressure oscillation were related to pST. Duration of burst stage showed an increasing trend with the increase of pST

while duration of venting stage

external deflagration stage

and pressure oscillation stage showed an opposite trend. The value of internal and external overpressure peaks were both proportional to pST. With the increase of the pST

the internal pressure peak Δp1 and Δp2 increased in linear and the external pressure peak Δp3 increased in quadratic.