Mechanical comprehensive evaluation model and sealing performance research of rubber cylinder at large pressure and high temperature

The submarine pipe stopper is prone to failure at large pressure and high temperature conditions. This work focuses on the submarine pipe stopper's sealing failure caused by excessive shear stress and high temperature. First, the working principle of the sealing device in the stopper was analyzed and its performance was verified through land and sea trials. Then a comprehensive evaluation model fit for the large working pressure was established by analyzing the rubber cylinder's sealing performance and strength. Next, the model was modified by simulation using the nitrile rubber (NBR) cylinder and the fluororubber (FKM) cylinder were used as examples to revise the comprehensive evaluation model while taking temperature into account. The maximum contact stress and the maximum shear stress of the NBR rubber cylinder at 100 degrees C increased by 28% and 30.62% compared to 25 degrees C, and that of the FKM rubber cylinder increased by 24% and 26.12%. In comparison to 25 degrees C, the maximum contact stress and maximum shear stress of the NBR rubber cylinder increased by 28% and 30.62% at 100 degrees C, while the FKM rubber cylinder had an increase of 24% and 26.12%. At 100 degrees C, the NBR rubber cylinder exhibits a maximum contact stress of 4.71 MPa and a maximum shear stress of 1.18 MPa, whereas the FKM rubber cylinder displays maximum contact and shear stresses of 5.09 and 2.44 MPa. Finally, the rubber cylinder's maximum working pressure at different temperatures was derived, and the influence of its parameters was discussed. The maximum working pressure at 100 degrees C is only 21% of what the rubber cylinder can bear at 25 degrees C. This work is of great significance for accurately evaluating the rubber cylinder's sealing performance in the submarine pipe stopper and provides new ideas for the rubber cylinder's design at high-temperature conditions.