Abstract: The fatigue failure of the inner liner of the IV type hydrogen storage cylinder is a key problem in the service process of the cylinder. To solve this problem, a fatigue life prediction method for IV type hydrogen storage cylinder liner is proposed. The prediction result of this method is accurate, and the error is 18.6%. Based on this, a finite element model of the type IV hydrogen storage cylinder was established, and the stress distribution and failure location of the inner liner of the HDPE at a working pressure of 1.25 MPa were analyzed, and the fatigue life of liner under different liner thickness, number of winding layers and winding layer angle was explored. The results show that the stress on the HDPE liner of hydrogen storage cylinder is concentrated at the joint of the cylinder body section and the cylinder head section; With the increasing of the thickness of the liner, the critical fatigue life of the liner increases sharply. When the thickness increases to 8mm, the liner completely enters the infinite life condition; The critical fatigue life of the liner also increases rapidly with the addition of additional spiral wound layers, and the enhancement effect is superior to the addition of additional toroidal wound layers; The critical fatigue life of the liner rapidly increased to more than 10000 times when the winding layer angle decreased from 60° to 45°.

Key words: type IV hydrogen storage cylinder, fatigue analysis, HDPE liner, finite element analysis