Provided are a method and a system for optimizing a design of a high-pressure hydrogen storage composite wound gas cylinder. The method includes: S1, determining a preliminary design result according to a film theory and a grid theory; S2, establishing a three-dimensional solid refined model of the preliminary design result based on a finite element analysis software; and S3, applying the three-dimensional solid refined model for a simulation analysis, and applying a response surface or a genetic algorithm for an optimization design.

The present disclosure relates to at least one method for ascertaining at least one attribute of pressure vessel wall. A method comprises: while a pressure vessel, which comprises a wall having an outer surface and an inner surface, is operating: ascertaining a current wavelength shift of a first fiber Bragg grating (FBG) sensor disposed at a first outer surface location on the pressure vessel; and ascertaining a current thickness of the wall at the first outer surface location by: computing a vector based on a time series of the current wavelength shift, or a derivative of the time series, or a derivative of the current wavelength shift; providing the vector to a predetermined regression model; and using the regression model, ascertaining the current thickness of the wall.