Tank production method and tank

Abstract

A tank production method for preventing generation of non-uniform stacked portions in a sheet layer while securing the strength of the tank, the method including a winding step of winding resin-impregnated fiber sheets to form a sheet layer with a predetermined thickness. The winding step includes divided winding steps of winding divided fiber sheets obtained by dividing a fiber sheet into a plurality of divided fiber sheets having a length shorter than the length required to form the sheet layer with the predetermined thickness. The second divided winding step or each of the second and following divided winding step satisfies an Inequality: X>(σ·t·L)/(A·W), where an overlapped length of the start end of a new divided fiber sheet stacked on the terminal end of the divided fiber sheet wound in the preceding divided winding step is X, the tensile stress applied to the tank in the circumferential direction thereof is σ, the thickness and width of each divided fiber sheet are t and W, respectively, the length of a cylindrical portion of the tank is L, and the shearing strength of the resin is A.

1 - 2 . (canceled) 
     
     
         3 . A tank comprising a sheet layer with a predetermined thickness,
 wherein:   the sheet layer includes a plurality of divided fiber sheets that have been stacked by being wound on the tank along a circumferential direction thereof and integrated by resin, and   an Inequality: X>(σ·t·L)/(A·W) is satisfied, where an overlapped length of a start end of a divided fiber sheet on an upper layer side that is stacked in an overlapped manner on a terminal end of a divided fiber sheet wound on a lower layer side is indicated by X, the tensile stress applied to the tank in a circumferential direction thereof is indicated by σ, a thickness and width of each divided fiber sheet are indicated by t and W, respectively, a length of a cylindrical portion of the tank is indicated by L, and a shearing strength of the resin is indicated by A.