Patent ID: 8458988

Claim:
A method of producing a thin wall profile member, comprising the steps of: providing a thin wall profile member having a cross section including at least one of (1) at least two main strips and at least one additional strip having ends connecting with respective ends of two of said main strips, and selecting cross section dimensions such that said main strip has a thickness δ b and a width b, said additional strip has a thickness δ a and a width a, and δ b /b is no larger than δ a /a, and (2) at least one main strip and at least one additional strip having one end connecting with an end of said main strip, said main strip having a thickness δ b and a width b, said additional strip having a thickness δ c , and a width c, and δ b /b being no larger than δ c /c; selecting range values of cross section dimensions ratios for the thin wall profile member and various ratio values within the range values; determining for the thin wall profile member a plurality of shape efficiency factor values Σ 1 , Σ 2 . . . Σ n based on the selected ratio values within the range values, wherein each of the shape efficiency factor values is determined as Σ= K f ·K m , where: K f =(i 2 /F) 2/5 , is an overall stability factor, K m =K 1/5 /(b/δ b ) 2/5 , is a local stability factor, b, δ b , are the width and the thickness of said main strip, respectively, i, F, are the radius of gyration and the area of said cross section, respectively, and K is the coefficient in the known formula for local stability critical stress; finding within the plurality of the shape efficiency factor values Σ 1 , Σ 2 . . . Σ n for the thin wall profile member, a maximum shape efficiency factor value Σ max ; ascertaining the ratio values for the thin wall profile member which resulted in the maximum shape efficiency factor value Σ max ; and producing the thin wall profile member with the ratio values which resulted in the maximum shape efficiency factor value Σ max , so as to ensure a reliable operation of the thin wall profile member with a minimal weight.