Stress of a Spirally Corrugated Shell Subjected to Internal Pressure

Abstract

A sheath of electric cable must endure the pressure of the cooling oil flowing through it. This report gives a method for calculating the stress distribution in a spirally corrugated tube subjected to a uniform internal pressure. The method of analysis is based on a general bending theory for shells, and is applicable also to a tube with corrugation of U or Ω type. Among components of Stress appearing in the wall, the largest one in its absolute value is the direct stress at the trough in the direction of spiral. This value becomes larger as the radius becomes larger, and shows little variations with the wave height of corrugation. The shearing stress and the twisting moment are nearly proportional to the pitch of the spiral, but other stress resultants and moments hardly depend on it. The maximum stress calculated for the cable sheath of the standard type is nearly equal to the value obtained from the theory for shells of revolution.