S. S. Volkov, V. V. Struzhanov
OPTIMAL WALL THICKNESS OF METAL PIPE ENCASED IN A FIBER POLYMER SHELL
An algorithm for calculating the parameters of a compound cylinder with a metal casing and a fiber polymer shell is developed. The inner radius of the casing and the outer radius of the compound cylinder are limited by technological conditions. The compound cylinder under internal pressure deforms as a single unit. It is assumed that the thickness of the metal wall of the casing should be minimized. With the application of the Lamé problem, an optimal relationship between the thickness of the casing and the thickness of its reinforcing shell is determined. Various strength conditions in the critical points of the structure are analyzed and the most comprehensive condition is chosen. An exact analytical solution of the problem is found. The ratio of two radii of a compound cylinder is found through a system of equations that relates the strength condition to the strain compatibility condition at the junction between the casing and the shell. The wall thickness for a closed cylinder with a metal casing and an open fiber polymer shell is calculated as a numerical example.
Keywords: compound cylinder, internal pressure, the Lamé problem, exact solution, polymer fiber, safety factor
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