SEDL / STP / STP1321-EB / STP12321S

Fatigue Analysis of a Vessel Experiencing Pressure Oscillations

Troiano, E
Research Engineer, US Army Research Development and Engineering Center, Benet Laboratories, Watervliet, New York

Underwood, JH
Research Engineer, US Army Research Development and Engineering Center, Benet Laboratories, Watervliet, New York

Scalise, A
Research Engineer, US Army Research Development and Engineering Center, Benet Laboratories, Watervliet, New York

O'Hara, GP
Research Engineer, US Army Research Development and Engineering Center, Benet Laboratories, Watervliet, New York

Crayon, D
Mechanical Engineering Technician, US Army Research Development and Engineering Center, Benet Laboratories, Watervliet, New York

Pages: 14    Published: Jan 1997

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Abstract

A pressure vessel, designed and tested under laboratory conditions for tens of thousands of cycles, failed in service after only a few cycles. Thousands of oscillatory pressure reversals have been measured at each loading. However, the predominance of the stress amplitudes were well below the critical threshold values necessary to initiate fatigue cracking.

Analysis has demonstrated that the disparity between lab cycling and field loading conditions cannot be explained simply by mechanical loading alone. Further investigation into the problem revealed that an extremely aggressive environment, the by-products of the internal combustion from within the pressure vessel, along with high temperatures, pressures, and other sources of high tensile loading all contribute to the short fatigue life of the vessel.