Plastic Collapse of Oval Straight Tubes Under External Pressure

Abstract

Experimental and theoretical results are presented for the collapse pressure of long straight slightly oval Inconel tubes under external pressure with dimensions used in heat exchangers for nuclear power plants. Since the tubes are in the thick-walled category, plastic effects are significant. Plastic limit analysis methods are utilized to obtain an expression for the collapse pressure which is exact for the idealized tube and which correlates well with the test data. The expected imperfection sensitivity is displayed by the significant drop of the collapse pressure for small increases in ovality.