Tube collapse under combined external pressure, tension and bending

Abstract

Finite element analyses of the collapse behaviour for long, relatively thick-walled metal tubes are presented under combined external pressure, tension and bending loads. The effects of initial ovality, residual stress, strain-hardening, yield anisotropy and load paths have been accounted for in the analyses. The analysis procedure has been validated using experimental results. Collapse envelopes for thick tubes under combined external pressure, tension and bending loads are presented in the form of pressure-moment-tension interaction, pressure-tension-curvature interaction and pressure-axial strain-curvature interaction. Factors affecting collapse envelopes are identified by means of parametric studies. Interaction equations to predict collapse envelopes are proposed based on the present finite element analyses considering major factors. The interaction equations are verified against finite element results and good agreement has been achieved for tubes with various geometric and material parameters and initial imperfections.