On the Adequacy of Shell Models for Predicting Stresses and Strains in Thick-Walled Tubes Subjected to Detonation Loading
This paper analyzes the adequacy of shell models for predicting stresses and strains in thick-walled tubes subjected to detonation loads. Of particular interest are the large axial strains which are produced at the inner and outer surfaces of the tube due to bending along the tube axis. First, comparisons between simple shell theory and a static finite element model are used to show that the axial strain varies proportionally with wall thickness and inversely with the square of the axial wavelength. For small wavelengths, this comparison demonstrates nonlinear behavior and a breakdown of the shell model. Second, a dynamic finite element model is used to evaluate the performance of transient shell equations. This comparison is used to quantify the error of the shell model with increasing wall thickness and show that shell models can be inaccurate near the load front where the axial curvature is high. Finally, the results of these analyses are used to show that the large axial strains which are sometimes observed in experiments cannot be attributed to through-wall bending and appear to be caused instead by non-ideal conditions present in the experiments.
© 2013 by ASME. This work was motivated by findings of the research program carried out for the Hydrogen in Pipes and Ancillary Vessels (HPAV) study for the Hanford Waste Treatment Plant. Greg Jones of the US Department of Energy, Office of River Protection, Hanford WA, was the technical program manager for the portion of the work done at Caltech. The senior author (JES) benefited from discussions on detonation loading of piping with the members of the HPAV team over the period 2005-2012 while he was associated with the HPAV study. In particular, he would like to acknowledge the very substantial contributions to his understanding of the through-wall bending issue by John Minichiello of Bechtel National Inc, as well as Tom Ligon and David Gross of Dominion Engineering. The present work was funded entirely by the California Institute of Technology; we thank the Office of the Provost and the benefactors of the C.L. "Kelly" Johnson Professorship.
Published - PVP2013-97148.pdf