Structural Response of Piping to Internal Gas Detonation
Detonation waves in gas-filled piping or tubing pose special challenges in analysis and prediction of structural response. The challenges arise due to the nature of the detonation process and the role of fluid-structure interaction in determining the propagation and arrest of fractures. Over the past 10 years, our laboratory has been engaged in studying this problem and developing methodologies for estimating structural response. A brief overview of detonation waves and some key issues relevant to structural waves is presented first. This is followed by a summary of our work on the elastic response of tubes and pipes to ideal detonation loading, highlighting the importance of detonation wave speed in determining flexural wave excitation and possibility of resonant response leading to large deformations. Some issues in measurement technique and validation testing are then presented. The importance of wave reflection from bends, valves, and dead ends is discussed, as well as the differences between detonation, shock wave, and uniform internal pressure loading. Following this, we summarize our experimental findings on the fracture threshold of thin-walled tubes with pre-existing flaws. A particularly important issue for hazard analysis is the estimation of loads associated with flame acceleration and deflagration-to-detonation transition. We give some recent results on pressure and elastic strain measurements in the transition regime for a thick-wall piping, and some remarks about plastic deformation.
© 2009 by ASME. Received: April 28, 2007; Revised: December 26, 2008; Published: April 13, 2009. The results reported in this paper were obtained by a number of researchers working in my laboratories over the past decade. In particular, the bulk of the work was carried out by former students W. Beltman, T.-W. Chao (both now at Intel Corporation), and F. Pintgen (currently at GE Global Research, Nisakyuna, NY), and also current student J. Karnesky and former postdoctoral scholar Z. Liang, now at AECL, Chalk River. Term projects by students T. Curran, E. Burcsu, L. Zuhal, A. Lam, M. Zeilonka, M. Kozlowski, and A. Lew contributed important results. While working at the Caltech ASC Center, P. Hung, F. Cirak, and R. Dieterding all carried out simulations and contributed substantially to our understanding of how to design these experiments in order to carry out effective validation of simulations. Thanks to my solid mechanics colleagues W.G. Knauss, A.J. Rosakis, and G. Ravichandran for their helpful discussions and generous loans of instrumentation. This research was sponsored over the past decade by the U.S. Nuclear Regulatory Commission, by the Office of Naval Research (ONR), and by the U.S. DOE (NNSA) through the Caltech ASC project. Figures 1,3,4,5,6,7 reproduced by kind permission of Elsevier Publishing. Figures 8,9,12 reproduced with kind permission of Springer Science and Business Media.
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