Multiphysics modeling of the initiating capability of detonators. I. The underwater test

Detonators are explosive devices used for the initiation of secondary explosives in commercial and military applications. They are characterized by their initiating capability, which is a critical factor for their safe and effective use but challenging to assess accurately. In this two-part study, we employ numerical simulations to investigate the blast wave generated by detonators and examine their initiating capability. The first part, presented here, follows the European underwater test of initiating capability, which evaluates detonators in isolation (direct method) and the second part considers detonators placed within a receiving explosive charge (indirect method). In the underwater test, the detonator is ignited inside a water tank and the initiating capability is assessed through pressure measurements in the far field. We employ a multiphysics methodology that allows the use of distinct mathematical models for each component such as two-phase reactive materials, elastic–plastic solids, and inert fluids. The computational implementation is validated against underwater experiments and is employed for the simulation of the blast wave generated by different types of detonators. The initial focus is on the general characteristics of the blast wave and subsequently on the differences between detonators of different shell material and thickness. Results show that the blast wave in the near field is asymmetric and varies significantly between detonators, but these features do not persist in the far field. The underwater test considers only the far field and is thus unable to capture the near field differences, which have a significant impact on the initiation of secondary explosives.

[1]  Nikolaos Nikiforakis,et al.  Multiphysics modeling of the initiating capability of detonators. II. Booster initiation , 2021 .

[2]  C. Handley,et al.  Understanding the shock and detonation response of high explosives at the continuum and meso scales , 2018 .

[3]  Craig M. Tarver,et al.  Detonation waves in pentaerythritol tetranitrate , 1997 .

[4]  T. Klapötke,et al.  Determination of the Initiating Capability of Detonators Containing TKX‐50, MAD‐X1, PETNC, DAAF, RDX, HMX or PETN as a Base Charge, by Underwater Explosion Test , 2016 .

[5]  H. Brode Blast Wave from a Spherical Charge , 1959 .

[6]  P. Harris,et al.  Reflectivity of a shock front in water and nitromethane , 1984 .

[7]  S. Godunov,et al.  Elements of Continuum Mechanics and Conservation Laws , 2003, Springer US.

[8]  G. Taylor The formation of a blast wave by a very intense explosion I. Theoretical discussion , 1950, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[9]  H. S. Udaykumar,et al.  Ghost Fluid Method for Strong Shock Interactions Part 1: Fluid-Fluid Interfaces , 2009 .

[10]  B. Lambourn,et al.  On the systematics of particle velocity histories in the shock-to-detonation transition regime , 2006 .

[11]  H. James An Extension to the Critical Energy Criterion used to predict shock initiation thresholds , 1996 .

[12]  P. Lax,et al.  On Upstream Differencing and Godunov-Type Schemes for Hyperbolic Conservation Laws , 1983 .

[13]  E. Lozano,et al.  Characterizing the energy output generated by a standard electric detonator using shadowgraph imaging , 2017 .

[14]  Jeffrey W. Banks,et al.  A high-resolution Godunov method for compressible multi-material flow on overlapping grids , 2006, J. Comput. Phys..

[15]  Interactions of Inert Confiners with Explosives , 2006 .

[16]  C. M. Tarver,et al.  Phenomenological model of shock initiation in heterogeneous explosives , 1980 .

[17]  Ralf Deiterding,et al.  Eulerian adaptive finite-difference method for high-velocity impact and penetration problems , 2013, J. Comput. Phys..

[18]  M. Greenspan,et al.  Speed of sound in water by a direct method , 1957 .

[19]  C. Tarver Corner turning and shock desensitization experiments plus numerical modeling of detonation waves in the triaminotrinitrobenzene based explosive LX-17. , 2009, The journal of physical chemistry. A.

[20]  John H. S. Lee The Detonation Phenomenon: Contents , 2008 .

[21]  Nikolaos Nikiforakis,et al.  A hybrid formulation for the numerical simulation of condensed phase explosives , 2016, J. Comput. Phys..

[22]  Nikolaos Nikiforakis,et al.  A multi-physics methodology for the simulation of reactive flow and elastoplastic structural response , 2017, J. Comput. Phys..

[23]  Nikolaos Nikiforakis,et al.  Numerical modelling of underwater detonation of non-ideal condensed-phase explosives , 2015 .

[24]  Craig M. Tarver,et al.  Ignition and Growth Modeling of LX‐17 Hockey Puck Experiments , 2005 .

[25]  Yongmin Zhang,et al.  Signal Analysis and Waveform Reconstruction of Shock Waves Generated by Underwater Electrical Wire Explosions with Piezoelectric Pressure Probes , 2016, Sensors.

[26]  Phillip Colella,et al.  A high-order Eulerian Godunov method for elastic-plastic flow in solids , 2001 .

[27]  Grégoire Allaire,et al.  A five-equation model for the simulation of interfaces between compressible fluids , 2002 .

[28]  Keh-Ming Shyue,et al.  Regular Article: A Fluid-Mixture Type Algorithm for Compressible Multicomponent Flow with van der Waals Equation of State , 1999 .

[29]  Dimitris Drikakis,et al.  An Eulerian method for multi-component problems in non-linear elasticity with sliding interfaces , 2010, J. Comput. Phys..

[30]  William D. Henshaw,et al.  A study of detonation diffraction in the ignition-and-growth model , 2006 .

[31]  J. Tiffany,et al.  Factors Affecting Initiating Efficiency of Detonators. , 1945 .