A Virtual Test Facility for Simulating Detonation-and Shock-Induced Deformation and Fracture of Thin Flexible Shells

Abstract

The coupling of a dynamically adaptive Eulerian Cartesian detonation solver with hierarchical time step refinement to a Lagrangian thin-shell finite element solver with fracture and fragmentation capabilities is presented. The approach uses a level set function to implicitly represent arbitrarily evolving solid structures on the Cartesian mesh. The auxiliary algorithm used to efficiently transform the shell solver mesh on-the-fly into a distance function is sketched briefly. We detail the derivation of the employed engineering combustion model that eliminates the numerical stiffness otherwise inherent to detonation waves and describe our approach to modeling fracture. The thin-shell solver utilizes a subdivision finite element discretization and achieves element separation with interface edges and a cohesive law. For method validation and benchmarking, the simulation of the deformation of a circular thin copper plate under impulsive pressure loading is presented. As a realistic computational application, we consider a three-dimensional setup in which the passage of an ethylene-oxygen detonation wave induces large plastic deformations and rupture of a thin-walled tubular specimen made of aluminum. Special attention is paid to the verification of the hydrodynamic loading conditions. The computational fluid-structure interaction results are found to be in agreement with experimental observations.

Dynamical separation of spherical bodies in supersonic flow

“…Numerical approach As in Laurence & Deiterding (2011), we employ the Cartesian fluid solver framework AMROC (Deiterding 2005b;Deiterding et al 2005Deiterding et al , 2007Deiterding 2009Deiterding , 2011aZiegler et al 2011) to simulate numerically the fluid-structure interaction of the free-flying spherical bodies. The equations solved to model the inviscid compressible fluid are the Euler equations in conservation-law form…”

Investigation of shock focusing in a cavity with incident shock diffracted by an obstacle

“…In order to obtain deeper insight into the experiments, the Cartesian shock-capturing solver system AMROC V2.0 [25] within the freely available Virtual Test Facility software [26] was adopted. A variety of discretizations are implemented in AMROC, and in this study we have utilized a WENO method with third-order accuracy in space and time.…”

Adaptive high‐resolution simulation of realistic gaseous detonation waves

“…A detailed description of the value construction for Eq. (1) can be found in [6]. As the numerical approximation of detonation waves requires a high temporal and spatial resolution particular near the detonation front, we have incorporated the finite volume scheme into the adaptive mesh refinement (AMR) method after Berger and Collela [7] that uses a hierarchy of successively refined sub-grids together with recursive time step refinement.…”

“…The AMR method has been implemented generically in a parallel, dimension-independent framework in C++. See [6] for details.…”