Mesoscale calculations of the dynamic behavior of a granular ceramic

Abstract

Mesoscale calculations have been conducted in order to gain further insight into the dynamic compaction characteristics of granular ceramics. The primary goals of this work are to numerically determine the shock response of granular tungsten carbide and to assess the feasibility of using these results to construct the bulk material Hugoniot. Secondary goals include describing the averaged compaction wave behavior as well as characterizing wave front behavior such as the strain rate versus stress relationship and statistically describing the laterally induced velocity distribution. The mesoscale calculations were able to accurately reproduce the experimentally determined Hugoniot slope but under predicted the zero pressure shock speed by 12%. The averaged compaction wave demonstrated an initial transient stress followed by asymptotic behavior as a function of grain bed distance. The wave front dynamics demonstrate non-Gaussian compaction dynamics in the lateral velocity distribution and a power-law strain rate-stress relationship.

Shock-induced formation of a disordered solid from a dense particle suspension

“…Similarly of interest, under dynamic loading, is the role of force chains in the response of shock-loaded granular beds, where force chains are formed and destroyed at the mesoscale [6].…”

High resolution simulations of energy absorption in dynamically loaded cellular structures

“…Figure 17 shows the results of loading a rod structure at velocities increasing from 0.3 to 0.9 mm µs −1 . The simulations clearly show that as the impact velocity is increased beyond 0.5 mm µs −1 there is a transition from a mechanism dominated by roughly uniform lateral flow to one domi- [28]. These workers did not observe microjetting in their simulations.…”

“…Significant computing resources can be saved in the simulation of cellular structures if a "pseudo 1D" modelling scheme similar to that employed in simulations by Borg and Vogler [28] is adopted. Consider a cylindrical sample made up of a regular cellular structure in which the diameter of the sample is much greater than its thickness.…”

“…The effects of material strength on material response may also be modelled using strength models such as Steinberg-Guinan [31] and . CTH has been successfully applied to the study of granular ceramic materials impacted in a velocity regime similar to that discussed in this paper [28]. The CTH code contrasts with implicit finite element codes in which the main aim is to simulate the response of materials in the low strain rate regime where the response of material is dominated by strength rather than by inertial effects.…”

Mesoscale simulations of granular materials with peridynamics

“…Insight into the fine scale behavior relevant to the dynamic response of granular materials via computational mesoscale modeling at the scale of grains was pioneered by Benson [3] and later explored using Eulerian hydrodynamic calculations [4][5]. While the results of these studies have shown general agreement with experiment, the Eulerian framework lacks grain-to-grain contact dynamics and fracture.…”