Powder metal jet penetration into stressed rock

The Uintah computational framework (UCF) has been adopted for simulation of shaped charge jet penetration and subsequent damage to geological formations.  The Kayenta geomechanics model, as well as a simplified model for shakedown simulations has been  incorporated within the UCF and is undergoing extensive development to enhance it to account for fluid in pore space.

A generic penetration simulation using Uintah

The host code (Uintah) itself has been enhanced to accommodate  material variability and scale effects. Simulations have been performed that import flash X-ray data for the velocity and geometry of a particulated metallic jet so that uncertainty about the jet can be reduced to develop predictive models for target response.  Uintah’s analytical polar decomposition has been replaced with an iterative algorithm to dramatically improve accuracy under large deformations.

Higher order integration of the time step (via more accurate evaluation of the exponential of a tensor) has furthermore significantly alleviated occurance of negative Jacobians common to this class of problem. The CPDI alternative to rectangular GIMP domains in the Material Point Method has been developed and shown to dramatically improve accuracy and robustness of simulations involving massive deformations. An enrichment algorithm for modeling weak discontinuities (jumps in strain) across surfaces contained within low-order grid elements has been developed and shows very good promise to generalize to accurately enforce traction boundary conditions and to allow formation of cracks without having to explicitly track newly forming surfaces has been developed, both of which are challenging in particle methods.

UofU Contributors/collaborators:

Alireza Sadeghirad (Postdoc, Mech. Engr., UofU)
Seubpong Leelavanichkul (Research Associate, UofU)
Tim Fuller (PhD 2010 Mech. Engr. UofU, now Sandia Labs researcher)
Jeff Burghardt (PhD student, Mech. Engr., UofU)
Michael Homel (PhD student, Mech. Engr., UofU)

Krishna Kamojjala (PhD student, Mech. Engr., UofU)

External collaborators/mentors:
Jim Guilkey (Researcher, Schlumberger, and Research Prof, ME, UofU)

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