The conservation equations of mass, momentum, and energy are the basis for that branch of physics known as continuum mechanics. A basic assumption of continuum mechanics allows an analyst to treat the deformation of a material at a discrete point as if the material was continuous.  Corvid uses its tools to solve the conservation equations of mass, momentum, and energy in an energy regime where large deformations, high strain rates, and/or strong shocks occur.  While these tools are known colloquially by the terms:  Hydrocode, Hydro-Structural Solver, Finite Element Solver, etc….they are more correctly described as shock physics analysis packages. 

 

Shock Physics encompasses regimes of material phenomena such as:

 

1. (U) High Strain Rate

           a. Perforation

           b. Penetration

           c. Large material deformation

           d. Vaporization

           e. Fracture

2. (U) Lower Strain Rate

           a. Bending

           b. Small Deformation

3. (U) Reactive materials

           a. High Explosives

           b. Propellants

 

Modeling these types of phenomena requires knowledge of material response under various amounts of deformation and at different rates (e.g. static versus dynamic).  Some materials, such as ceramics and high strength steels, are brittle and show insignificant amounts of deformation at both low and high strain rates.  Ductile materials, such as mild steels and aluminums, can undergo plastic (irreversible) deformation prior to fracture, and the stress-strain behavior of these materials can vary for increasing strain rates.  Another material type includes “stretchy materials,” such as polymers, metals at high temperatures, propellants, and explosives, which exhibit viscoelasticity, or both viscous and elastic behaviors.

 

Corvid has extensive experience and subject matter expertise in these areas as applicable to DoD systems.