EXOS: A Software Package for 3-D Simulation of Impact Dynamics

Computing & Wireless : Application Software

Available for licensing


  • Eric Fahrenthold, Ph.D. , Mechanical Engineering

Background/unmet need

A variety of software packages, such as CTH, DYNA3D, and SPHINX, have been developed by government and industry researchers for three-dimensional simulation of impact dynamics, primarily for aerospace and defense applications. Despite their success, many of these programs exhibit diffusion or stability problems in hypervelocity impact applications. Researchers at The University of Texas at Austin have developed a software package called EXOS that avoids these issues, by using a fully Lagrangian form of the equations for the program. EXOS applies Hamilton’s equations to a system of hybrid particle-elements in order to obtain a three-dimensional model for shock physics simulations. The use of a fully Lagrangian frame of reference also means that no mixing or partial pressures is needed to represent the multi-material case.

Invention Description

EXOS is a physics-based code designed to simulate a wide variety of three-dimensional impact dynamics problems, such as the effects of weapons on vehicular protection systems or meteor-debris impact damage to satellites. It includes a preprocessor subprogram, an analysis code, and a simple rezoner subprogram in order to model hypervelocity impact problems.

EXOS was developed using FORTRAN programming language and is compatible with many different hardware configurations and operating systems, ranging from personal computer to supercomputer. EXOS is energy-based and hence simple to formulate, with no need to consider continuum balance laws, interpolation functions, or weighted residual solution techniques. This technology is an improved version of the original EXOS and includes models of fabrics, mixtures, and porous materials. It is also able to accept hex mesh geometries.


  • Employs novel hybrid particle finite element method
  • Includes models for fabrics, mixtures, and porous materials
  • Accepts hex mesh geometries


  • Simple to formulate
  • Compatible with many different hardware configurations and operating systems

Market potential/applications

 Engineering analysis code, aerospace companies, and defense companies

Development Stage

Beta product/commercial prototype