Within the Advanced Simulation and Computing (ASC) program, the Integrated Codes area develops and improves predictive simulation tools to support U.S. stockpile stewardship. These large-scale codes incorporate physics and engineering models and specialized codes to predict, with reduced uncertainty, the behavior of weapons and their components in a variety of environments. In addition to supporting the stockpile, a number of other national security missions use these simulation tools for innovative product engineering.

Engineering Physics Integrated Codes

Sierra Mechanics

Sierra is Sandia’s engineering mechanics simulation code suite. This suite includes coupled simulation capabilities for thermal, fluid, aerodynamics, solid mechanics and structural dynamics. We use these simulation capabilities to predict the performance of a weapon system in normal operation as well as the response of a system in abnormal environments, such as a crash or fire.


The Radiation Analysis Modeling and Simulation of Electrical Systems (RAMSES) code suite provides simulation capabilities for radiation, electrical, and electromagnetic effects. This capability allows us to predict the reliability and survivability of weapon systems and components when exposed to hostile radiation environments and electromagnetic insults, including lightning strikes. Component modules of RAMSES include Xyce (electrical), Charon (electronic device), ITS and CEPTRE (coupled electron-photon radiation transport), and Eiger (electrostatic).


ALEGRA codes simulate large deformations and strong shock physics including solid dynamics in an Arbitrary Lagrangian-Eulerian methodology as well as magnetics, magnetohydrodynamics, electromechanics and a wide range of phenomena for high-energy physics applications.


CTH is a multi-material, large deformation, strong shock wave, solid mechanics code. It has models for multi-phase, elastic, viscoplastic, porous and explosive materials.

Specialized Codes and Libraries


CUBIT is a full-featured software toolkit for robust generation of two- and three-dimensional finite element meshes. Its main goal is to reduce the time to generate meshes, particularly large hex meshes of complicated, interlocking assemblies. As a solid-modeler based preprocessor, it meshes volumes and surfaces for finite element analysis.


Trilinos is an extensive open source software library that provides users with a variety of solvers for use on parallel computers. A distinguishing feature of Trilinos is its focus on packages and its emphasis on abstract interfaces for maximum flexibility in component interchanging. Many applications are standardizing on Trilinos application programming interfaces (APIs), which gives them access to all Trilinos solver components without any unnecessary interface modifications.


The Design Analysis Kit for Optimization and Terascale Applications (DAKOTA) toolkit provides a flexible, extensible interface between analysis codes and iterative systems and analysis methods. Using this toolkit, simulations developed for structural mechanics, heat transfer, fluid mechanics, shock physics and many other fields of engineering become design tools. More than just single point predictions, simulations are used for automated determination of system performance improvements throughout the product lifecycle.

Integrated Analysis Workbench

The Integrated Analysis Workbench is an integrated software product that provides model management and analysis. Projects and technologies include tools for optimized problem set-up and meshing, metadata and scientific data management, workflow management, and access control.

Applications and Algorithms Research

In order to continue developing of state-of-the art computer simulation capabilities, we are performing fundamental research in computational methods, advanced analytics, systems analysis and transformational technologies. These efforts include large-scale problem solving (e.g., behavior at the micro and macro scales in both space and time) using extensive processor scalability (e.g., over 1,000,000 cores).

Next Generation Architectures, Codes, and Applications

The next generation of supercomputing will require significant development of codes, code architectures, and applications development in order to provide leading edge simulations capabilities. Research in this project area includes porting current codes to new production platforms to study scalability, development of mini-applications to study performance in new programming models on novel computing hardware, and creating agile code components that adapt easily to new architectures.