NESSUS allows you to treat parameters of your existing model as random variables to quantify the reliability of your design.


Powerful Interfaces

NESSUS provides direct interfaces to most popular analysis codes, including Abaqus, ANSYS, MSC Nastran, and MATLAB.

Advanced Methods

NESSUS uses some of the most advanced reliability analysis and uncertainty quantification methods available anywhere.

Cross Platform GUI

The NESSUS graphical interface is easy to use and available for various versions of Windows, Linux, and Mac OS X.


  • SetAnalysisType-200x162
  • DistributionEditor-112x162
  • FaultTree-189x162
  • Mapping-200x162
  • ParameterVariation-200x162
  • ProblemStatement-200x162
  • RandomVariables-200x162
  • ResponseCDF-200x162
  • Sensitivities-200x162

Contact Information

John McFarland, Ph.D.
Senior Research Engineer
P.O. Drawer 28510
San Antonio, Texas 78228-0510
(210) 522-3998
Fax: (210) 522-6965

David Riha
Principal Engineer
(210) 522-5221

Barron Bichon, Ph.D.
(210) 522-2129

Newest Release

Recent Events

  • AA&S & P-SAR, 3/30‐4/2/2015, Baltimore, MD
  • AeroDef, 4/20–4/23/2015, Dallas, TX
  • ASME V&V, 5/13–5/15/2015, Las Vegas, NV
  • SAMPE, 5/18–5/21/2015, Baltimore, MD
  • TMS ICME, 5/31–6/4/2015, Colorado Springs, CO
  • ASME IGTI, 6/15–6/19/2015, Montreal, CA


  • V&V Best Practices for ICME, At AA&S, Baltimore, MD
  • Intro to Probabilistic Analysis and Design, At AA&S, Baltimore, MD
  • Probabilistic Analysis and Uncertainty Quantification for Engineering Design; Methods and NESSUS Training, at SwRI

NESSUS Overview

  • NESSUS is a modular computer software program for performing probabilistic analysis of structural/mechanical components and systems.
  • NESSUS combines state-of-the-art probabilistic algorithms with general-purpose numerical analysis methods to compute the probabilistic response and reliability of engineered systems.
  • Variations in loading, material properties, geometry, boundary conditions, and initial conditions can be simulated.
  • Many deterministic modeling tools can be used such as finite element, boundary element, hydrocodes, and others.
  • NESSUS offers a wide range of capabilities, a graphical user interface, and is verified using hundreds of test problems.

NESSUS was initially developed by SwRI for NASA to perform probabilistic analysis of space shuttle main engine components. SwRI continues to develop and apply NESSUS to a diverse range of problems including aerospace structures, automotive structures, biomechanics, gas turbine engines, geomechanics, nuclear waste packaging, offshore structures, pipelines, and rotordynamics. To accomplish this, the codes have been interfaced with many well-known third-party and commercial deterministic analysis programs.

This is the website for Southwest Research Institute. If you are looking for the website for Tenable Network Security, visit

News and Releases (Release Notes)

  • NESSUS 9.8 released September 1, 2015, includes Response Surface Toolkit (RST).
  • NESSUS 9.7.4 released July 11, 2014. Minor bug fixes.
  • NESSUS 9.7 released October 28, 2013. This release adds a variety of improvements, including enhancements for GP modeling.

Southwest Research Institute

SwRI is an independent, nonprofit, applied research and development organization. Our mission is to
benefit government, industry, and the public through innovative science and technology.

Open Source Software

Portions of NESSUS rely on the OPT++ library from Lawrence Berkeley National Laboratory, licensed under the GNU LGPL.


NESSUS relies on the CENTAUR package for its random variable definitions and many of its reliability algorithms.

SwRI | CENTAUR | NASGRO | DARWIN | Integrity & Reliability Software

Benefiting government, industry and the public through innovative science and technology
Southwest Research Institute® (SwRI®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 9 technical divisions.