Advanced science.  Applied technology.


NESSUS 9.8 Release Notes


NESSUS 9.0 and newer bring many new enhancements. With NESSUS 9.5, the graphical interface has been reworked to greatly simplify the process of setting up and solving a problem. NESSUS 9.7 introduces a variety of enhancements, including improved support for working with Gaussian Process response surface models, as well as a new dynamically linked user-defined model type. The following list provides an overview of the highlights in these releases.

New Capabilities and Enhancements

New in Version 9.8

  • Added the NESSUS Response Surface Toolkit, a standalone application for designing, fitting, assessing, and visualizing response surface models
  • Minor improvements to response extraction for the Abaqus interface

New in Version 9.7.4

  • Fix for bug with small LHS sample sizes
  • Fix for locating ext_cmd.cfg on Windows
  • Changes to arguments for running NESSUS from command line

New in Version 9.7

  • Gaussian Process model enhancements:
    • GP model definition saved to file for later re-use without needing to re-fit the model
    • Options for defining and fitting observation noise level
  • New capability to define models using dynamically linked libraries
  • Monte Carlo simulation now supports all distribution types
  • Use of Sobol sequences for global sensitivity analysis to significantly increase efficiency
  • Added p-level and full CDF capabilities for EGRA
  • Updated installation layout for Windows 7 compatibility
  • Fixes for beta distribution
  • Increased limit on number of runs in Deterministic Analysis mode

New in Version 9.6.4

  • Improved error messages for variable mapping with external models
  • Fixes for Matlab interface
  • Added endcycle to WCN function argument list. This variable defines the number of cycles for the endurance limit.

New in Version 9.6.3

  • Improved compatibility with Windows 7 (elevated permissions not required)
  • Minor bug fixes

New in Version 9.6.2

  • Changed GP regression model and RSM_GP method to build GP model with linear trend function instead of constant

New in Version 9.6.1

  • Added polynomial coefficients and goodness of fit statistics to *.out file for regression models
  • Updated Abaqus interface to work with version 6.11
  • Several minor bug fixes for the GUI

New in Version 9.6

  • New capability for global sensitivity analysis using variance decomposition
    • Identify important variables based on their contribution to total variance of the model response
    • Three variance decomposition analysis methods are provided
  • New wizard for pasting and importing data into NESSUS tables
  • Bug fixes:
    • Fixed error when running LHS with triangular distribution
    • Fixed bug when using deterministic analysis with deterministic variables

New in Version 9.5.5

  • CTH interface enhancements and bug fixes:
    • Corrected issue with checking for existing error file for latest compilers
    • Defines last time response value for the restart database when the response is a time history file
  • Enhancements and bug fixes for the WCN model:
    • Added user definition for cycles corresponding to the endurance limit
    • Improved checks for a, c, and K validity limits

New in Version 9.5.4

  • Bug fixes for Abaqus displacement response extraction

New in Version 9.5.3

  • New regression model: Gaussian Process
  • NASTRAN results enhancements:
    • Ability to work with larger models
    • Capabilities for composite materials, including composite failure indices
    • User-defined datablock name
    • Debug option
  • Bug fixes to use correct response level with EGRA and ISMPP

New in Version 9.5

  • Simplified outline layout
    • Problem Definition node begins with problem statement definition instead of system definition (now Fault Tree Definition)
    • Fault Tree, Correlations, and Confidence Bounds are now accessed via popup windows instead of separate outline nodes
    • Consolidated "Deterministic Analysis" and "Parameter Variations Analysis"
    • Consolidated probabilistic analysis type and method configurations
    • Simplified procedure for running analyses and viewing results
  • Improved interfaces for generating finite difference step sizes and deterministic input values (parameter variations)
  • Inverse reliability analysis support for RSMGP
  • Additional advanced options for EGRA
  • Fix for triangular distribution

New in Version 9.1

  • Improved distribution editing interface
    • PDF equations displayed in the GUI
    • Short descriptions of distribution parameters in GUI
  • Support for MacOS X
  • Miscellaneous minor bug fixes

New in Version 9

  • New Reliability Analysis Methods
    • ISMPP: Importance sampling at user-defined MPP
    • EGRA: State-of-the-art surrogate-based method designed for extremely expensive response functions. Unlike MPP-based methods, it is not gradient-based
    • RSMGP: Gaussian process surrogate method
  • LHS enhancements (advanced options)
    • Optimal design based on max-min distance criterion
    • 3 correlation reduction methods for small samples
    • Capability to augment (double) sample size while maintaining Latin Hypercube structure
  • Probability distribution modeling
    • New distributions: beta, exponential GEVmax, GEVmin, gamma, Pareto, triangular, uniform
    • Capability to switch between definition in terms of natural parameters or mean & standard deviation

Operating Systems

  • Windows (XP, Vista, 7)
  • Linux
  • Mac OS X