Linear/Nonlinear Reduced-Order Substructuring for Uncertainty Quantification and Predictive Accuracy Assessment

  • Timothy Hasselman
  • George Lloyd
  • Ryan Schnalzer
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)


Modal testing is routinely performed on space craft and launch vehicles to “verify” (calibrate and validate) analytical models. Large multi-component structures such as the Space Transportation System (STS) or “Space Shuttle,” and the newly proposed NASA Space Launch System (SLS), are impractical to test in their assembled configurations. Alternatively, substructure testing of these multi-component structures has been performed and used to calibrate/validate analytical models of the substructures, which are then assembled to analyze system response to applied loads. This paper describes a methodology applicable to uncertainty quantification (UQ) of reduced (modal) models of linear (or linearized) finite element models of substructures, as well as reduced (stochastic neural net (SNN)) models of nonlinear substructures, such as joints. The UQ at reduced substructure levels is propagated to higher levels of assembly by efficient means, enabling predictive accuracy assessment at the coupled system level. UQ is based entirely on comparisons on analysis and test data at the substructure level so that recourse to the specification and quantification of element-level random variables is not necessary. Examples are presented to illustrate the methodology.


Uncertainty quantification Linear and nonlinear substructuring Reduced-order models component mode synthesis Stochastic neural networks Uncertainty propagation Predictive accuracy assessment 



This work has been supported by the Jet Propulsion Laboratory of Pasadena, California under a NASA STTR contract. The authors wish to thank Dr. Lee Peterson as COTR for his support and guidance on the project which addresses the quantification of margins and uncertainties (QMU) for integrated spacecraft systems. The authors also acknowledge the technical support provided by Dr. Thomas Paez who has contributed his expertise in probabilistic shock and vibration analysis, and has been very helpful in providing analytical models and software used in the numerical demonstrations.


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Copyright information

© The Society for Experimental Mechanics 2014

Authors and Affiliations

  • Timothy Hasselman
    • 1
  • George Lloyd
    • 1
  • Ryan Schnalzer
    • 1
  1. 1.ACTA IncorporatedTorranceUSA

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