SMI - A structural dynamics toolbox for integrated modeling

M. Müller, H. Baier

Research output: Contribution to journalConference articlepeer-review

9 Scopus citations


In cooperation with the European Southern Observatory (ESO), the Institute of Lightweight Structures (LLB), Technische Universität München, has developed the Structural Modeling Interface Toolbox (SMI), a Matlab based software package for creation of a dynamical model of a telescope structure. It is called Interface, since it uses the modal data of a finite element (FE) analysis and creates a dynamic model to be used within a time-dependent control loop simulation in the Matlab/Simulink environment. SMI is part of the Integrated Modeling Toolbox (IMT) developed in a joint effort by ESO, Astrium GmbH and LLB. Since SMI can read modal data in a general format, it is not depending on the FE-software. In addition to that, an interface to the FE-package ANSYS has been developed. It allows the variation of parameters and some settings for the FE-analysis directly within SMI. Both, force excitation like windloads and base excitation like micro seismic perturbations can be included. Several tools for model reduction are provided. Some of them are modal based, like effective modal masses, others are general model reduction procedures from control engineering like balanced truncation. For the evaluation of the reduced models, transfer functions of different models can be displayed in a Bodeplot. Time characteristics like step response or impulse response are also available. Moreover, for a typical excitation PSD the response PSD can be computed. This response can either be compared to the response of an exact model or to measured data and the rms-error can be calculated. The final result is a linear statespace model of the structure and a Simulink block, which can be included into a Simulink model.

Original languageEnglish
Pages (from-to)41-50
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2002
EventWorkshop On Integrated Modeling of Telescopes - Lund, Sweden
Duration: 5 Feb 20027 Feb 2002


  • Finite element modeling
  • Integrated modeling
  • Model reduction
  • Telescope structures
  • VLTI
  • Wind


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