Dynamic response of tertiary subsystems

Takeru Igusa, Armen Der Kiureghian

Research output: Contribution to journalArticle


An efficient and accurate method is presented for dynamic analysis of tertiary subsystems mounted on primary-secondary systems, such as control devices attached to piping in nuclear power plants. Modal properties, such as natural frequencies, damping ratios, and mode shapes, of the composite primary-secondary-tertiary system are derived in terms of the known subsystem properties, employing previously developed modal synthesis and perturbation results for primarysecondary systems, which are extended here to subsystems with nonclassical damping. The method is direct in that the response of the tertiary subsystem is obtained in terms of the input excitation without the need to generate intermediate results, such as floor response spectra. Important effects of tuning, interaction, nonclassical damping, and spatial coupling are fully accounted for. The paper also presents an in-depth analysis of the conditions and effects of tuning in primarysecondary- tertiary systems.

Original languageEnglish (US)
Pages (from-to)1375-1395
Number of pages21
JournalJournal of Engineering Mechanics
Issue number8
Publication statusPublished - Jan 1 1988
Externally publishedYes


ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering

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