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Response of secondary systems in structures subjected to transient excitation
Author(s) -
Hernried Alan G.,
Sackman Jerome L.
Publication year - 1984
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290120603
Subject(s) - modal , modal analysis , natural frequency , transient (computer programming) , structural engineering , perturbation (astronomy) , matrix (chemical analysis) , newmark beta method , excitation , engineering , mathematical analysis , finite element method , control theory (sociology) , mathematics , computer science , physics , acoustics , vibration , materials science , control (management) , composite material , quantum mechanics , chemistry , electrical engineering , artificial intelligence , polymer chemistry , operating system
An analytical method, based on matrix perturbation theory, is developed whereby a simple estimate can be obtained of the maximum dynamic response of lightly damped, light equipment (modelled as a n ( 2 )‐degree‐of‐freedom system) attached to a structure (modelled as a n ( 1 )‐degree‐of‐freedom system) subjected to ground motion or impact. A natural frequency of the equipment is considered close or equal to a natural frequency of the structure. It is assumed that the information available to the designer is a time history of the ground motion or impact, or an associated design spectrum; the fixed base modal properties of the structure; and the fixed base modal properties of the equipment. The method employed avoids the direct conventional analysis of a n ( 2 ) + n ( 1 )‐degree‐of‐freedom system either by modal or by matrix time‐marching methods; as well as errors in estimates of peak response due to the possible unreliability of numerical schemes because of the lightness of the equipment, or due to uncertainty as to the appropriate procedure for summing the contributions of the two closely spaced modes which occur in the system. The proposed procedure is demonstrated for an example equipment‐structure system. Computed results based on the method are in close agreement with results obtained through a Newmark time‐integration scheme.