Modal characterization of equipment-continuous structure systems

Dynamic properties of a combined linear system composed of a single-degree-of-freedom equipment item attached to a continuous system is obtained by using the appropriate Rayleigh quotient functional. For light equipment, closed from expressions are derived for the appropriate natural frequencies, modal functions, and modal dampings of the combined system in terms of the dynamic properties of the continuous system alone and the equipment alone. These properties can be used in conjunction with any suitable dynamic analysis procedure based on the mode-superposition method. For an example structure, computed natural frequencies and modal functions based on the proposed method are in close agreement with exact results.