Masses of Normal Modes for Structures with Multiple Supports

摘要

The Navy's dynamic design-analysis method gives shock response of equipment as a function of the frequencies and masses of its normal modes of vibration. The report shows how the definition of modal mass can be extended to the case in which different shocks are applied to the several supports for an item. Two examples for items that were subjected to impacts by torpedoes show that the extended definition reduces the predicted severity of shock response.