FREE AND FORCED RESPONSE OF MULTISPAN BEAMS AND MULTI-BAY TRUSSES WITH LOCALIZED MODES

The influence of several effects on mode localization in free-free mul ti-span beams is investigated. Finite element methods are used to stud y localization as a function of Timoshenko beam effects, imperfection strength, coupling strength and imperfection type. The multi-span beam study is conducted with random realizations of a 40-span free-free be am. In addition, free and forced response of free-free trusses and fra mes is investigated. Results indicate that, for the trusses and frames considered, the dynamic behavior can be approximated by continuum mod elling approaches for only the lowest few global modes. Also, for reas onable values of modal damping, localized modes play a subtle role in the overall structural response.