Mode localization in structures consisting of substructures and couplers

The influences of the coupler consisting of stiffness and mass and connecting two neighboring substructures on mode localization are studied theoretically, and the results are confirmed by numerical examples. The mass of the coupler makes a structure sensitive to mode localization especially in higher modes while the stiffness does in all modes. A new type of delocalization phenomenon is observed for the first time in some modes, for which mode localization does not occur or is very weak although structural disturbances are severe. A spring-mass system consisting of two substructures and a coupler connecting them is considered in the part of analytical study. As example structures for numerical analysis, simply supported continuous two- and three-span beams with couplers having a rotational stiffness and a rotational mass are considered.