Estimation of the equivalent complex modulus of laminated glass beams and its application to sound transmission loss prediction

The complex modulus E(jω) characterizes the visco-elastic behavior of a material. Using a system identification approach, this modulus can be measured via broadband modal analysis experiments. The technique is applied to determine the equivalent complex modulus E(jω), with its uncertainty bound, of multilayer glass beams from transversal vibration experiments in free-free boundary conditions. This property is related to the effective complex bending stiffness of the laminated glass specimen, and is further used for predicting the sound transmission loss of a multilayer plate. The data are rationalized in the terms of the linear visco-elastic properties of the polymer interlayer.