OPTIMAL VERSUS SUBOPTIMAL TUNED MASS DAMPERS: A COMPARISON STUDY BASED ON ENERGY TRANSFER BETWEEN PRIMARY AND SECONDARY SYSTEMS

The passage of heavy traffic in bridges potentially causes damage, which can be limited by passive device configurations such as the widely used tuned mass damper (TMD).In here, we investigate the vibratory motion caused by a heavy mass sliding on a simply supported bridge deck with a TMD attached at center span.The TMD, modelled as a single-degree-of-freedom (SDOF) secondary system comprising a mass and spring, is attached to the bottom flange to act as an energy absorber of vibrations coming from the primary system (the bridge).This sub-optimal TMD without a damper is analyzed using a Lagrangian energy balance formulation to derive the governing equations of motion, followed by a time-stepping numerical solution.Results are given in terms of time histories and power spectral densities, which allows for an investigation of the transmission of vibratory energy between primary and secondary systems.These numerical simulations help gauge the performance of a number of TMD configurations with optimized material parameters, using as benchmark the sub-optimal TMD where damping is provided by the spring element only.