Study on the Influence of Impact in Tuned Mass Systems

This work evaluates how the dynamic response of the tuned mass damper (TMD) systems changes following the insertion of suitable displacement limiters. The systems, pounding tuned mass damper (PTMD), use the tuned mass to absorb the kinetic energy from the main system and dissipate it through the TMD damper and the impacts with the bumpers. Through numerical analyses, an optimal bumper design procedure is introduced; the effectiveness of the PTMD systems subjected to harmonic excitations at the base is evaluated, both for conventional and unconventional mass ratios; it is evaluated under which conditions the PTMD systems are more effective than the TMD systems; finally, the robustness of these systems to both TMD and bumpers parameters is investigated. The main results obtained have shown that (i) inserting bumpers to an optimally designed TMD does not lead to a more effective mitigation system; (ii) in those cases where optimally realizing a TMD can be complicated, or there are design constraints, the insertion of bumpers can bring significant increases in effectiveness; (iii) all the systems analyzed have shown an increase in effectiveness as the mass ratio of the TMD increases, up to a critical mass ratio after which losses in effectiveness are recorded; (iv) the analyses on the robustness of the PTMD systems have shown that such systems have good robustness both to TMD and bumpers parameters, highlighting how the parameter to which such systems are most sensitive are the distance between the auxiliary mass of the TMD and the bumpers.