Next Generation Structural Technologies : Implementing High Force-To-Volume Energy Absorbers
Thesis DisciplineMechanical Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
This thesis explores the design development, experimental testing, and structural implementation of high force-to-volume (HF2V) damping devices. The development of damage-free structural design methods requires an alternate means of dissipating energy, as eliminating structural damage eliminates the primary energy dissipation mechanism. The HF2V devices developed within this thesis provide a damage-free energy dissipation mechanism and can be used in structures subjected to earthquake excitation. The devices developed are much smaller, more compact versions of lead extrusion dampers previously utilised for structural applications such as base-isolation. The devices provide the same force levels in a significantly smaller package, greatly extending the possible applications. Therefore, the development of these devices is a significant step towards developing damage-free structural design methods and reducing the impact of seismic events on a society.
The results indicate that the HF2V devices provide repeatable, consistent energy dissipation on repeated cycles, without any stiffness or strength degradation, and without any requirements for repair or replacement following an earthquake. This outcome is unique to these devices, and these characteristics are not available with the alternatives typically used within this field, such as yielding steel fuse-bars or proprietary viscous dampers. These devices therefore provide a unique opportunity to provide large energy dissipation in a very compact package that can easily be incorporated into a structural connection. At $100-300 each the devices cost several orders of magnitude less than proprietary viscous dampers and are much smaller physically, but provide equivalent or greater force capacity, making them an economically and technologically feasible option.
The devices are implemented into three structural systems, with numerous configurations tested for each structural system to provide alternate methodologies and delineate the contributions to response. The structural implementations show significant promise and highlight several key design recommendations to optimise their use. Finally, analytical models of varying complexity of the device and connection response are developed. The simple models are intended as an initial design tool, with the more detailed models developed as evaluation tools for initial designs. These models provide the tools to incorporate these devices into design practices and create a bridge to the profession.
Overall, this thesis develops high force-to-volume damping devices from an initial concept, through prototype development, to structural implementation and associated modelling. The key design issues are identified and significant progress is made towards this design approach receiving uptake by the profession.