Development and spectral analysis of an advanced diamond shaped resetable device control law

Passive energy dissipation has advantages such as low cost, easily predictable response, and ease of implementation, which can be offset by difficulty tuning or designing the devices for optimum behaviour over a range of inputs and responses. Recent research into semi-active energy dissipations systems has highlighted their ability to customise response and provide a control input that is adaptive to the structural response without requiring excessive energy input. In some specialised cases, specific control laws have been designed that reduce displacement and structural force, while simultaneously reducing the total base-shear transmitted to the foundation from both structural column forces and damping forces. These significant advantages can be offset by the limited energy dissipation that can arise as a result of the specific device control laws and hysteresis loops used. esearch focuses on a more effective resetable device control law called the “diamond control law”, for its unique semi-actively enabled device hysteresis loop, which maximises energy dissipation while simultaneously minimising the impact on base shear forces. It achieves this affect by controlling the release of stored energy in the resetable device – smart dissipation in place of maximum or instantaneous uncontrolled release typically used in such devices. A spectral analysis shows that this new an approach enables a decrease of 30–40% for both displacement and structural force, which is equivalent to 15–20% critical viscous damping for an uncontrolled base structure. The total base shear is also decreased by 40%, which has significant potential benefits for retrofit applications. This level of displacement and base shear reductions was not available (in combination) from prior resetable device control approaches, and thus represents a significant expansion of the design space and capability for these semi-active devices.