Thesis title: Advanced Dynamic Modeling of Multi-Storey Structures Controlled by Hysteretic Tuned Mass Dampers (HTMD) Model Updating, Experimental Validation via Distributed Sensor Networks.
This dissertation aims to provide a thorough examination of the sophisticated dynamic modelling of structures equipped with Hysteretic Tuned Mass Dampers (HTMDs) for vibration mitigation. The employed approach combines rigorous model updating, experimental validation using distributed sensor networks, and high-fidelity computational simulations. This study systematically integrates numerical modelling with empirical structural behaviour to address the fundamental challenge of reducing structural vibrations generated by seismic and dynamic loads.
The experimental framework is based on a modular prototype of a five-storey building, fabricated from high-strength carbon steel whose model has been implemented in OpenSees. A comprehensive testing protocol, including complete modal analysis, forced dynamic excitation, and free vibration tests, enables the derivation of critical structural characteristics. A precision sensor network, consisting of a PCB 086D20 modal hammer for controlled impact testing and high-resolution ICP accelerometers (Model 352C34 and Model 393A03 from PCB Piezotronics), facilitates accurate system identification and enhancement of numerical models. Dominant modal forms are retrieved from recorded data using Frequency Domain Decomposition (FDD) and Fast Fourier Transform (FFT), while a Differential Evolution (DE) optimisation approach is utilised for parameter calibration and model updating.
Two unique HTMD configurations—an Essential Stiffness TMD with bumpers and a Pinched Hysteretic TMD—are experimentally tested to examine their nonlinear responses and energy dissipation. These devices utilise restoring forces from steel wire rope and a double-sliding clamping mechanism to attain pinching hysteresis, circumventing the intricacies associated with more costly, hybrid wire ropes made of steel and shape memory alloy wires. An innovative adaptation of the Bouc-Wen hysteretic model is employed to precisely represent the force-displacement behaviour of the dampers, utilising the Differential Evolution technique for optimal parameter calibration in predictive simulations.
The feasibility of HTMDs for seismic mitigation is evaluated by applying the validated numerical model of the nonlinear damper to a large-scale electric transmission tower. The slender, lightweight lattice structure is represented using mass-loaded cable elements to replicate the dynamic coupling effects of transmission lines under severe loading circumstances. A wireless sensor network (WSN) is devised to monitor the tower's dynamic response, enabling real-time data collection and structural health evaluation. The WSN is made up of MEMS-based accelerometers that are placed strategically on an ad hoc topology of sensor nodes. The sensor network improves the accuracy of identifying modes and analysing vibrations. Comparative evaluations demonstrate that hysteretic damping techniques substantially improve energy dissipation with reduction both in resonance amplification and fatigue-related degradation. The implications of TMD frequency tuning and nonlinear hysteretic features are clarified by parametric investigations, which also emphasise the adaptability of HTMDs for large-scale, flexible infrastructural applications.
This dissertation enhances the field of structural dynamics and seismic control by integrating experimental validation with high-fidelity computational modelling. The results establish a strong basis for the adoption of hysteretic damping systems in both new and existing structures, presenting an effective, passive vibration reduction approach that improves the resilience of civil infrastructure against seismic hazards.