CAEE Seminar: Targeted Energy Transfer using Nonlinear Energy Sinks for the Attenuation of Transient Loads on Building Structures

The Civil, Architectural and Environmental Engineering department and Dr. Jamshid Mohammadi will be hosting a seminar featuring Nicholas E. Wierschem, Ph.D., Postdoctoral Research Associate, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign - Candidate for the position of assistant professor of CAEE (Specialty: Structures). The topic of the seminar will be Targeted Energy Transfer using Nonlinear Energy Sinks for the Attenuation of Transient Loads on Building Structures.

Abstract

Nonlinear energy sinks (NESs) have been proposed as a practical and robust means of passively protecting buildings structures subjected to extreme transient loads. NESs are a type of passive attachment that differentiate themselves from tradition linear attachments, such as TMDs, through the exploitation of essentially nonlinear stiffness elements. These essentially nonlinear elements allow the NES to interact with any mode of a primary structure and participate in targeted energy transfer, the nearly one-way transfer of energy from the primary structure to the NES where it can be rapidly dissipated. Additionally, this nonlinear restoring force allows the linear modes of the primary structure to become coupled and energy to be transferred from the lower modes of vibration to the higher modes where it is dissipated at a faster rate. Previous experimental studies on NESs have used table-top sized specimens; however, little work has been done using more moderately sized models and realistic loads. In this presentation, experimental testing and numerical simulations will be used to validate the potential for NESs to protect buildings structures subjected to extreme transient loads. As a part of this investigation, small-, medium-, and large-scale primary structures and several types of NESs were designed and fabricated. With these structures and NESs, the experimental validation was carried out using an impulse-like ground motion produced by shake tables. Additionally, large-scale validation of a system of NESs was performed with explosive blast loading and seismic loading. The results of this work show that NESs can significantly attenuate the response of building structures subjected to a variety of different transient load types, as well as reduce the peak demand on a structure. Furthermore, the synergistic effects realized by the simultaneous use of different types of NESs allows for consistent performance to be maintained across a broad range of load amplitudes.