PASSIVE BLAST AND SEISMIC MITIGATION OF LARGE-SCALE CIVIL INFRASTRUCTURE BY IMPLEMENTATION OF INTENTIONAL STRONG NONLINEARITY

Abstract eng:
We implement intentional strong nonlinearity for targeted energy transfer - TET and passive energy management in a structural design. By nonlinear TET [1] we denote passive, nearly one-way transfer of blast energy from an excited primary system to a set of local, dissipative and essentially nonlinear (i.e., nonlinearizable) attachments (termed nonlinear energy sinks – NESs) where energy is spatially confined and locally dissipated. Although the NESs are local devices, due to their strong nonlinearity can affect the global dynamics of the primary system over broad frequency and energy ranges, acting as passive, broadband and adaptive boundary controllers, tunable with energy. Moreover, there is passive redistribution of induced energy within the modal structure of the system through directed energy exchanges between sets of linear modes or to nonlinear modes induced by the strong nonlinearity. We will discuss blast mitigation of a ninestory structure weighting 10 tons, specifically built for this series of blast tests. A passive mitigation system of six NESs is deployed on the upper two floors of the structure; two NESs have vibro-impact nonlinearities, and the other four have smooth but essentially nonlinear stiffnesses (see Figure 1). Experimental tests proove the capacity of this passive nonlinear mitigation system to rapidly and efficiently attenuate the structural response, even starting at the first response cycle, thus minimizing the peak demand on the structure. This is achieved by nonlinear redisribution of the blast energy within the modal space through low-to-high energy scattering caused by the actions of the NESs. The experimental blast tests will be discussed [2]. This application highlights the unique and unprecedented options for design that the use of intentional strong nonlinearities can offer.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket