A Positive Effect of Negative Stiffness: Wave Behavior and Energy Management

Michigan State University, East Lansing MI

Investigators

Abstract

The objective of this research is to analyze and then utilize the dynamic behavior that results from incorporating components with negative stiffness into electro-mechanical and structural systems. The research focuses on such phenomena as band-gaps, twinkling, bi-stability, signal magnification and frequency induced softening, towards applications such as energy dissipation and absorption, energy transfer, energy harvesting, waveguides and vibration absorbers. Research issues include understanding of the nonlinear transient dynamics between expanded and contracted snap-through states, analysis and design of high-frequency dynamics that result from low frequency inputs, derivation of effective dynamical properties for assemblies of small scale units of negative stiffness, development of topology optimization methods to handle systems with negative stiffness, innovative usage of objective functions for design of desired behavior, construction of experiments using magneto-elastic base structures, and the measurement and characterization of dynamic responses in experiments. The research will be conducted using a combination of physical experimentation and rigorous analytical techniques, such as Bloch-Floquet theory and topology optimization. This research supports and leads to the creation of new tools that facilitate the development of novel and more effective engineered materials. The work explores the concept of elements of negative stiffness and their incorporation in assemblies that have dynamic properties that do not occur in standard materials. The advanced devices that become possible through the use of these materials are likely to generate growth in a number of high-technology industries: medical diagnostic equipment, sensing devices for non-destructive testing, automotive, environmental (sound abatement), and energy harvesting. The research seeks an enhanced understanding of a variety of phenomena of relevance in emerging technologies: wave propagation in periodic media, acoustic and vibration energy management, metamaterial design in the acoustic and ultrasonic range. The work also provides a framework for the understanding of the effect of negative stiffness in different physical domains and develops new insights into the design of systems that take advantage of this fresh understanding.