Stress Wave Propagation and Tunability in 1D Granular Systems
Abstract
Mechanical stress wave propagation in granular materials has attracted much attention for exploring new physical phenomena due to versatile engineering applications. One-dimensional (1D) granular systems, a type of artificially designed granular materials consisting of periodically aligned discrete particles, are demonstrated to produce unprecedented wave properties that are notably different from conventional engineering materials. By designing the critical characteristics of 1D granular systems, a remarkable tunability can be achieved, which yields various engineering applications. However, a systematic understanding of the stress wave behaviors within the system is still lacking. Therefore, in this dissertation, firstly, 1D cylindrical composite granular chains are systematically investigated via experiments, numerical simulations, and theoretical analysis, which is demonstrated to support strongly nonlinear solitary waves. By creating material mismatch within single granular particles, a shell-dominated dynamic response is achieved in 1D composite granular chains. Next, the dynamic properties of solitary waves supported by 1D spherical granular chains are analyzed, making it possible to achieve an equivalent wave transmission among various materials and dimensions. Accordingly, two types of equivalent systems are designed to expand the understanding of governing factors in wave dynamics, including generalized and restricted equivalent systems. Furthermore, two types of highly efficient and controllable stress wave attenuation approaches are developed based on 1D hollow cylindrical particles and kirigami lantern structures. The fundamental mechanisms of the two strategies are strain-softening behaviors of hollow cylindrical particles and unique folding-unfolding responses of kirigami cells during stress wave propagation, respectively. Finally, 1D cylindrical granular systems with various mismatch configurations, including mass, modulus, and thickness mismatch, are tailored to investigate quantitatively solitary wave tuning strategies. Meanwhile, the solitary wave attenuation capability can be further boosted by coupling different strategies or creating a multilayer granular chain. This study comprehensively explores the stress wave propagation and tunability in various 1D granular systems via an integrated methodology, systematically uncovering the fundamental physical relations between wave dynamics and system properties. Results promote the science of stress wave propagation by developing the fundamental stress wave propagation laws and provide design guidance for next-generation impact protection, signal measurement, and monitoring systems.