Assessing impact mitigation in heterogeneous ordered granular systems

• New metrics for analyzing wave propagation in granular metamaterials. • Enhanced pulse attenuation achieved through heterogeneous granular chain configurations. • Superior wave control with Y-shaped chains’ size and material diversity. • Impact mitigation boosted by combining particle heterogeneity and structural discontinuity. The efficacy of heterogeneous granular chain configurations-decorated, stepped, and tapered Y-shaped chains-is examined for pulse wave attenuation. Variations in particle size, material properties (density and stiffness), striker velocity, and bifurcation angle are analysed to assess their influence on wave amplitude and speed. Numerical simulations and analytical models indicate that particle heterogeneity and structural discontinuities, such as chain bifurcation, significantly enhance wave mitigation. Two novel metrics, the Contact Impedance Ratio and System Impedance Product, are introduced to quantify and compare heterogeneity, demonstrating their utility in distinguishing performance benefits over monodispersed chains. These findings highlight the potential of granular metamaterials for advanced wave modulation applications and provide a basis for further studies in heterogeneous granular dynamics.