Session: 17-01-01: Research Posters

Paper Number: 150784

150784 - Viscoelastic and Tribological Responses of Ballistic Mechanical Metasurfaces 

High-velocity airborne particles, such as ice and sand, pose a significant threat to critical aircraft components like jet engine turbine blades, causing erosion damage. This erosion phenomenon could be a major contributor to performance degradation and maintenance costs in the aerospace industry Rationally designed micro-structured smart surfaces offer potential solutions for mitigating this damage. These structured surfaces hold promise for further functionalization, self-healing, sacrificial protection, or hydrophobicity to enhance their effectiveness in protecting critical components. While functional microscopic textures in soft materials have demonstrated remarkable adhesion and frictional properties, their behaviors under high-velocity impacts remain largely unexplored, which hinders the development of microstructured surfaces for practical applications in high-speed impact protection.Inspired by the exceptional material properties observed in microstructured biological surfaces, such as those found on gecko feet and lotus leaves, this study extends the investigation of microstructured surfaces to the high-velocity regime. It aims to elucidate their tribological characteristics and potential application in high-speed impact protection for critical components.

This work presents the ultrahigh-rate mechanical characterization of systematically designed elastomeric lattices to understand better the viscoelastic and tribological responses exhibited by the microstructured metasurfaces under high-velocity loading conditions and the underlying mechanisms. These viscoelastic metasurfaces consist of a periodic array of polydimethylsiloxane rods or micropillars microfabricated on a silicon substrate. The structural configuration of the structural elements is defined by controlling three geometrical parameters: pitch (inter-pillar distance) and pillar height and width. High-velocity impacts are conducted using the well-established laser-induced projectile impact test (LIPIT) technique. This LIPIT study employs crosslinked polystyrene microspheres as standard microparticles with an average diameter of 180 μm. The impact velocities are systematically varied across a range of 40 - 220 m/s to investigate the response of the metasurfaces under diverse loading conditions. The impact angles are set at 90° and 45° to explore the influence of mechanical symmetry breaking on the metasurfaces’ transient rheological and tribological behaviors. Following impact data acquisition, critical parameters, such as the coefficient of restitution, specific energy absorption, deflected angle, and coefficient of friction, are calculated as a function of collision velocities to quantify the structure’s ability to manipulate the rebound and energy dissipation characteristics. The metasurfaces achieve tunable synthetic viscoelastic and tribological properties by manipulating the structural parameters. Furthermore, by interpreting the acquired data as mechanical spectra conveying energy-dispersive properties of the mechanical metasurfaces, this approach potentially extends the concept of spectroscopy to the realm of mechanics.

* This research was supported by the National Science Foundation (CMMI 2318110).

Presenting Author: Zongling Ren University of Massachusetts Amherst

Presenting Author Biography: Zongling(Abigail) Ren
Ph.D. candidate in Mechanical Engineering
University of Massachusetts Amherst

Authors:

Zongling Ren University of Massachusetts Amherst
Junce Cheng University of Massachusetts Amherst
Tingyi "Leo" Liu University of Massachusetts Amherst
Jae-Hwang Lee University of Massachusetts Amherst