Session: SYMP 5-3: SHM for Extreme Load Applications

Paper Number: 141081

141081 - Peridynamic Approach to Hypervelocity Impact Detection on Lunar Structures 

Lunar infrastructure including future human habitats need resilient design to withstand the moon's extreme environment. The lack of an atmosphere implies that lunar structures shall experience varying degrees of damage due to micrometeoroid impacts. Due to their hypervelocity, averaging at nearly 20 km/s, even micrometeoroids that are only a few hundred microns in size can cause significant damage. It is imperative to detect and quantify this damage for operational safety and order necessary repairs. The motivation for this research is to expand beyond sensor-based system level impact detection, into damage detection using a multifunctional composite material comprised of lunar regolith, polymer binder and carbon nanotubes (CNT). The piezoresistive response of these CNT infused nanocomposites can be monitored for strain and damage sensing. A critical concern for the development of such multifunctional composites is the challenge of understanding and predicting the nonlinear dynamics relating to hypervelocity impacts (> 1 km/s). Physically accelerating projectiles to hyper velocities for experimental studies is exceedingly challenging and expensive, while traditional numerical methods struggle with simulating the complex, discontinuous damage patterns associated with impact dynamics. In recent times, peridynamics, which is an integral based non-local continuum formulation, has been established as an ideal tool for modeling discontinuities. This work accomplishes preliminary characterization of CNT based multifunctional lunar composites via numerical simulations performed using a coupled thermo-electromechanical, bond-based peridynamic approach. A macroscale material model with homogenized effective properties for the target is adopted. Three primary goals are addressed: (1) Detection of damage occurrence (2) Identification of damage location (3) Quantification of damage extent. Several numerical simulations are carried out spanning a range of projectile impact velocities from 2 km⁄s to 20  km⁄s for micrometeoroid diameters ranging from 500 microns-2 mm. Comparative analysis of mechanical deformations and crater profiles is presented with respect to finite element analyses. The effects of impact angles (increments of 15 degrees up to 90 degrees) on damage detection are studied by measuring the material’s piezoresistive response for various cases. Results are presented for various material compositions to enable optimal design of a regolith based multifunctional lunar composite. This research not only advances capabilities for detection of damage due to hypervelocity micrometeoroid impacts, but The peridynamic framework for hypervelocity impacts developed here also lays the groundwork for developing versatile smart multifunctional materials suitable for a variety of applications such as orbital debris impact detection on satellite components, projectile modeling in the defense sector, marine and automotive design, and smart spacesuits enabled with structural health monitoring.

Presenting Author: Bala Priya Shanmugam Virginia Tech

Presenting Author Biography: Bala Priya Shanmugam is a PhD student in Engineering Mechanics at Virginia Tech. Fundamentally an aerospace engineer, she has a multidisciplinary background with graduate degrees in mechanical, and civil engineering and several years' experience as a structural analysis engineer in the marine industry. Her current research focuses on multifunctional lunar composites with Dr. Gary Seidel's research group at Virginia Tech.

Authors:

Bala Priya Shanmugam
Gary Seidel