Sandia National Laboratories / NOMAD Research Institute
Summer 2025 internship work on a watch-like ratcheting mechanism, focused on separating physical response from sensitivity introduced by finite-element setup choices. NOMAD stands for Nonlinear Mechanics and Dynamics Research Institute; Alan's internship ran June 16-August 8 in Albuquerque through Sandia National Laboratories and the University of New Mexico, with the final NOMAD presentation delivered August 5, 2025. The public record includes the IMAC-accepted coauthored paper, final NOMAD presentation, Alan's Soft Robotics Lab presentation, completed results matrix, and mechanism/FEA media extracted from the final deck.
Multibody animation loops show the ratcheting assembly and the contact-rich motion that motivated the submodel sensitivity study.
The pawl gear assembly was divided into pin-spring-pawl, pin-pawl, and pawl-gear submodels. Each was tested under Haversine shock and sinusoidal vibration while varying momentum-balance iteration, mesh density, and processor count.
Complete convergence between runs for the momentum-balance, mesh-density, and processor-count sweeps. The Haversine cases showed that one momentum-balance iteration was noisier but still tracked the trend; the sinusoidal cases converged while the idealized model underpredicted force.
Rotation and contact force became erratic after contact/friction dominated. Very coarse mesh cases produced lock-up behavior, and sinusoidal vibration amplified divergence relative to the Haversine shock cases.
Momentum-balance iteration and mesh density remained sensitive. Processor-count variation was the one Pawl-gear parameter class marked convergent in the completed results summary.
Quantifying the Effect of Non-Physical Parameters on the Nonlinear Dynamics of an Electromechanical Ratcheting Mechanism.
Final internship presentation delivered August 5, 2025. The PDF is hosted directly; the 214 MB PPTX is hosted as a release asset.
Alan's lab presentation summarizing the internship setting, application process, NOMAD structure, and research connection to soft robotics and compliant mechanisms.
