Extreme power amplification in biological systems


Meeting Abstract

16-6  Thursday, Jan. 5 11:15 – 11:30  Extreme power amplification in biological systems PATEK, S.N.*; AZIZI, M.; BHAMLA, M.S.; COX, S.; ILTON, M.; KIM, Y.; KOH, J.; KUO, J.; MA, X.; PRAKASH, M.; SUTTON, G.P.; TEMEL, Z.; Duke U.; U. CA Irvine; Stanford U.; Penn State U.; UMass Amherst; UMass Amherst; Harvard U.; Duke U.; U. MD College Park; Stanford U.; U. Bristol; Harvard U. snp2@duke.edu http://www.thepateklab.org

The extraordinary accelerations of jellyfish stingers, trap-jaw ant mandibles and mantis shrimp hammers occupy a notable region of extreme mechanical power amplification that yields intense and transient forces directed to the external environment. Systems capable of extreme power amplification share three core components – motors, springs and latches. We have used simple mathematical simulations and a broad comparative dataset to explore the shared features and constraints of these systems. We found that springs are most beneficial when the take-off velocity of a projectile is limited by motor velocity and are not particularly effective when take-off velocity is limited by projectile inertia. Springs are typically tested at low rates and without realistic loading; however, in extreme power-amplified systems, springs actuate the movement and do so at extremely high rates. We found that the loading and rate dependence of hypothetical elastic mechanisms influence power output and velocity. Latches enable power-amplified systems to enhance potential energy storage while separating and controlling the transition from potential to kinetic energy. We found that the mechanical behavior and associated morphology of latches mediate the spring’s actuation and the kinematic output of the system. Extreme power amplification offers a window into the costs and consequences of the temporal and spatial separation of motors, springs and latches, while informing how their integration has yielded a remarkable biological diversity of extreme kinematic performance.

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