Publications de Changyeob Baek

The strength of surgical knots involves a critical interplay between friction and elastoplasticity

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Changyeob Baek

Knots are the weakest link in surgical sutures, serving as mechanical ligatures between filaments. Exceeding their safe operational limits can cause fatal complications. The empirical nature of present guidelines calls for a predictive understanding of the ...

AMER ASSOC ADVANCEMENT SCIENCE2023

Exploring the inner workings of the clove hitch knot

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Tomohiko Sano, Changyeob Baek

We perform a combined experimental and computational investigation of the clove hitch knot. We develop a physical model for the clove hitch by tying an elastic rod onto a rigid cylinder. In the experiments, we characterize the mechanical performance, geome ...

ELSEVIER2022

The shapes of physical trefoil knots

John Maddocks, Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Tomohiko Sano, Changyeob Baek

We perform a compare-and-contrast investigation between the equilibrium shapes of physical and ideal trefoil knots, both in closed and open configurations. Ideal knots are purely geometric abstractions for the tightest configuration tied in a perfectly fle ...

2021

Finite Element Modeling of Tight Elastic Knots

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Tomohiko Sano, Changyeob Baek

We present a methodology to simulate the mechanics of knots in elastic rods using geometrically nonlinear, full three-dimensional (3D) finite element analysis. We focus on the mechanical behavior of knots in tight configurations, for which the full 3D defo ...

2020

Rigidity of hemispherical elastic gridshells under point load indentation

Pedro Miguel Nunes Pereira de Almeida Reis, Changyeob Baek

We present results from physical and numerical experiments on the rigidity of hemispherical gridshells under point load indentation. By systematically exploring the relevant parameters of the system, we provide a scaling law for the rigidity of elastic gri ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Form finding in elastic gridshells

Pedro Miguel Nunes Pereira de Almeida Reis, Changyeob Baek

Elastic gridshells comprise an initially planar network of elastic rods that are actuated into a shell-like structure by loading their extremities. The resulting actuated form derives from the elastic buckling of the rods subjected to inextensibility. We s ...

National Academy of Sciences2018