Advances in Engineering Advances in Engineering features breaking research judged by Advances in Engineering advisory team to be of key importance in the Engineering field. Papers are selected from over 10,000 published each week from most peer reviewed journals.
Proc Natl Acad Sci U S A. 2014 Sep 29.
Jawed MK (1), Da F (2), Joo J (2), Grinspun E (3), Reis PM (4).
1Departments of Mechanical Engineering and.
2Department of Computer Science, Columbia University, New York, NY 10027.
3Department of Computer Science, Columbia University, New York, NY 10027 [email protected] [email protected].
4Departments of Mechanical Engineering and Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139; and [email protected] [email protected].
ABSTRACT
We investigate the deployment of a thin elastic rod onto a rigid substrate and study the resulting coiling patterns. In our approach, we combine precision model experiments, scaling analyses, and computer simulations toward developing predictive understanding of the coiling process. Both cases of deposition onto static and moving substrates are considered. We construct phase diagrams for the possible coiling patterns and characterize them as a function of the geometric and material properties of the rod, as well as the height and relative speeds of deployment. The modes selected and their characteristic length scales are found to arise from a complex interplay between gravitational, bending, and twisting energies of the rod, coupled to the geometric nonlinearities intrinsic to the large deformations. We give particular emphasis to the first sinusoidal mode of instability, which we find to be consistent with a Hopf bifurcation, and analyze the meandering wavelength and amplitude. Throughout, we systematically vary natural curvature of the rod as a control parameter, which has a qualitative and quantitative effect on the pattern formation, above a critical value that we determine. The universality conferred by the prominent role of geometry in the deformation modes of the rod suggests using the gained understanding as design guidelines, in the original applications that motivated the study.
Significance Statement
The researchers predicted the pattern of coils and tangles that a cable may form when deployed onto a rigid surface. This will improve our understanding of improved telecommunications especially in undersea fiber-optic network.
