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Energy dissipation

Ramathasan Thevamaran's picture

Mitigating Oblique Impacts by Unraveling of Buckled Carbon Nanotubes in Helmet Liners

Abstract

 

Background: Helmet systems most commonly experience oblique blunt impacts which cause simultaneous linear and rotational accelerations. The ability to attenuate both linear and rotational accelerations by absorbing the normal shock while accommodating large shear deformations with energy dissipation is critical to developing superior helmet liners that prevent traumatic brain injury (TBI).

 

Does anyone know how ABAQUS calculate ALLCD (viscoelastic energy dissipation)

Hi, 

I am doing some study with viscoelastic energy dissipation. I have a basic question for ABAQUS. 

In ABAQUS, I notice there is a function to calculate Energy dissipated by creep, swelling, and viscoelasticity (ALLCD). You are able to plot energy change with time. 

But want to know how ABAQUS calculates energy dissipation with time? What equation does it use?

Controllable viscoelastic behavior of vertically aligned carbon nanotube arrays

Controllable viscoelastic behavior of vertically aligned carbon nanotube arrays

 

Kilho Eom, Kihwan Nam, Huihun Jung, Pilhan Kim, Michael S. Strano, Jae-Hee Han, Taeyun Kwon

 

Abstract

Xiaoyan Li's picture

Simulating Fullerene Ball Bearings of Ultra-low Friction

We report the direct molecular dynamics simulations for molecular ball bearings composed of fullerene molecules (C60 and C20) and multi-walled carbon nanotubes. The comparison of friction levels indicates that fullerene ball bearings have extremely low friction (with minimal frictional forces of  5.283×10-7 nN/atom and  6.768×10-7 nN/atom  for C60 and C20 bearings) and energy dissipation (lowest dissipation per cycle of  0.013 meV/atom  and  0.016 meV/atom  for C60 and C20 bearings). A single fullerene inside the ball bearings exhibits various motion statuses of mixed translation and rotation. The influences of the shaft's distortion on the long-ranged potential energy and normal force are discussed. The phonic dissipation mechanism leads to a non-monotonic function between the friction and the load rate for the molecular bearings.

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