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Title: An investigation into the dynamic response of cardboard honeycombs
Author: Reay, Jonathan
ISNI:       0000 0004 5356 757X
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2014
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Cardboard honeycombs are used extensively in the packaging industry to protect objects from abnormally high loading conditions. They provide a substantial amount of energy dissipation while being lightweight, structurally efficient, cost-effective and easily disposed of (or recycled) once used. These beneficial properties have also led to the widespread use of cardboard honeycombs as a method to protect air-dropped cargo from the shock loading encountered during parachute deployment and impact with the ground. When cardboard honeycombs are crushed at the strain-rates typical of a lowvelocity impact event, such as an air drop, the air pressures, which develop within the honeycomb as a result of a compaction of the entrapped air, are comparable in magnitude to the stiffness of the cell wall deformation response. Thus, the dynamic energy dissipation properties of cardboard honeycombs are dependent on the mechanics of a coupled air-structure deformation mechanism. This thesis studies the mechanics of the air-structure deformation mechanism and investigates how it is affected by variations in the material and geometrical properties of the cardboard honeycomb cell walls. During a series of experimental impact tests on cardboard honeycomb samples of various known geometries, both macroscopic behaviour and the development of air pressures at four internal locations are measured (Chapter 3). An explicit Lagrangian/ ALE numerical model of the cardboard honeycomb and entrapped air is then developed, using the commercial hydrocode LS-Dyna (Chapter 4). The numerical model is used to study the effects of variations in the cell wall material properties (Chapter 5), and their meso and macroscale geometrical arrangement (Chapter 6) on the cardboard honeycomb's energy dissipating characteristics. A summary of the experimental and numerical findings is then given (Chapter 7), with consideration of implications for an end user.
Supervisor: Bennett, T. ; Tyas, A. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available