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Axial compression of
hollow elastic spheres
Robert Shorter, John D. Smith, Vincent A. Coveney and James J. C. Busfield |
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Vol. 5 (2010), No. 5, 693–705
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Abstract |
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When thin-walled hollow elastic spheres are compressed between two parallel rigid surfaces, there is an initial flattening of the sphere in the contact regions, followed by a snap-through buckling of the flattened surface. As the compression increases the sphere undergoes further buckling modes as a number of ridges and folds are formed. This elastic buckling deformation is investigated using a finite element analysis (FEA) technique. It is shown that the ratio of displacement at buckling to wall thickness depends weakly not only on Poisson’s ratio, , but also on the ratio of the geometric wall thickness, , to sphere radius, . This approach is validated by comparison with experimental compression results on microspheres of approximately 40 m in diameter to table tennis balls with a diameter of 40 mm. The analysis shows that a simple axial compression of a thin-walled hollow sphere can be used to measure both the average wall thickness of the sphere, from the deformation at the buckling snap-through, and the modulus from the force at this point. This provides a good technique to fully characterise the geometry and the elastic behaviour of thin-walled spheres of any size. |
Keywords
compression, buckling, instability, hollow spheres, finite
element analysis
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Milestones
Received: 17 October 2008
Revised: 15 June 2010
Accepted: 8 July 2010
Published: 3 December 2010
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Authors |
| Robert Shorter | |
| Department of Materials Queen Mary University of London Mile End Road London E1 4NS United Kingdom |
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| John D. Smith | |
| Defence Science and Technology
Laboratory Porton Down SP4 0JQ United Kingdom |
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| Vincent A. Coveney | |
| Engineering and Medical Technology
Research Centre University of the West of England Bristol BS16 1QY United Kingdom |
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| James J. C. Busfield | |
| Department of Materials Queen Mary University of London Mile End Road London E1 4NS United Kingdom |
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