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On the indentation contact area of a creeping solid during constant-strain-rate loading by a sharp indenter

Published online by Cambridge University Press:  03 March 2011

Naoki Fujisawa  and
Michael V. Swain
Naoki Fujisawa*
Affiliation:
School of Aerospace, Mechanical & Mechatronic Engineering, University of Sydney, Sydney, NSW 2006, Australia
Michael V. Swain
Affiliation:
Biomaterials Unit, Department of Oral Sciences, School of Dentistry, University of Otago, Dunedin, New Zealand; Biomaterials Science Research Unit, Faculty of Dentistry, University of Sydney, United Dental Hospital, Surry Hills, NSW 2010, Australia; and School of Aerospace, Mechanical & Mechatronic Engineering, University of Sydney, Sydney, NSW 2006, Australia
*
a) Address all correspondence to this author. e-mail: naoki.fujisawa@anu.edu.au
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Abstract

Poly(methyl methacrylate) was contacted by a Berkovich indenter at a range of constant loading strain rates. This particular loading scheme was used to maintain the strain-rate-dependent elastic modulus and indentation hardness of the creeping solid constant throughout loading. A loading curve analysis method identical to that of Malzbender and de With but based on the elastic-perfectly plastic contact model of Hochstetter et al. [Tribol. Int.36, 973–985, 2003] was used to process the load-displacement curves. Using the analysis method together with the strain-rate-dependent elastic modulus of the creeping solid known a priori, the strain-rate-dependent hardness could then be predicted. The predicted hardness versus strain-rate relationship was compared with that evaluated from the observed topographic images of the residual impressions due to heavier indentations at three constant loading strain rates. Based on this comparison, the elastic-perfectly plastic contact model was shown to be applicable to the creeping solid only when deformation takes place at a quasi-static strain rate.

Keywords

Elastic propertiesHardnessPolymer
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 4 , April 2007 , pp. 893 - 899
Copyright
Copyright © Materials Research Society 2007

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References

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