Depth sensing indentation of linear viscoelastic–plastic solids: A simple method to determine creep compliance
✍ Scribed by Rocio Seltzer; Yiu-Wing Mai
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 364 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0013-7944
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✦ Synopsis
Viscoelastic solids may deform plastically under indentation. This leads to an overestimation of the creep compliance when the analytical solution for indentation of linear viscoelastic materials [Lu H, Wang B, Ma J, Huang G, Viswanathan H. Measurement of creep compliance of solid polymers by nanoindentation. Mech Time-Depend Mater 2003;7(3-4):189-207] is used for its determination. Using finite element analysis, in this work it is shown that the plastic and viscoelastic deformation processes occur simultaneously, even during holding of a constant indentation load. A simple procedure to separate the viscoelastic response from the plastic response is proposed, which involves spherical indentations at different loads. To illustrate the proposed method, indentation tests are conducted on a polymer, polymethylmethacrylate (PMMA), and its viscoelastic properties are determined.