Computational and experimental study of instrumented indentation

The effect of characteristic length scales, through dimensional and microstructural miniaturizations, on mechanical properties is systematically investigated by recourse to instrumented micro- and/or nanoindentation. This technique is capable of extracting mechanical properties accurately down to nanometers, via rigorous interpretation of indentation response. Such interpretation requires fundamental understandings of contact mechanics and underlying deformation mechanisms. Analytical, computational and experimental approaches are utilized to elucidate specifically how empirical constitutive relation can be estimated from the complex multiaxial stress state induced by indentation. Analytical formulations form a framework for parametric finite element analysis. The algorithms are established to predict indentation response from a constitutive relation (hereafter referred to as "forward algorithms") and to extract mechanical properties from indentation curve (hereafter referred to as "reverse algorithms"). Experimental verifications and comprehensive sensitivity analysis are conducted. Similar approaches are undertaken to extend the forward/reverse algorithms to indentations using two ore more tip geometries. Microstructural miniaturization leads to novel class of materials with a grain size smaller than 100 nm, hereafter referred to as "nanocrystalline" material. Its mechanical properties are observed to deviate greatly from the microcrystalline counterparts.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Chollacoop, Nuwong, 1977-

Advisor dc:contributor.advisor

• Subra Suresh.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/16624

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/16624