This dissertation work is focused on the analytical and numerical examination of
the mechanical response of polypropylene (PP) under scratch deformation by a semispherical
indenter. The finite element (FE) method is employed as the analysis
technique and ABAQUS??, a commercial FE package is adopted to perform the analysis.
Important physical and computational considerations on the implementation of FE
analyses for the scratch problem are reviewed. It is shown through the discussion of the
generated results that a good understanding can be gained on how different scratch
conditions can affect scratch behavior of PP. A phenomenological deduction of the
scratch damage process and mechanisms is also established. Considering the two main
damage modes of polymers, shear yielding and crazing, it is shown that the two damage
modes not only exist in the scratch deformation, and moreover, that they may compete
against each other for dominance. A parametric study is also performed to assess the
influence of material and surface properties on scratch response of material.
A secondary research effort is also made to investigate the material constitutive
modeling of polymers. Focusing on elastomeric or rubbery materials, a new mixed network model between the Gaussian and eight-chain non-Gaussian models is proposed.
This mixed model inherently preserves the good predictive power of these two models
and yields better predictions over a wider range of deformation than that of the rubber
model adopted by ABAQUS??.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/2720 |
| Date | 01 November 2005 |
| Creators | Lim, Goy Teck |
| Contributors | Reddy, J. N. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 1901831 bytes, electronic, application/pdf, born digital |
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