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Local mechanical behavior mapping of a biopolymer blend using nanoindentation, finite element computation, and simplex optimization strategy
Author(s) -
Guessasma Sofiane,
Zhang Weihong,
Zhu Jihong
Publication year - 2017
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.44891
Subject(s) - nanoindentation , materials science , finite element method , modulus , composite material , tangent , plasticity , tangent modulus , stiffness , mathematics , geometry , structural engineering , engineering
In this study, we suggest a simple scheme to derive interfacial behavior using combination of nanoindentation and finite element computation. The starting point is the experimental generation of a rectangular grid composed of 32 indentations to measure the exact variation of stiffness across the interface of a bio‐based composite. A finite element simulation of nanoindentation is implemented based on elasto‐plastic material model. An optimization strategy is used to identify the behavior of all phases by matching predicted results to observed mechanical response. Results show that extent of interphase layer has a typical dimension of 8.0 ± 4.9 µm. The optimization strategy based on simplex proves to be efficient to derive the elasto‐plastic behavior of the blend across the interface with a residual value of less than 30 µN. The identification procedure demonstrates that the extent of the interfacial region depends on the measured physical quantity. The contrast across the interface for both Young's and the tangent moduli appear to be more effective than the contrast given by the yield stress. Identified Young's moduli for zein, starch, and interfacial zone are 4.78 ± 0.27, 4.13 ± 0.19, and 3.91 ± 0.17 GPa. Plasticity parameter represented by tangent modulus varies in the same order as 1238 ± 120, 847 ± 108, and 976 ± 94 MPa, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44891.