A methodology for characterization of material constants for strain-locking materials

Nicholas Payne, Kishore Pochiraju

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

Several natural materials and engineered composites exhibit a strain limiting behavior. The effective tangent modulus increases by several orders of magnitude when the strain reaches a critical range. This stiffening is produced when constituents within the composite with a higher relative modulus abruptly take on a larger percentage of the applied load after specific amount of deformation. The tangent modulus increases by an order of magnitude or more, so that the bulk composite material exhibits an effective "strain locking" behavior. A typical structure of such a material is one with a flexible matrix with wavy reinforcements. The strain locking occurs when the wavy reinforcements straighten out. Recently, implicit nonlinear constitutive models have been proposed to describe such materials with strain limits. This paper presents and validates a methodology for systematically characterizing the parameters of a strain limiting implicit constitutive model from experimentally obtained stress-strain data. The proposed methodology uses an intermediate function space to find the best fit parameters of the implicit constitutive model. The proposed characterization method employs two distinct phases. The first phase entails matching the best fit coefficients of intermediate functions that represent the experimental data and material constitutive model. This provides a good initial point for refining the coefficients of the constitutive law with a direct minimization of the error between the experimental and modeled stress-strain data. The proposed method is demonstrated using an experimental data set obtained from the literature that exhibits a highly abrupt tangent modulus shift and resembles a bilinear elastic material. The resulting parameter values are shown to be at a true minimum within the parameter space.

Original languageEnglish
Title of host publication32nd Technical Conference of the American Society for Composites 2017
EditorsR. Byron Pipes, Wenbin Yu, Johnathan Goodsell
Pages2723-2734
Number of pages12
ISBN (Electronic)9781510853065
StatePublished - 2017
Event32nd Technical Conference of the American Society for Composites 2017 - West Lafayette, United States
Duration: 23 Oct 201725 Oct 2017

Publication series

Name32nd Technical Conference of the American Society for Composites 2017
Volume4

Conference

Conference32nd Technical Conference of the American Society for Composites 2017
Country/TerritoryUnited States
CityWest Lafayette
Period23/10/1725/10/17

Fingerprint

Dive into the research topics of 'A methodology for characterization of material constants for strain-locking materials'. Together they form a unique fingerprint.

Cite this