In this study, we investigate the monotonic deformational response of Polyvinylidene fluoride (PVDF). Monotonic uniaxial and biaxial experiments are conducted and deformations are monitored using non-contact speckle monitoring method. The mechanical response of PVDF is observed to exhibit finite strains which are also anisotropic in nature. A hyper-elastic finite deformation transversely isotropic model is used to model the biaxial response of PVDF. Experimental data was shown to fit well with the proposed model. The model parameters obtained from biaxial tests were used to capture uniaxial response in two orthogonal directions and the ability of the model to predict any arbitrary mechanical response is assessed. © 2017, The Society for Experimental Mechanics, Inc.

C. Lakshmana Rao

Department of Applied Mechanics

L. Harish

Anisotropy

Constitutive models

Deformation

Anisotropic

Finite deformations

HYPER ELASTIC

NONCONTACT MEASUREMENTS

PVDF

Fluorine compounds

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Experimental Techniques

In this study, we present the results of cyclic electromechanical experiments conducted on uniaxially stretched poly(vinylidene fluoride) (PVDF) films. The experiments were carried out over a range of applied displacement amplitude ranging from 0.5 mm to 1.5 mm, superposed on an initial stretch on the test samples. The strains were calculated using non-contact speckle monitoring method. The hysteresis plots of mechanical and electromechanical cyclic responses are presented. Stress relaxation was observed up to 70% in orthogonal to stretch direction and 16% in the stretch direction. Observed piezoelectricity along both the directions is reported and discussed in the paper. Copyright © 2019 Inderscience Enterprises Ltd.

Fulltext

International Journal of Materials and Structural Integrity

Cyclic electromechanical response of poly(vinylidene fluoride)

In this study, results from monotonic uniaxial and biaxial stretch experiments carried out on rectangular uniaxially stretched PVDF thin samples, is reported. Both mechanical and electromechanical response of the film is reported in the study. Non-linearity in mechanical and electromechanical response is observed. Anisotropy in mechanical and electromechanical response is also noted from uniaxial and biaxial experiments. Constitutive models that are developed to capture (a) nonlinearity and (b) anisotropy are reported both for a mechanical and electromechanical response. © 2019, © 2019 Taylor & Francis Group, LLC.

Ferroelectrics

Monotonic uniaxial and biaxial electromechanical experiments and modeling of uniaxial stretched polyvinylidene fluoride (PVDF)

Using a custom built experimental setup, biaxial and uniaxial extension tests are performed on the same specimen. In biaxial tests, the stretch ratio along y direction is held constant and the stretch ratio in the perpendicular x direction is increased gradually from 1 to 1.4. Stored energy function is obtained from seven different biaxial tests performed by varying the stretch ratio along the y direction at which it is held fixed. Stored energy functions are proposed for the tested rubber sheets by allowing the stored energy to be a function of the principal invariants of right Cauchy-Green deformation tensor or the invariants of the Hencky strain or the principal stretch ratios. To evaluate the performance of the developed stored energy functions, they are compared with 10 existing constitutive relations available in literature in terms of their ability to capture their biaxial response and predicting capability for the uniaxial experiments on the rubber specimens studied. This study reveals that the stored energy function developed in this study as a function of the principal invariants of the right Cauchy-Green deformation tensor predicts the uniaxial behavior the best and capture the biaxial response second best among the models studied for the tested material. However, even this model on an average has 25 percent error in the predicted stresses. © 2015 Elsevier Ltd. All rights reserved.

Mechanics of Materials

A new set of biaxial and uniaxial experiments on vulcanized rubber and attempts at modeling it using classical hyperelastic models

Polyaniline (PANI) an electronically conducting polymer, and its charge transfer complexes are interesting engineering materials due to their unique electronic conductivity, electrochemical behavior, low raw material cost, ease of synthesis and environmental stability in comparison with other conjugated polymers. The main disadvantage of PANI is its limited processability. Blending of conducting polymers with insulating polymers is a good choice to overcome the processability problem. In this study a solution-blend method is adopted to prepare conductive polyaniline/polyvinyl alcohol (PANI/PVA) blend films at various blend ratios. Interest in applications for polyaniline (PANI) has motivated investigators to study its electro mechanical properties, and its use in polymer composites or blends with common polymers. The work described here looks at the uniaxial deformation behavior of the conducting polymer films and the anisotropic dependency of electrical conductivity of the blend films exposed to static and dynamic loading conditions. The relation between mechanical strain, electrical conductivity and film microstructure is investigated on PANI/PVA blend films. Copyright © 2012 by ASME.

ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2012

Electromechanical behavior of conductive polyaniline/poly (Vinyl Alcohol) blend films under uniaxial loading

This paper describes the results from electromechanical tests conducted on polyvinylidene fluoride (PVDF) sheets showing its nonlinear and time-dependent electromechanical behavior. Mechanical and electromechanical tests were carried out for both uniaxially stretched and biaxially stretched PVDF sheets. The tests show nonlinearity in both the stress-strain response and the time-dependent response. Electromechanical dynamic tests were conducted at various superimposed pre-stress conditions. From the dynamical electromechanical tests, it is found that both biaxially stretched and uniaxially stretched PVDF sheets exhibit pre-stress dependence of their electromechanical coefficients. In addition, an attempt has been made to model the mechanical and the electromechanical behavior using a simple three-parameter viscoelastic solid model. The model captures the trends observed in the experiments and is recommended as a useful tool for designs using these materials. © 2006 IOP Publishing Ltd.

Smart Materials and Structures

Nonlinear and time-dependent electromechanical behavior of polyvinylidene fluoride

Journal of Elasticity

Hyperelastic Energy Densities for Soft Biological Tissues: A Review

Tactile Sensing and Displays

Tactile Display Technology

Characterization of the Monotonic Uniaxial and Biaxial Mechanical Response of Polyvinylidene Fluoride (PVDF) Films

Journal	Data powered by TypesetExperimental Techniques
Publisher	Data powered by TypesetSpringer International Publishing
ISSN	07328818
Open Access	No