Characterization of the Monotonic Uniaxial and Biaxial Mechanical Response of Polyvinylidene Fluoride (PVDF) Films
TL;DR: In this article, a hyper-elastic finite deformation transversely isotropic model is used to model the biaxial response of polyvinylidene fluoride (PVDF).
Abstract: 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.
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TL;DR: In this article, results from monotonic uniaxial and baoxial stretch experiments carried out on rectangular uniaxonially stretched PVDF thin samples, are reported.
Abstract: 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.
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Cites background or methods from "Characterization of the Monotonic U..."
...Harish and Lakshmana Rao [6] attempted to use the polynomial hyperelastic model to model the nonlinear elastic response of uniaxial PVDF by considering the anisotropic effects....
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...Assuming that the mechanical response of PVDF is a transversely isotropic, a polynomial strain energy function (W1), which is a function of the I1 and I4 invariants, has been developed by Harish and Lakshmana Rao [6] as shown in below expression....
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...Recently, Harish and Lakshmana Rao [6] have done uniaxial and biaxial tests on dog bone shape and cruciform shape specimens respectively....
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...Speckle dot tracking algorithm was developed in Matlab code [6] and image viewer tool (for cropping the images) were used to process the image data to obtain the strains from raw image data....
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...W ¼ W1 þW2 þW3 (5) Each of these functions is described in detail below a. Finite anisotropic elastic response Assuming that the mechanical response of PVDF is a transversely isotropic, a polynomial strain energy function (W1), which is a function of the I1 and I4 invariants, has been developed by Harish and Lakshmana Rao [6] as shown in below expression....
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TL;DR: In this article, the authors used two approaches to model cyclic stress with the number of cycles and the effect of cyclic loading on the material, in terms of entropy generation for mechanical and electrical response, is considered for modelling and this approach is adopted to model the PVDF response when subjected to cyclic load.
Abstract: Polyvinylidene fluoride (PVDF) is a piezopolymer, and it has numerous applications as sensors and actuators. Uniaxially stretched PVDF subjected to cyclic stresses finds usage in different applications. Characterising the cyclic response of PVDF through appropriate models is important. In this study, we used two approaches to model cyclic stress with the number of cycles. In the first approach, the evolution equations are used and adopted to model the variation of the cyclic mechanical response of PVDF to track the cyclic response at each time step. In the second approach, the effect of cyclic loading on the material, in terms of entropy generation for mechanical and electrical response, is considered for modelling and this approach is adopted to model the PVDF response when subjected to cyclic loading. The mean stress and voltage variation with the number of cycles are predicted.
References
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01 Jan 1978
4,100 citations
TL;DR: In this article, a review of the 2D digital image correlation (2D DIC) technique for displacement field measurement and strain field estimation is presented, and detailed analyses of the measurement accuracy considering the influences of both experimental conditions and algorithm details are provided.
Abstract: As a practical and effective tool for quantitative in-plane deformation measurement of a planar object surface, two-dimensional digital image correlation (2D DIC) is now widely accepted and commonly used in the field of experimental mechanics. It directly provides full-field displacements to sub-pixel accuracy and full-field strains by comparing the digital images of a test object surface acquired before and after deformation. In this review, methodologies of the 2D DIC technique for displacement field measurement and strain field estimation are systematically reviewed and discussed. Detailed analyses of the measurement accuracy considering the influences of both experimental conditions and algorithm details are provided. Measures for achieving high accuracy deformation measurement using the 2D DIC technique are also recommended. Since microscale and nanoscale deformation measurement can easily be realized by combining the 2D DIC technique with high-spatial-resolution microscopes, the 2D DIC technique should find more applications in broad areas.
2,530 citations
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28 Sep 1997TL;DR: Bonet and Wood as discussed by the authors provide a complete, clear, and unified treatment of nonlinear continuum analysis and finite element techniques under one roof, providing an essential resource for postgraduates studying non-linear continuum mechanics and ideal for those in industry requiring an appreciation of the way in which their computer simulation programs work.
Abstract: Designing engineering components that make optimal use of materials requires consideration of the nonlinear characteristics associated with both manufacturing and working environments. The modeling of these characteristics can only be done through numerical formulation and simulation, and this requires an understanding of both the theoretical background and associated computer solution techniques. By presenting both nonlinear continuum analysis and associated finite element techniques under one roof, Bonet and Wood provide, in this edition of this successful text, a complete, clear, and unified treatment of these important subjects. New chapters dealing with hyperelastic plastic behavior are included, and the authors have thoroughly updated the FLagSHyP program, freely accessible at www.flagshyp.com. Worked examples and exercises complete each chapter, making the text an essential resource for postgraduates studying nonlinear continuum mechanics. It is also ideal for those in industry requiring an appreciation of the way in which their computer simulation programs work.
1,859 citations
"Characterization of the Monotonic U..." refers background in this paper
...The physical meaning of the invariant I4 is it will only give the component of the stretch tensor C corresponding to that direction say it as e2, and C (=F F) is right Cauchy-Green tensor corresponding to reference configuration [15]....
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TL;DR: In this paper, it was shown that the load-deformation curves obtained for certain simple types of deformation of vulcanized rubber test-pieces in terms of a single stored energy function can be interpreted on the basis of the theory of large elastic deformations of incompressible isotropic materials.
Abstract: It is shown in this part how the theory of large elastic deformations of incompressible isotropic materials, developed in previous parts, can be used to interpret the load-deformation curves obtained for certain simple types of deformation of vulcanized rubber test-pieces in terms of a single stored-energy function. The types of experiment described are: (i) the pure homogeneous deformation of a thin sheet of rubber in which the deformation is varied in such a manner that one of the invariants of the strain, I 1 or I 2 , is maintained constant; (ii) pure shear of a thin sheet of rubber (i.e. pure homogeneous deformation in which one of the extension ratios in the plane of the sheet is maintained at unity, while the other is varied); (iii) simultaneous simple extension and pure shear of a thin sheet (i.e. pure homogeneous deformation in which one of the extension ratios in the plane of the sheet is maintained constant at a value less than unity, while the other is varied); (iv) simple extension of a strip of rubber; (v) simple compression (i.e. simple extension in which the extension ratio is less than unity); (vi) simple torsion of a right-circular cylinder; (vii) superposed axial extension and torsion of a right-circular cylindrical rod. It is shown that the load-deformation curves in all these cases can be interpreted on the basis of the theory in terms of a stored-energy function W which is such that δ W /δ I 1 is independent of I 1 and I 2 and the ratio (δ W /δ I 2 ) (δ W /δ I 1 ) is independent of I 1 and falls, as I 2 increases, from about 0*25 at I 2 = 3.
1,137 citations
"Characterization of the Monotonic U..." refers background in this paper
...Rivlin and Saunders, 1951 [10] and Hariharaputhiran and Saravanan 2015 [11] have used non-equibiaxial tests; loading (by constant value) in one direction and unloading in orthogonal direction (constant I1 tests)....
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