Finite Amplitude Azimuthal Shear Waves in a Compressible Hyperelastic Solid

2000 ◽  
Vol 68 (2) ◽  
pp. 145-152 ◽  
Author(s):  
J. B. Haddow ◽  
L. Jiang
Keyword(s):  
Wave Propagation ◽  
Longitudinal Wave ◽  
Shear Wave ◽  
Strain Energy ◽  
Numerical Solutions ◽  
Numerical Procedure ◽  
Strain Energy Function ◽  
Finite Amplitude ◽  
Plane Shear ◽  
Azimuthal Shear

Lagrangian equations of motion for finite amplitude azimuthal shear wave propagation in a compressible isotropic hyperelastic solid are obtained in conservation form with a source term. A Godunov-type finite difference procedure is used along with these equations to obtain numerical solutions for wave propagation emanating from a cylindrical cavity, of fixed radius, whose surface is subjected to the sudden application of a spatially uniform azimuthal shearing stress. Results are presented for waves propagating radially outwards; however, the numerical procedure can also be used to obtain solutions if waves are reflected radially inwards from a cylindrical outer surface of the medium. A class of strain energy functions is considered, which is a compressible generalization of the Mooney-Rivlin strain energy function, and it is shown that, for this class, an azimuthal shear wave can not propagate without a coupled longitudinal wave. This is in contrast to the problem of finite amplitude plane shear wave propagation with the neo-Hookean generalization, for which a shear wave can propagate without a coupled longitudinal wave. The plane problem is discussed briefly for comparison with the azimuthal problem.

General Deformations of Neo-Hookean Membranes

1973 ◽  
Vol 40 (1) ◽  
pp. 7-12 ◽  
Author(s):  
W. H. Yang ◽  
C. H. Lu
Keyword(s):  
Differential Equations ◽  
Strain Energy ◽  
Numerical Solutions ◽  
Nonlinear Partial Differential Equations ◽  
Strain Energy Function ◽  
Finite Deformations ◽  
Finite Difference Approximation ◽  
Difference Approximation ◽  
Special Cases ◽  
Convergent Algorithm

A set of three nonlinear partial-differential equations is derived for general finite deformations of a thin membrane. The material that composes the membrane is assumed to be hyperelastic. Its mechanical property is represented by the neo-Hookean strain-energy function. The equations reduce to special cases known in the literature. A fast convergent algorithm is developed. The numerical solutions to the finite-difference approximation of the differential equations are computed iteratively with a trivial initial iterant. As an example, the problem of inflating a rectangular membrane with fixed edges by a uniform pressure applied on one side is presented. The solutions and their convergence are displayed and discussed.

Nonlinear Elastic Constitutive Relations of Auxetic Honeycombs

2009 ◽  
Author(s):  
Jaehyung Ju ◽  
Joshua D. Summers ◽  
John Ziegert ◽  
Georges Fadel
Keyword(s):  
Cell Walls ◽  
Strain Energy ◽  
Constitutive Relations ◽  
Effective Strain ◽  
Strain Energy Function ◽  
Periodic Boundary Conditions ◽  
Plane Shear ◽  
Local Cell ◽  
Nonlinear Elastic ◽  
Nonlinear Constitutive Relation

When designing a flexible structure consisting of cellular materials, it is important to find the maximum effective strain of the cellular material resulting from the deformed cellular geometry and not leading to local cell wall failure. In this paper, a finite in-plane shear deformation of auxtic honeycombs having effective negative Poisson’s ratio is investigated over the base material’s elastic range. An analytical model of the inplane plastic failure of the cell walls is refined with finite element (FE) micromechanical analysis using periodic boundary conditions. A nonlinear constitutive relation of honeycombs is obtained from the FE micromechanics simulation and is used to define the coefficients of a hyperelastic strain energy function. Auxetic honeycombs show high shear flexibility without a severe geometric nonlinearity when compared to their regular counterparts.

Evaluating the response of a modified Gent-Thomas strain energy function having limiting chain extensibility condition in torsion and azimuthal shear

2021 ◽  
pp. 096739112110033
Author(s):  
Amir Ghafouri Sayyad ◽  
Ali Imam ◽  
Shahram Etemadi Haghighi
Keyword(s):  
Strain Energy ◽  
Angular Displacement ◽  
Strain Energy Function ◽  
The Other ◽  
Thomas Model ◽  
Torsional Response ◽  
Energy Models ◽  
Azimuthal Shear ◽  
Limiting Chain Extensibility ◽  
Incompressible Cylinder

The purpose of this paper is to investigate the torsion and azimuthal shear of an incompressible hyperelastic cylinder having a modified Gent-Thomas strain energy with limiting chain extensibility condition. First, the torsional response of the modified Gent-Thomas model is obtained analytically and compared with those of Gent-Gent, Gent-Thomas, and Carroll strain energy models where the former model incorporates the limiting chain extensibility condition while the latter two are phenomenological models. The results show the modified Gent-Thomas model to be in better agreement with the experimental data of Rivlin and Saunders on torsion than the other three models. To further evaluate the response of the modified Gent-Thomas model, azimuthal shear deformation of an incompressible hyperelastic cylinder with the modified Gent-Thomas, Gent-Thomas, Gent-Gent, and Carroll strain energies is considered, where the angular displacement in azimuthal shear is determined analytically for the first three models and numerically for the fourth model. It is shown that the strain hardening effect, predicted either by the limiting chain extensibility condition for the modified Gent-Thomas and Gent-Gent models or phenomenologically by the Carroll model, is quite significant in the azimuthal shear response of the incompressible cylinder.

scholarly journals Joined dissimilar orthotropic elastic cylindrical membranes under internal pressure and longitudinal tension

1993 ◽  
Vol 34 (3) ◽  
pp. 296-317 ◽  
Author(s):  
V. G. Hart ◽  
Jingyu Shi
Keyword(s):  
Internal Pressure ◽  
Energy Function ◽  
Strain Energy ◽  
Numerical Solutions ◽  
Circumferential Stress ◽  
Strain Energy Function ◽  
The Body ◽  
Surgical Implants ◽  
Elastic Membranes ◽  
Preliminary Study

AbstractFollowing work in an earlier paper, the theory of finite deformation of elastic membranes is applied to the problem of two initially-circular semi-infinite cylindrical membranes of the same radius but of different material, joined longitudinally at a cross-section. The body is inflated by constant interior pressure and is also extended longitudinally. The exact solution found for an arbitrary material is now specialised to the orthotropic case, and the results are interpreted for forms of the strain-energy function introduced by Vaishnav and by How and Clarke in connection with the study of arteries. Also considered in this context is the similar problem where two semi-infinite cylindrical membranes of the same material are separated by a cuff of different material. Numerical solutions are obtained for various pressures and longitudinal extensions. It is shown that discontinuities in the circumferential stress at the joint can be reduced by suitable choice of certain coefficients in the expression defining the strain-energy function. The results obtained here thus solve the problem of static internal pressure loading in extended dissimilar thin orthotropic tubes, and may also be useful in the preliminary study of surgical implants in arteries.

New Strain Energy Function for Acoustoelastic Analysis of Dilatational Waves in Nearly Incompressible, Hyper-Elastic Materials

2005 ◽  
Vol 72 (6) ◽  
pp. 843-851 ◽  
Author(s):  
H. Kobayashi ◽  
R. Vanderby
Keyword(s):  
Wave Propagation ◽  
Energy Function ◽  
Strain Energy ◽  
Constitutive Models ◽  
Strain Energy Function ◽  
Deformation Tensor ◽  
Energy Functions ◽  
Dilatational Wave ◽  
Hyper Elastic ◽  
Strain Energy Functions

Acoustoelastic analysis has usually been applied to compressible engineering materials. Many materials (e.g., rubber and biologic materials) are “nearly” incompressible and often assumed incompressible in their constitutive equations. These material models do not admit dilatational waves for acoustoelastic analysis. Other constitutive models (for these materials) admit compressibility but still do not model dilatational waves with fidelity (shown herein). In this article a new strain energy function is formulated to model dilatational wave propagation in nearly incompressible, isotropic materials. This strain energy function requires four material constants and is a function of Cauchy–Green deformation tensor invariants. This function and existing (compressible) strain energy functions are compared based upon their ability to predict dilatational wave propagation in uniaxially prestressed rubber. Results demonstrate deficiencies in existing functions and the usefulness of our new function for acoustoelastic applications. Our results also indicate that acoustoelastic analysis has great potential for the accurate prediction of active or residual stresses in nearly incompressible materials.

Some dynamic properties of a prestressed incompressible hyperelastic material

1973 ◽  
Vol 8 (1) ◽  
pp. 61-73 ◽  
Author(s):  
J.A. Belward
Keyword(s):  
Wave Propagation ◽  
Plane Wave ◽  
Energy Function ◽  
Strain Energy ◽  
Dynamic Properties ◽  
Strain Energy Function ◽  
Hyperelastic Material ◽  
Elastic Materials ◽  
Incompressible Hyperelastic Material ◽  
Plane Wave Propagation

The work continues some earlier investigations into dynamic properties of prestressed incompressible elastic materials. Whereas the material was previously assumed to be a Mooney material, it is here allowed to have any strain energy function. Plane wave propagation and the motions caused by an impulsive line of traction are examined. The results obtained are compared with the earlier work.

Biaxial Mechanical Response of Bioprosthetic Heart Valve Biomaterials to High In-plane Shear

2003 ◽  
Vol 125 (3) ◽  
pp. 372-380 ◽  
Author(s):  
Wei Sun ◽  
Michael S. Sacks ◽  
Tiffany L. Sellaro ◽  
William S. Slaughter ◽  
Michael J. Scott
Keyword(s):  
Soft Tissue ◽  
Strain Energy ◽  
Mechanical Response ◽  
Strain Energy Function ◽  
Elastic Response ◽  
Model Parameters ◽  
Shear Stresses ◽  
High Shear ◽  
Plane Shear ◽  
Fung Model

Utilization of novel biologically-derived biomaterials in bioprosthetic heart valves (BHV) requires robust constitutive models to predict the mechanical behavior under generalized loading states. Thus, it is necessary to perform rigorous experimentation involving all functional deformations to obtain both the form and material constants of a strain-energy density function. In this study, we generated a comprehensive experimental biaxial mechanical dataset that included high in-plane shear stresses using glutaraldehyde treated bovine pericardium (GLBP) as the representative BHV biomaterial. Compared to our previous study (Sacks, JBME, v.121, pp. 551–555, 1999), GLBP demonstrated a substantially different response under high shear strains. This finding was underscored by the inability of the standard Fung model, applied successfully in our previous GLBP study, to fit the high-shear data. To develop an appropriate constitutive model, we utilized an interpolation technique for the pseudo-elastic response to guide modification of the final model form. An eight parameter modified Fung model utilizing additional quartic terms was developed, which fitted the complete dataset well. Model parameters were also constrained to satisfy physical plausibility of the strain energy function. The results of this study underscore the limited predictive ability of current soft tissue models, and the need to collect experimental data for soft tissue simulations over the complete functional range.

Anti-Plane Shear Wave in Microstructural Media

2020 ◽  
pp. 376-411
Author(s):  
Mriganka Shekhar Chaki ◽  
Abhishek Kumar Singh
Keyword(s):  
Wave Propagation ◽  
Shear Wave ◽  
Numerical Study ◽  
Plane Shear ◽  
Algebraic Form ◽  
New Type ◽  
Common Interface ◽  
The Common ◽  
Irregular Interface ◽  
Perfect Interface

The present chapter encapsulates the characteristic behavior of anti-plane shear wave propagation in a micropolar layer/semi-infinite structural media. Two types of interfacial complexity have been considered at the common interface which give rise to two distinct mathematical models: (1) Model I: Anti-plane shear wave in a micropolar layer/semi-infinite structure with rectangular irregular interface and (2) Model II: Anti-plane shear wave in a micropolar layer/semi-infinite structure with non-perfect interface. For both models, dispersion equations have been deduced in algebraic-form and in particular, the dispersion equation of new type of surface wave resulted due to micropolarity has been obtained. The deduced results have been validated with classical cases analytically. The effects of micropolarity, irregularity, and non-perfect interface on anti-plane shear wave have been demonstrated through numerical study in the present chapter.

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