A hyperelastic model to capture the mechanical behaviour and histological aspects of the soft tissues

2021 ◽  
pp. 105013
Author(s):  
Krashn Kr. Dwivedi ◽  
Piyush Lakhani ◽  
Sachin Kumar ◽  
Navin Kumar
Keyword(s):  
Mechanical Behaviour ◽  
Soft Tissues ◽  
Hyperelastic Model

scholarly journals Constitutive modelling of arteries

2010 ◽  
Vol 466 (2118) ◽  
pp. 1551-1597 ◽  
Author(s):  
Gerhard A. Holzapfel ◽  
Ray W. Ogden
Keyword(s):  
Mechanical Behaviour ◽  
Soft Tissues ◽  
Elastic Strain Energy ◽  
Cylindrical Tube ◽  
Strain Energy Function ◽  
Biological Tissues ◽  
Constitutive Modelling ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Modelling Effort

This review article is concerned with the mathematical modelling of the mechanical properties of the soft biological tissues that constitute the walls of arteries. Many important aspects of the mechanical behaviour of arterial tissue can be treated on the basis of elasticity theory, and the focus of the article is therefore on the constitutive modelling of the anisotropic and highly nonlinear elastic properties of the artery wall. The discussion focuses primarily on developments over the last decade based on the theory of deformation invariants, in particular invariants that in part capture structural aspects of the tissue, specifically the orientation of collagen fibres, the dispersion in the orientation, and the associated anisotropy of the material properties. The main features of the relevant theory are summarized briefly and particular forms of the elastic strain-energy function are discussed and then applied to an artery considered as a thick-walled circular cylindrical tube in order to illustrate its extension–inflation behaviour. The wide range of applications of the constitutive modelling framework to artery walls in both health and disease and to the other fibrous soft tissues is discussed in detail. Since the main modelling effort in the literature has been on the passive response of arteries, this is also the concern of the major part of this article. A section is nevertheless devoted to reviewing the limited literature within the continuum mechanics framework on the active response of artery walls, i.e. the mechanical behaviour associated with the activation of smooth muscle, a very important but also very challenging topic that requires substantial further development. A final section provides a brief summary of the current state of arterial wall mechanical modelling and points to key areas that need further modelling effort in order to improve understanding of the biomechanics and mechanobiology of arteries and other soft tissues, from the molecular, to the cellular, tissue and organ levels.

A novel laparoscopic grasper with two parallel jaws capable of extracting the mechanical behaviour of soft tissues

2017 ◽  
Vol 41 (5) ◽  
pp. 339-345 ◽  
Author(s):  
Dariush Nazarynasab ◽  
Farzam Farahmand ◽  
Alireza Mirbagheri ◽  
Elnaz Afshari
Keyword(s):  
Mechanical Behaviour ◽  
Soft Tissues ◽  
Laparoscopic Grasper

scholarly journals Multi-scale modelling of rubber-like materials and soft tissues: an appraisal

2016 ◽  
Vol 472 (2187) ◽  
pp. 20160060 ◽  
Author(s):  
G. Puglisi ◽  
G. Saccomandi
Keyword(s):  
Mathematical Models ◽  
Phenomenological Models ◽  
Mechanical Behaviour ◽  
Soft Tissues ◽  
Mechanical Response ◽  
Multi Scale ◽  
Bioinspired Materials ◽  
Macroscopic Properties ◽  
Network Scale ◽  
Scale Modelling

We survey, in a partial way, multi-scale approaches for the modelling of rubber-like and soft tissues and compare them with classical macroscopic phenomenological models. Our aim is to show how it is possible to obtain practical mathematical models for the mechanical behaviour of these materials incorporating mesoscopic (network scale) information. Multi-scale approaches are crucial for the theoretical comprehension and prediction of the complex mechanical response of these materials. Moreover, such models are fundamental in the perspective of the design, through manipulation at the micro- and nano-scales, of new polymeric and bioinspired materials with exceptional macroscopic properties.

scholarly journals Characterisation of Skin Biomechanical Properties via Experiment-Numerical Integration

2018 ◽  
Vol 7 (4.26) ◽  
pp. 205
Author(s):  
Nor Fazli Adull Manan ◽  
Linasuriani Muhamad ◽  
Zurri Adam Mohd Adnan ◽  
Mohd Azman Yahaya ◽  
Jamaluddin Mahmud
Keyword(s):  
Mechanical Properties ◽  
Constitutive Equation ◽  
Numerical Integration ◽  
Soft Tissues ◽  
Biomechanical Properties ◽  
Test Machine ◽  
Medical Sciences ◽  
Ogden Model ◽  
Hyperelastic Model ◽  
Load Displacement

By having specific mechanical properties of skin, computational program and analysis become more reliable by showing the real skin behaviour. Up to date, mechanical properties of biological soft tissues (skin) haven’t been accepted solely for official usage. Therefore, characterisation of the skin biomechanical properties might contribute a new knowledge to the engineering and medical sciences societies. This paper highlights the success in characterising the hyperelastic parameters of leporine (rabbit) skin via experimental-numerical integration. A set of five sample of leporine skin were stretched using the conventional tensile test machine to generate the load-displacement graphs. Based on the Ogden’s constitutive equation and Mooney-Rivlin hyperelastic model, a stress-stretch equation was developed and a programme was written using Matlab. By varying the Ogden’s and Mooney-Rivlin’s parameters, the programme was capable of plotting stress-stretch and load-displacement graphs. The graphs that best match the experimental results will constitut to the corresponding coefficient, µ, and α for Ogden Model and C1 and C2 material parameter for Mooney-Rivlin Model that will best describe the behaviour of the leporine skin. The current results show that the Ogden’s coefficient and exponent for the subject was estimated to be (μ = 0.048MPa, α = 7.073) & (μ = 0.020MPa, α = 9.249) for Anterior-Posterior (AP) and Dorsal-Ventral (DV) respectively for Ogden Model. Meanwhile the value for Mooney-Rivlin Model were estimated to be (C1 = 1.271, C2 = 1.868) & (C1 = 1.128, C2 = 1.537) for AP and DV respectively, which is in close agreement to results found by other researchers. Further analyses for comparison could be carried out by developing mathematical model based on other constitutive equation such as Arruda-Boyce and Neo-Hookean. Nevertheless, this study has contributed to the knowledge about skin behaviour and the results are useful for references.  

Soft composite based hyperelastic model for anisotropic tissue characterization

2020 ◽  
Vol 54 (28) ◽  
pp. 4525-4534 ◽  
Author(s):  
Arnab Chanda ◽  
Subhodip Chatterjee ◽  
Vivek Gupta
Keyword(s):  
Fiber Orientation ◽  
Strain Energy ◽  
Soft Tissues ◽  
Volume Fraction ◽  
Deformation Gradient ◽  
Model Parameters ◽  
Hyperelastic Model ◽  
Fiber Matrix ◽  
Soft Composite

Soft tissues are complex anisotropic composite systems comprising of multiple differently oriented layers of fiber embedded within a soft matrix. To date, soft tissues have been mainly characterized using simplified linear elastic material models, isotropic viscoelastic and hyperelastic models, and transversely isotropic models. In such models, the effect of fiber volume fraction (FVF), fiber orientation, and fiber-matrix interactions are missing, inhibiting accurate characterization of anisotropic tissue properties. The current work addresses this literature gap with the development of a novel soft composite based material framework to model tissue anisotropy. In this model, the fiber and matrix are considered as separate hyperelastic materials, and fiber-matrix interaction is modeled using multiplicative decomposition of the deformation gradient. The effect of the individual contribution of the fibers and matrix are introduced into the numerical framework for a single soft composite layer, and fiber orientation effects are incorporated into the strain energy functions. Also, strain energy formulations are developed for multiple soft composite layers with varying fiber orientations and contributions, describing the biomechanical behavior of an entire anisotropic tissue block. Stress-strain relationships were derived from the strain energy equations for a uniaxial mechanical test condition. To validate the model parameters, experimental models of soft composites tested under uniaxial tension were characterized using the novel anisotropic hyperelastic model (R2 = 0.983). To date, such a robust anisotropic hyperelastic composite framework has not been developed, which would be indispensable for experimental characterization of tissues and for improving the fidelity of computational biological models in future.

Hyperelastic Model Selection of Tissue Mimicking Phantom Undergoing Large Deformation and Finite Element Modeling for Elastic and Hyperelastic Material Properties

2011 ◽  
Vol 415-417 ◽  
pp. 2116-2120 ◽  
Author(s):  
Sara Golbad ◽  
Mohammad Haghpanahi
Keyword(s):  
Finite Element ◽  
Large Deformation ◽  
Material Properties ◽  
Soft Tissues ◽  
Nonlinear Behavior ◽  
Strain Energy Function ◽  
Strain Curve ◽  
Breast Cancer Diagnosis ◽  
Hyperelastic Material ◽  
Hyperelastic Model

Pathologies in soft tissues are associated with changes in their elastic properties. Tumor tissues are usually stiffer than the fat tissues and other normal tissues and show the nonlinear behavior in large deformations. There have been a lot of researches about elastography (linear and nonlinear) as a new detecting technique based on mechanical behavior of tissue. In order to formulate the tissue’s nonlinear behavior, a strain energy function is required. For better estimation of nonlinear tissue parameters in elasticity imaging, non linear stress-strain curve of phantom is used. This work presents hyperelastic measurement results of tissue-mimicking phantom undergoing large deformation during uniaxial compression. For phantom samples, 8 hyperelastic models have been used. The results indicate that polynomial model with N=2 is the most accurate in terms of fitting experimental data. To compare the results between elastic and hyperelastic model, a 3-D finite element numerical model developed based on two different materials of elastic and hyperelastic material properties. The comparison confirm the approach of other recent studies about necessity of hyperelastic elastography and state that hyperelastic elastography should be used to formulate a technique for breast cancer diagnosis.

Isotropic incompressible hyperelastic models for modelling the mechanical behaviour of biological tissues: a review

2015 ◽  
Vol 60 (6) ◽  
Author(s):  
Cora Wex ◽  
Susann Arndt ◽  
Anke Stoll ◽  
Christiane Bruns ◽  
Yuliya Kupriyanova
Keyword(s):  
Mechanical Behaviour ◽  
Strain Energy ◽  
Soft Tissues ◽  
Strain Energy Function ◽  
Biological Tissues ◽  
Tissue Response ◽  
Large Strains ◽  
Energy Functions ◽  
Strain Energy Functions ◽  
Hyperelastic Models

AbstractModelling the mechanical behaviour of biological tissues is of vital importance for clinical applications. It is necessary for surgery simulation, tissue engineering, finite element modelling of soft tissues, etc. The theory of linear elasticity is frequently used to characterise biological tissues; however, the theory of nonlinear elasticity using hyperelastic models, describes accurately the nonlinear tissue response under large strains. The aim of this study is to provide a review of constitutive equations based on the continuum mechanics approach for modelling the rate-independent mechanical behaviour of homogeneous, isotropic and incompressible biological materials. The hyperelastic approach postulates an existence of the strain energy function – a scalar function per unit reference volume, which relates the displacement of the tissue to their corresponding stress values. The most popular form of the strain energy functions as Neo-Hookean, Mooney-Rivlin, Ogden, Yeoh, Fung-Demiray, Veronda-Westmann, Arruda-Boyce, Gent and their modifications are described and discussed considering their ability to analytically characterise the mechanical behaviour of biological tissues. The review provides a complete and detailed analysis of the strain energy functions used for modelling the rate-independent mechanical behaviour of soft biological tissues such as liver, kidney, spleen, brain, breast, etc.

scholarly journals Modelling indentation of human lower-limb soft tissue: simulation parameters and their effects

2020 ◽  
Author(s):  
Theodoros Marinopoulos ◽  
Lorenzo Zani ◽  
Simin Li ◽  
Vadim V. Silberschmidt
Keyword(s):  
Finite Element ◽  
Mechanical Behaviour ◽  
Lower Limb ◽  
Soft Tissues ◽  
High Sensitivity ◽  
Biological Tissues ◽  
Finite Element Models ◽  
Mechanical Responses ◽  
Reaction Forces ◽  
Human Participants

Abstract Modern developments of biomedical applications demand a better understanding of mechanical behaviour of soft biological tissues. As human soft tissues demonstrate a significant structural and functional diversity, characterisation of their mechanical behaviour still remains a challenge. Limitations related with implementation of mechanical experiments on human participants lead to a use of finite-element models for analysis of mechanical responses of soft tissues to different loads. This study focuses on parameters of numerical simulation considered for modelling of indentation of a human lower limb. Assessment of the effect of boundary conditions on the model size shows that at a ratio of its length to the tissue’s thickness of 1.7 for the 3D model this effect vanishes. The numerical results obtained with models employing various sets of mechanical parameters of the first-order Ogden scheme were compared with original experimental data. Furthermore, high sensitivity of the resulting reaction forces to the indenting direction is demonstrated for cases of both linear and angular misalignments of the indenter. Finally, the effect of changes in material parameters and their domain on their contribution to the reaction forces is discussed with the aim to improve our understanding of mechanical behaviour of soft tissues based on numerical methods. The undertaken research with its results on minimal requirements for finite-element models of indentation of soft tissues can support inverse analysis of their mechanical properties and underpin orthopaedic and medical procedures.

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