Passive Biaxial Tensile Dataset of Three Main Rat Heart Myocardia: Left Ventricle, Mid-Wall and Right Ventricle

Ṋemavhola, Fulufhelo; Ngwangwa, Harry; Davies, Neil; Franz, Thoams

doi:10.20944/preprints202108.0153.v1

Cited by 5 publications

(5 citation statements)

References 11 publications

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“…The mechanical material properties of the sheep trachea were observed to be nonlinear anisotropic and hyperelastic material, similar to other biological soft tissues (Grillo, 1989). Biaxial testing is a reliable method utilised in understanding the mechanical behaviour of soft tissues (Nemavhola, 2017b;Nemavhola et al, 2021b;Nemavhola et al, 2021c;Nemavhola et al, 2021d;Ngwangwa et al, 2022). The data presented in this study covers the circumferential and longitudinal directions.…”

Section: Discussionmentioning

confidence: 94%

“…The excised tissue was cut in approximately 30 mm and 20 mm in longitudinal and circumferential directions, respectively. The tissues were placed in the biaxial device that has hooks attached to a pully system as reported previously (Nemavhola, 2017b;Nemavhola et al, 2021c;Nemavhola, 2021). Vernier calliper was utilised in capturing and measuring the thickness of the tissue in four different points where the average thickness was then utilised for further processing of engineering stresses and strains.…”

Section: Biaxial Mechanical Testingmentioning

confidence: 99%

“…Besides studying the stress-strain behaviour of the tracheal muscle, the mechanical properties of the tissue are studied by examination of the material parameters and performances of six different constitutive material models. The Fung, Choi-Vito, Holzapfel (2000), Holzapfel (2005), Polynomial (Anisotropic) and Four-Fiber Family hyperelastic constitutive models have been previously utilised in studying mechanical behaviour of the soft tissues (Nemavhola et al, 2021c;Lebea et al, 2021). The material parameters obtained from the selected hyperelastic constitutive models are normally utilised in developing finite element models (Kortsmit et al, 2013;Skatulla et al, 2013;Masithulela, 2015a;Nemavhola, 2017a;Nemavhola, 2019a;Nemavhola, 2019b).…”

Section: Introductionmentioning

confidence: 99%

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Experimental analysis and biaxial biomechanical behaviour of ex-vivo sheep trachea

Pandelani,

Ngwangwa,

Nemavhola

2023

Front. Mater.

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Besides surgery, there are currently no other established methods for routine treatment of tracheal pathologies such a tracheal stenosis or tracheal and airway tumors. Even with several attempts to repair the infected trachea with artificial and natural prostheses, there is a need for the fundamental understanding of the tissue’s mechanical behaviour. The purpose of this study was to investigate the mechanical behaviour of the tracheal tissue under biaxial tensile loading. Furthermore, the study examines the material properties of the tissue through a study of the model parameters for six constitutive models. Materials and methods: The fourteen (n = 14) specimens of sheep trachea (Vleis Merino) measured to be ∼30 × 20 mm where only the effective area of ∼25 × 16 mm was subjected to engineering strain. In this study, we assume that the tracheal tissue is anisotropic and incom-pressible, therefore we apply and study the material parameters from six different constitutive material models. Results: The results show that the tracheal tissue is twice as stiff along the circumferential direction as it is along the longitudinal direction. It is also observed that the material properties are different (non-homogeneous) along the trachea. Conclusion: The findings of this study will benefit computational models for the study of tracheal diseases or injuries. Furthermore, these findings will assist in the development of regenerative medicine for different tracheal pathologies and in the bioengineering of replacement tissue in cases of damage.

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Section: Discussionmentioning

confidence: 94%

Section: Biaxial Mechanical Testingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental analysis and biaxial biomechanical behaviour of ex-vivo sheep trachea

Pandelani,

Ngwangwa,

Nemavhola

2023

Front. Mater.

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“…Biaxial tensile testing has been utilised in understanding the mechanical properties of soft tissues. Additionally, hyperelastic constitutive models have also been presented by fitting the constitutive models of the various soft tissues including heart myocardium [56][57][58] and omasum [59].…”

Section: Discussionmentioning

confidence: 99%

Biaxial estimation of biomechanical constitutive parameters of passive porcine sclera soft tissue

Ndlovu¹,

Desai²,

Pandelani³

et al. 2021

Preprint

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This study assesses the modelling capabilities of four constitutive hyperplastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96 %. The polynomial (anisotropic) model gave the best correlation of 98 %. However, the estimated material parameters varied widely from one test to another such that there would be needed to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be needed to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters thereby making it an easier option for application of its material parameters to a finite element model and also requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy more influenced by the fiber-related properties than the background material matrix related properties.

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“…This study is aimed at investigating cross-direction and cross-wall variations in infarcted rat myocardia. Despite many studies that show that the myocardium tissue is complex, nonlinear, anisotropic, and heterogeneous, not enough study has been conducted on the nature of these complexities across the heart's three main walls, namely, the left ventricle (LV), cardiac septum (SPW), and the right ventricle (RV) [19]. In order to accurately bioengineer the heart muscle, it is essential that the passive mechanical behaviour of the real tissue of the entire heart be correctly understood and profiled.…”

Section: Introductionmentioning

confidence: 99%

Determination of Cross-Directional and Cross-Wall Variations of Passive Biaxial Mechanical Properties of Rat Myocardia

et al. 2022

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Heart myocardia are critical to the facilitation of heart pumping and blood circulating around the body. The biaxial mechanical testing of the left ventricle (LV) has been extensively utilised to build the computational model of the whole heart with little importance given to the unique mechanical properties of the right ventricle (RV) and cardiac septum (SPW). Most of those studies focussed on the LV of the heart and then applied the obtained characteristics with a few modifications to the right side of the heart. However, the assumption that the LV characteristics applies to the RV has been contested over time with the realisation that the right side of the heart possesses its own unique mechanical properties that are widely distinct from that of the left side of the heart. This paper evaluates the passive mechanical property differences in the three main walls of the rat heart based on biaxial tensile test data. Fifteen mature Wistar rats weighing 225 ± 25 g were euthanised by inhalation of 5% halothane. The hearts were excised after which all the top chambers comprising the two atria, pulmonary and vena cava trunks, aorta, and valves were all dissected out. Then, 5 × 5 mm sections from the middle of each wall were carefully dissected with a surgical knife to avoid overly pre-straining the specimens. The specimens were subjected to tensile testing. The elastic moduli, peak stresses in the toe region and stresses at 40% strain, anisotropy indices, as well as the stored strain energy in the toe and linear region of up to 40% strain were used for statistical significance tests. The main findings of this study are: (1) LV and SPW tissues have relatively shorter toe regions of 10–15% strain as compared to RV tissue, whose toe region extends up to twice as much as that; (2) LV tissues have a higher strain energy storage in the linear region despite being lower in stiffness than the RV; and (3) the SPW has the highest strain energy storage along both directions, which might be directly related to its high level of anisotropy. These findings, though for a specific animal species at similar age and around the same body mass, emphasise the importance of the application of wall-specific material parameters to obtain accurate ventricular hyperelastic models. The findings further enhance our understanding of the desired mechanical behaviour of the different ventricle walls.

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Passive Biaxial Tensile Dataset of Three Main Rat Heart Myocardia: Left Ventricle, Mid-Wall and Right Ventricle

Cited by 5 publications

References 11 publications

Experimental analysis and biaxial biomechanical behaviour of ex-vivo sheep trachea

Experimental analysis and biaxial biomechanical behaviour of ex-vivo sheep trachea

Biaxial estimation of biomechanical constitutive parameters of passive porcine sclera soft tissue

Determination of Cross-Directional and Cross-Wall Variations of Passive Biaxial Mechanical Properties of Rat Myocardia

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