Investigation of the effect of high +Gz accelerations on human cardiac function

Jamshidi, Maziar; Ahmadian, M.T.

doi:10.1016/j.jmbbm.2013.06.008

Cited by 8 publications

(6 citation statements)

References 30 publications

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“…The magnitude of strains, complete coaptation in the systolic phase, leaflet deformations and closed valve configurations are in correlation with findings of previous studies. 22,23,25 The percentage difference of principal strain between the healthy model and surgically repaired one, was about 8%, in systolic phase, regarding the diastolic phase the difference observed was negligible, approximately 2%.…”

Section: Discussionmentioning

confidence: 87%

“…21 Under exposure to acceleration loading (from + 1 to + 6G) in the upward direction of the human body, diminution in left ventricle volume in diastolic phase and escalation in stress values observed. 22 However, study neglects mitral valve, and in material modeling the myocardium's mechanical characteristics are derived from uniaxial compression experiments on bovine heart tissue samples. Simulation of healthy and edge-to-edge repair mitral valve in both systolic and diastolic phases, under exposure to + 6G crash acceleration accomplished.…”

Section: Introductionmentioning

confidence: 99%

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Fluid-structure interaction and structural simulation of high acceleration effects on surgical repaired human mitral valve biomechanics

Khalili,

Asgari

2023

Proc Inst Mech Eng H

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Mitral valve dynamics depend on force stability in the mitral leaflets, the mitral annulus, the chordae tendineae, and the papillary muscles. In chordal rupture conditions, the proper function of the valve disrupts, causing mitral regurgitation, the most prevalent valvular disease. In this study, Structural and FSI frameworks were employed to study valve dynamics in healthy, pathologic, and repaired states. Anisotropic, non-linear, hyper-elastic material properties applied to tissues of the valve while the first-order Ogden model reflected the best compatibility with the empirical data. Hemodynamic blood pressure of the cardiovascular system is applied on the leaflets as uniform loads varying by time, and exposure to high acceleration loads imposed on models. Immersed boundary method used for simulation of fluid in a cardiac cycle. In comparison between healthy and pathologic models, stress values and chordal tensions are increased, by nearly threefold and twofold, respectively. Stress concentration on leaflets is reduced by 75% after performing a successful surgical repair on the pathological model. Crash acceleration loads led to more significant stress and chordae tension on models, by 27% and 23%, respectively. It is concluded that a more sophisticated model could lead to a better understanding of human heart valve biomechanics in various conditions. If a preoperative plan is developed based on these modeling methods, the requirement for multiple successive repairs would be eliminated, operative times are shortened, and patient outcomes are improved.

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Section: Discussionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Fluid-structure interaction and structural simulation of high acceleration effects on surgical repaired human mitral valve biomechanics

Khalili,

Asgari

2023

Proc Inst Mech Eng H

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“…Mansouri and Darijani [4] utilized this test data for proofing of robustness of the invariants model and showed the invariants model fitted both of the pure shear and uniaxial tension loading. The silicone rubber is common material in biomechanical applications because of its unique properties and excellent biocompatibility [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27].The material constants of the porcine liver tissue and unfilled silicone rubber can be seen in Table 1.…”

Section: Experimental Datamentioning

confidence: 99%

“…Results indicated that the Haines-Wilson, Gent, and Ogden models can present proper behavior of the silicone rubber and the Mooney-Rivlin model prediction is not satisfactory. Jamshidi and Ahmadianused the Mooney-Rivlin, polynomial, Yeoh, and Ogden models to represent the mechanical properties of heart tissues and found the Yeoh material model as the best one [13]. Kaster et al [14] employed the polynomial, Yeoh, Arruda-Boyce and Ogden models for accurate characterization of the mechanical behavior of brain tissue.…”

Section: Introductionmentioning

confidence: 99%

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Elimination of Pseudo Initial Stress for Proposed Invariants based Hyper elastic Strain Energy

Narooei¹

2018

OAJBEB

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Although fitting of experimental data is important in selection of the best hyper elastic strain energy function, the zero stress condition in the initial (unstressed) configuration also should be taken into account. Therefore, in the current research a modification for an invariants based model was developed to eliminate the pseudo initial stress. To this goal, additional terms were added to hyper elastic strain energy as a function of the right Cauchy-Green deformation tensor. To justify the proposed algorithm, uniaxial loading of liver tissue and unfilled silicone rubber were studied via constitutive modeling in VUMAT user subroutine of ABAQUS software. Excellent agreement between the experimental and numerically predicted stress-stretch curves showed that the modified strain energy function enables to characterize the mechanical behavior of the liver tissue and unfilled silicone rubber. As the deformed shapes of soft tissues are important especially in the surgery operations, the effect of modification on the final deformed geometry was investigated. Results were shown the deformed profile of the modified and unmodified hyper elastic strain energy models were different.

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Harnessing Gravity‐Induced Instability of Soft Materials: Mechanics and Application

Lü,

Li,

et al. 2024

Adv Funct Materials

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This work offers a comprehensive overview of how gravity affects soft materials, with a particular emphasis on gravity‐induced instability. Soft materials, including biological tissues, elastomers, and gels, are characterized by low elastic moduli and the ability to undergo significant deformations. These large deformations can lead to instabilities and the emergence of distinctive surface patterns when even small perturbations are introduced. An in‐depth understanding of these gravity‐induced instabilities in soft materials is of paramount importance for both fundamental scientific research and practical applications across diverse domains. The underlying mechanisms governing these instabilities are delved in and elucidate the techniques employed to study and manipulate them. Further, the gravity‐induced wrinkling and the Rayleigh‐Taylor (RT) instability in soft materials are zoomed in, highlighting how altered gravity environments impact natural and synthetic systems. Lastly, current and potential applications are underscored where gravity‐induced instabilities are already making an impact or may hold promise in the near future. In sum, the exploration of gravity‐induced instabilities in soft materials paves the way for innovative applications and advancements in a wide range of fields.

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Investigation of the effect of high +Gz accelerations on human cardiac function

Cited by 8 publications

References 30 publications

Fluid-structure interaction and structural simulation of high acceleration effects on surgical repaired human mitral valve biomechanics

Fluid-structure interaction and structural simulation of high acceleration effects on surgical repaired human mitral valve biomechanics

Elimination of Pseudo Initial Stress for Proposed Invariants based Hyper elastic Strain Energy

Harnessing Gravity‐Induced Instability of Soft Materials: Mechanics and Application

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