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Optimization of Cardiac Fiber Orientation for Homogeneous Fiber Strain During Ejection (1999)

Rijcken, J. ; Bovendeerd, P. H. M. ; Schoofs, A. J. G. ; [et al.]

Springer

Annals of biomedical engineering 27 (1999), S. 289-297

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ISSN: 1573-9686

Keywords: Left ventricle ; Finite-element analysis

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine , Technology

Notes: Abstract The strain of muscle fibers in the heart is likely to be distributed uniformly over the cardiac walls during the ejection period of the cardiac cycle. Mathematical models of left ventricular (LV) wall mechanics have shown that the distribution of fiber strain during ejection is sensitive to the orientation of muscle fibers in the wall. In the present study, we tested the hypothesis that fiber orientation in the LV wall is such that fiber strain during ejection is as homogeneous as possible. A finite-element model of LV wall mechanics was set up to compute the distribution of fiber strain at the beginning (BE) and end (EE) of the ejection period of the cardiac cycle, with respect to a middiastolic reference state. The distribution of fiber orientation over the LV wall, quantified by three parameters, was systematically varied to minimize regional differences in fiber shortening during ejection and in the average of fiber strain at BE and EE. A well-defined optimum in the distribution of fiber orientation was found which was not significantly different from anatomical measurements. After optimization, the average of fiber strain at BE and EE was 0.025 ± 0.011 (mean ± standard deviation) and the difference in fiber strain during ejection was 0.214 ± 0.018. The results indicate that the LV structure is designed for maximum homogeneity of fiber strain during ejection. © 1999 Biomedical Engineering Society. PAC99: 8719Hh, 8710+e, 8719Ff, 8719Rr, 0270Dh

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1114/1.147

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On the consistency of four different control surfaces used for finite area blade-to-blade flow calculations (1984)

Arts, T.

Chichester : Wiley-Blackwell

International Journal for Numerical Methods in Fluids 4 (1984), S. 1083-1095

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ISSN: 0271-2091

Keywords: Turbomachines ; Finite Volume ; Consistency ; Engineering ; Engineering General

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: The aim of this contribution is to investigate the consistency and order of accuracy of different control surfaces used for finite area blade-to-blade flow calculations. The following cases will be treated: a hexagonal element, a trapezoidal element, a bitrapezoidal element and a quadrilateral element. Finally, the consistency conditions will be discussed and compared with respect to a cascade flow application.

Additional Material: 6 Ill.