scholarly journals A Simplified Rotational Spring Model for Mitral Valve Dynamics

2010 ◽  
Author(s):  
K.T. Moorhead ◽  
P. Kolh ◽  
S. Paeme ◽  
J.G. Chase ◽  
C.E. Hann ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Spring Model ◽  
Rotational Spring ◽  
Valve Dynamics ◽  
Rotational Spring Model

An analytical method for full-range mechanical behavior of continuous slab-deck in multi-span simply supported concrete bridges

2021 ◽  
pp. 136943322110427
Author(s):  
Xiang Zhang ◽  
Quan-Sheng Yan ◽  
Bu-Yu Jia ◽  
Zheng Yang ◽  
Ying-Hao Zhao ◽  
...  
Keyword(s):  
Nonlinear Analysis ◽  
Full Range ◽  
Scale Model ◽  
Axial Stiffness ◽  
Spring Model ◽  
Analysis Model ◽  
Rotational Spring ◽  
Simply Supported ◽  
Continuous Slab ◽  
Rotational Spring Model

Connecting the ends of girders with a continuous slab-deck to make a multiple-span simply supported girder bridge provides many benefits, but there is no suitable nonlinear analysis model which considers continuous slab-deck cracking under tension and bending. In this article, the rotational spring model is further refined to replace the restraining effects at both ends of the girder by the simplified mechanical model associated with axial stiffness, bending stiffness, and shear stiffness. Then, it is introduced into the analysis of continuous slab-deck. The more accurate rotations and displacements of both ends of continuous slab-deck are obtained to investigate the more precise moment and tension of the continuous slab-deck. Furthermore, this article presents an improved nonlinear analysis model of continuous slab-deck based on a detailed boundary rotational spring model. The displacements of important positions and the strain of key components in continuous slab-deck after cracking are investigated by numerical analysis and full-scale model test to verify the accuracy of the proposed nonlinear analysis model. The result shows that the nonlinear analysis model presented in this article could successfully evaluate the depth of cracks and the stress of rebars in continuous slab-deck, and it is instructional in predicting the cracking state of the continuous slab-deck and the reinforcement design.

Coordinate-Free Analysis of Mitral Valve Dynamics in Normal and Ischemic Hearts

Circulation ◽  
2000 ◽  
Vol 102 (suppl_3) ◽  
Author(s):  
Paul Dagum ◽  
Tomasz A. Timek ◽  
G. Randall Green ◽  
David Lai ◽  
George T. Daughters ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Color Doppler ◽  
Mitral Annulus ◽  
Left Ventricular ◽  
Free System ◽  
Ring Annuloplasty ◽  
3D Geometry ◽  
Valve Function ◽  
Valve Dynamics ◽  
Radiopaque Markers

Background —The purpose of this investigation was to study mitral valve 3D geometry and dynamics by using a coordinate-free system in normal and ischemic hearts to gain mechanistic insight into normal valve function, valve dysfunction during ischemic mitral regurgitation (IMR), and the treatment effects of ring annuloplasty. Methods and Results —Radiopaque markers were implanted in sheep: 9 in the ventricle, 1 on each papillary tip, 8 around the mitral annulus, and 1 on each leaflet edge midpoint. One group served as a control (n=7); all others underwent flexible Tailor partial (n=5) or Duran complete (n=6) ring annuloplasty. After an 8±2-day recovery, 3D marker coordinates were measured with biplane videofluoroscopy before and during posterolateral left ventricular ischemia, and MR was assessed by color Doppler echocardiography. Papillary to annular distances remained constant throughout the cardiac cycle in normal hearts, during ischemia, and after ring annuloplasty with either type of ring. Papillary to leaflet edge distances similarly remained constant throughout ejection. During ischemia, however, the absolute distances from the papillary tips to the annulus changed in a manner consistent with leaflet tethering, and IMR was observed. In contrast, during ischemia in either ring group, those distances did not change from preischemia, and no IMR was observed. Conclusions —This analysis uncovered a simple pattern of relatively constant intracardiac distances that describes the 3D geometry and dynamics of the papillary tips and leaflet edges from the dynamic mitral annulus. Ischemia perturbed the papillary-annular distances, and IMR occurred. Either type of ring annuloplasty prevented such changes, preserved papillary-annular distances, and prevented IMR.

FSI Modeling of Prosthetic Mitral Valve Dynamics and Left Ventricular Flow during Diastole

2013 ◽  
Author(s):  
Su Boyang ◽  
Zhong Liang ◽  
Cui Fangsen ◽  
Kumar Gideon Praveen ◽  
Phang Hui Qun ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Left Ventricular ◽  
Valve Dynamics ◽  
Prosthetic Mitral Valve

Image-based mass-spring model of mitral valve closure for surgical planning

2008 ◽  
Author(s):  
Peter E. Hammer ◽  
Douglas P. Perrin ◽  
Pedro J. del Nido ◽  
Robert D. Howe
Keyword(s):  
Mitral Valve ◽  
Surgical Planning ◽  
Valve Closure ◽  
Spring Model ◽  
Mass Spring Model ◽  
Mass Spring

scholarly journals 1035-216 Mitral valve dynamics with different pacing sites

2004 ◽  
Vol 43 (5) ◽  
pp. A112
Author(s):  
Frank Langer ◽  
Frederick A Tibayan ◽  
Filiberto Rodriguez ◽  
Tomasz Timek ◽  
Mary K Zasio ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Valve Dynamics

On Mitral Valve Dynamics and its Connection to Early Diastolic Flow

2008 ◽  
Vol 37 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Arash Kheradvar ◽  
Morteza Gharib
Keyword(s):  
Mitral Valve ◽  
Diastolic Flow ◽  
Valve Dynamics
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