当前位置： SCI文献检索 > Acta Biomaterialia期刊下所有文献 > Rate-dependency of the mechanical behaviour of semilunar heart valves under biaxial deformation.

Rate-dependency of the mechanical behaviour of semilunar heart valves under biaxial deformation.

Abstract：

:This paper presents an experimental investigation and evidence of rate-dependency in the planar mechanical behaviour of semilunar heart valves. Samples of porcine aortic and pulmonary valves were subjected to biaxial deformations across 1000-fold stretch rate, ranging from λ̇=0.001 to 1 s-1. The experimental campaign encompassed protocols covering (i) tests on samples without preconditioning, (ii) preconditioning immediately followed by tensile tests; and (iii) tensile tests at different rates performed on the same preconditioned specimen. Our results indicate that under all employed loading protocols, heart valve samples exhibit a marked rate-dependency in their deformation behaviour. This rate-dependency is reflected in stress-stretch curves and the calculated ensuing gradients, where samples typically show stiffening with increased rate. These results underpin one conclusive outcome: the in-plane mechanical behaviour of semilunar valves is rate-dependent (p<0.05 for Cauchy stress levels ≥50 kPa). This outcome implies that the rate of deformation for characterising the mechanical behaviour of semilunar heart valves may not be chosen arbitrarily low, and models that incorporate rate-effects may be more appropriate for better capturing the mechanical behaviour of heart valves. STATEMENT OF SIGNIFICANCE: This study presents for the first time a comprehensive set of results and evidence of rate-dependency in the mechanical behaviour of semilunar heart valves under biaxial deformation. Our results challenge the widely-applied assumption in the bulk of the existing literature, where an implicit rate-independency is assumed in both experimental and modelling propositions related to the biomechanics of the aortic and pulmonary valves. This study therefore creates a solid platform for future research in heart valve biomechanics with two important implications. First, experimental campaigns have to be carried out at high stretch rates; ideally as close to the physiological rate as possible. Second, new continuum/computational models are required to address the rate-dependent mechanical behaviour of the semilunar valves.

journal_name

Acta Biomater

journal_title

Acta biomaterialia

authors

Anssari-Benam A,Tseng YT,Holzapfel GA,Bucchi A

doi

10.1016/j.actbio.2019.02.008

subject

Has Abstract

pub_date

2019-04-01 00:00:00

pages

120-130

eissn

1742-7061

issn

1878-7568

pii

S1742-7061(19)30112-6

journal_volume

pub_type

杂志文章

在线工具

Rate-dependency of the mechanical behaviour of semilunar heart valves under biaxial deformation.