Complex distributions of residual stress and strain in the mouse left ventricle: experimental and theoretical models
Complex distributions of residual stress and strain in the mouse left ventricle: experimental and theoretical models
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DOI：
10.1007/s10237-002-0021-0
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发表时间：
2003-04-01
影响因子：
3.5
通讯作者：
Criscione, J. C.
中科院分区：
文献类型：
--
作者：
Omens, J. H.;McCulloch, A. D.;Criscione, J. C.
当去除所有外部载荷时，大多数软生物组织（包括心室心肌）并不是无应力的。残余应力对心脏的机械性能有影响，并且可能是区域生长和重构模式的指标。当进行径向切割时（初始平均张开角为64 +/- 17度），停搏心室的横截面环张开，但进一步的周向切割显示，随着环的进一步张开，组织中存在额外的残余应力。在正常小鼠心脏中，短轴环的内半部分比外半部分打开更多，并且这种变化依赖于尖基部位置。在顶点处，内部部分与外部部分的开口角度为226 +/- 47度与89 +/- 28度，而在基部处，相同的两个角度为160 +/- 30度与123 +/- 35度。在切削实验的基础上，采用一个简单的理论圆柱壳模型和不可压缩的超弹性材料特性来模拟实验变形。该模型预测不同的残余应力场取决于在周向切割后的开口的性质（这是在常规径向切割后完成的）。观察到的开口角是一致的，与那些预测相比，如果第一次切割，以消除所有的残余应力附近的内牙的陡峭的应力梯度。这些结果意味着一个更复杂的分布在心室肌的残余应力和应变比以前认为的。
Most soft biological tissues, including ventricular myocardium, are not stress free when all external loads are removed. Residual stress has implications for mechanical performance of the heart, and may be an indicator of patterns of regional growth and remodeling. Cross-sectional rings of arrested ventricles opened up when a radial cut was made (initial mean opening angles were 64 +/- 17 degrees), but further circumferential cuts revealed the presence of additional residual stresses in the tissue with further opening of the rings. In normal mouse hearts, the inner half of a short-axis ring opened more than the outer half, and this change was dependent on apex-base location. At the apex the inner section vs. outer section opening angles were 226 +/- 47 degrees vs. 89 +/- 28 degrees, while at the base the same two angles were 160 +/- 30 degrees vs. 123 +/- 35 degrees. A simple theoretical cylindrical shell model with incompressible hyperelastic material properties was used to model the experimental deformations based on the cutting experiments. The model predicts different residual stress fields depending on the nature of the opening after the circumferential cut (which is done after the conventional radial cut). The observed opening angles were consistent with steep stress gradients near the endocardium compared with those predicted if the first cut was assumed to relieve all residual stresses. These results imply a more complex distribution of residual stress and strain in ventricular myocardium than previously thought.