Objective: This work evaluates the rate-dependent and relaxation properties of native porcine heart valves, glutaraldehyde fixed porcine pericardium, and decellularized sterilized porcine pericardium. Methods: Biaxial tension testing was performed at strain-rates of 0.001 s ⁻¹ , 0.01 s ⁻¹ , 0.1 s ⁻¹ , and 1 s ⁻¹ . Finally, relaxation testing for 300 s was performed on all heart valve biomaterials. Results: No notable rate-dependent response was observed for any of the three biomaterials with few significant differences between any strain-rates. For relaxation testing, native tissues showed the most pronounced drop in stress and glutaraldehyde the lowest drop in stress although no tissues showed anisotropy in the relaxation. Conclusions: Increasing the strain-rate of the three biomaterials considered does not increase the stress within the tissue. This indicates that there will not be increased fatigue from accelerated wear testing compared to loading at physiological strain-rates as the increase strain-rates would likely not significantly alter the tissue stress.

中文翻译：

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猪主动脉瓣生物材料的频率依赖性和松弛特性

客观的：这项工作评估了天然猪心脏瓣膜、戊二醛固定猪心包和去细胞灭菌猪心包的速率依赖性和松弛特性。方法：双轴拉伸测试在 0.001 s ^-1 、0.01 s ^-1 、0.1 s ^-1 和 1 s ^-1的应变速率下进行 。最后，对所有心脏瓣膜生物材料进行 300 秒的松弛测试。结果：对于这三种生物材料中的任何一种，都没有观察到显着的速率依赖性响应，任何应变率之间几乎没有显着差异。对于松弛测试，天然组织显示出最显着的应力下降，而戊二醛的应力下降最低，尽管没有组织在松弛中显示出各向异性。结论：增加所考虑的三种生物材料的应变率不会增加组织内的应力。这表明与生理应变率加载相比，加速磨损测试不会增加疲劳，因为增加的应变率可能不会显着改变组织应力。