Care & Health Applications, Philips Research, Eindhoven, The Netherlands.
J Biomech. 2010 Apr 19;43(6):1153-9. doi: 10.1016/j.jbiomech.2009.11.037. Epub 2010 Feb 19.
Although subcutaneous adipose tissue undergoes large deformations on a daily basis, there is no adequate mechanical model to describe the transfer of mechanical load from the skin throughout the tissue to deeper layers. In order to develop such a non-linear model, a set of experimental data is required. Accordingly, this study examines the long term behavior of adipose tissue under small strain and its response to various large strain profiles. The results show that the shear modulus dramatically increases to about an order of magnitude after a loading period between 250 and 1250 s, but returns to its initial value within 3 h of recovery from loading. In addition, it was observed that the stress-strain responses for various large strain history sequences are reproducible up to a strain of 0.15. For increasing strains, the stress decreases for subsequent loading cycles and, above 0.3 strain, tissue structure changes such that the stress becomes independent of the applied strain. From the results, it can be concluded that adipose tissue likely behaves as an (anti-) thixotropic material and that a Mooney-Rivlin model might be appropriate to simulate behavior at physiologically relevant high strains. However, before the model is developed more fully, further experimental research is needed to ratify that the material is (anti-)thixotropic.
尽管皮下脂肪组织每天都会发生较大的变形，但目前仍没有合适的力学模型可以描述从皮肤到深层组织的机械载荷传递。为了开发这样的非线性模型，需要一组实验数据。因此，本研究考察了脂肪组织在小应变下的长期行为及其对各种大应变轮廓的响应。结果表明，在 250 到 1250 秒的加载期间，剪切模量急剧增加到大约一个数量级，但在加载恢复 3 小时内恢复到初始值。此外，观察到各种大应变历史序列的应力-应变响应在 0.15 应变以内是可重复的。对于增加的应变，随后的加载循环中的应力减小，并且在 0.3 应变以上，组织结构发生变化，使得应力变得不依赖于施加的应变。从结果可以得出结论，脂肪组织可能表现为（反）触变材料，并且莫尼-里夫林模型可能适合模拟生理相关高应变下的行为。然而，在更全面地开发模型之前，需要进一步的实验研究来证实该材料是（反）触变的。
