Knowing the mechanical properties of human adipose tissue is key to simulate surgeries such as liposuction, mammoplasty and many plastic surgeries in which the subcutaneous fat is present. One of the most important surgeries, for its incidence, is the breast reconstruction surgery that follows a mastectomy. In this case, achieving a deformed shape similar to the healthy breast is crucial. The reconstruction is most commonly made using autologous tissue, taken from the patient's abdomen. The amount of autologous tissue and its mechanical properties have a strong influence on the shape of the reconstructed breast. In this work, the viscoelastic mechanical properties of the human adipose tissue have been studied. Uniaxial compression stress relaxation tests were performed in adipose tissue specimens extracted from the human abdomen. Two different viscoelastic models were used to fit to the experimental tests: a quasi-linear viscoelastic (QLV) model and an internal variables viscoelastic (IVV) model; each one with four different hyperelastic strain energy density functions to characterise the elastic response: a 5-terms polynomial function, a first order Ogden function, an isotropic Gasser-Ogden-Holzapfel function and a combination of a neoHookean and an exponential function. The IVV model with the Ogden function was the best combination to fit the experimental tests. The viscoelastic properties are not important in the simulation of the static deformed shape of the breast, but they are needed in a relaxation test performed under finite strain rate, particularly, to derive the long-term behaviour (as time tends to infinity), needed to estimate the static deformed shape of the breast. The so obtained stiffness was compared with previous results given in the literature for adipose tissue of different regions, which exhibited a wide dispersion.

了解人体脂肪组织的机械特性是模拟手术的关键，例如抽脂，乳房成形术和许多存在皮下脂肪的整形手术。就其发生率而言，最重要的手术之一是乳房切除术后的乳房再造手术。在这种情况下，获得类似于健康乳房的变形形状至关重要。重建通常是使用从患者腹部获取的自体组织进行的。自体组织的数量及其机械性能对重建乳房的形状有很大影响。在这项工作中，已经研究了人类脂肪组织的粘弹性机械性能。在从人腹部提取的脂肪组织标本中进行了单轴压缩应力松弛测试。使用两种不同的粘弹性模型来拟合实验测试：准线性粘弹性（QLV）模型和内部变量粘弹性（IVV）模型；每个具有四个不同的超弹性应变能密度函数来表征弹性响应：5项多项式函数，一阶Ogden函数，各向同性Gasser-Ogden-Holzapfel函数以及neoHookean和指数函数的组合。具有Ogden功能的IVV模型是适合实验测试的最佳组合。粘弹性在模拟乳房的静态变形形状中并不重要，但是在有限应变率下进行的松弛测试中尤其需要使用它们，以得出长期行为（随着时间趋于无穷大），需要估计乳房的静态变形形状。将如此获得的刚度与文献中针对不同区域的脂肪组织的先前结果进行比较，该结果显示出较宽的分散性。