Remus Robin, Sure Christian, Selkmann Sascha, Uttich Eike, Bender Beate
Chair of Product Development, Department of Mechanical Engineering, Ruhr-University Bochum, Bochum, Germany.
Front Bioeng Biotechnol. 2024 May 24;12:1384062. doi: 10.3389/fbioe.2024.1384062. eCollection 2024.
Simulations of human-technology interaction in the context of product development require comprehensive knowledge of biomechanical behavior. To obtain this knowledge for the abdomen, we measured the continuous mechanical responses of the abdominal soft tissue of ten healthy participants in different lying positions anteriorly, laterally, and posteriorly under local compression depths of up to 30 mm. An experimental setup consisting of a mechatronic indenter with hemispherical tip and two time-of-flight (ToF) sensors for optical 3D displacement measurement of the surface was developed for this purpose. To account for the impact of muscle tone, experiments were conducted with both controlled activation and relaxation of the trunk muscles. Surface electromyography (sEMG) was used to monitor muscle activation levels. The obtained data sets comprise the continuous force-displacement data of six abdominal measurement regions, each synchronized with the local surface displacements resulting from the macro-indentation, and the bipolar sEMG signals at three key trunk muscles. We used inverse finite element analysis (FEA), to derive sets of nonlinear material parameters that numerically approximate the experimentally determined soft tissue behaviors. The physiological standard values obtained for all participants after data processing served as reference data. The mean stiffness of the abdomen was significantly different when the trunk muscles were activated or relaxed. No significant differences were found between the anterior-lateral measurement regions, with exception of those centered on the linea alba and centered on the muscle belly of the rectus abdominis below the intertubercular plane. The shapes and areas of deformation of the skin depended on the region and muscle activity. Using the hyperelastic Ogden model, we identified unique material parameter sets for all regions. Our findings confirmed that, in addition to the indenter force-displacement data, knowledge about tissue deformation is necessary to reliably determine unique material parameter sets using inverse FEA. The presented results can be used for finite element (FE) models of the abdomen, for example, in the context of orthopedic or biomedical product developments.
在产品开发背景下对人机交互进行模拟需要全面了解生物力学行为。为了获取腹部的这方面知识，我们测量了10名健康参与者在不同躺姿下（前位、侧位和后位）腹部软组织在高达30毫米的局部压缩深度下的连续力学响应。为此开发了一种实验装置，该装置由一个带有半球形尖端的机电压头和两个用于表面光学三维位移测量的飞行时间（ToF）传感器组成。为了考虑肌张力的影响，在躯干肌肉受控激活和放松两种状态下都进行了实验。使用表面肌电图（sEMG）来监测肌肉激活水平。获得的数据集包括六个腹部测量区域的连续力 - 位移数据，每个数据都与宏观压痕产生的局部表面位移同步，以及三个关键躯干肌肉处的双极sEMG信号。我们使用逆有限元分析（FEA）来推导一组非线性材料参数，这些参数在数值上近似实验确定的软组织行为。数据处理后为所有参与者获得的生理标准值用作参考数据。当躯干肌肉激活或放松时，腹部的平均刚度有显著差异。在前外侧测量区域之间未发现显著差异，但以白线为中心和以结节间平面下方腹直肌肌腹为中心的区域除外。皮肤变形的形状和面积取决于区域和肌肉活动。使用超弹性奥格登模型，我们为所有区域确定了独特的材料参数集。我们的研究结果证实，除了压头力 - 位移数据外，关于组织变形的知识对于使用逆有限元分析可靠地确定独特的材料参数集是必要的。所呈现的结果可用于腹部的有限元（FE）模型，例如在骨科或生物医学产品开发的背景下。
