Measuring the mechanical properties of soft biological tissues in-vitro by using conventional methods (e.g. tension, compression, or indentation) is prone to external testing and sample preparation factors. For example, sample slippage affects the measurement accuracy of mechanical properties of soft biological tissues. In addition, samples have to go through a complex cutting process to be prepared in specific shapes, which increases the post-mortem time spent before testing. The purpose of this study is to investigate the capability of a new technique to measure the mechanics of soft biological tissues without experiencing the conventional challenges. It measures the mechanical behavior of soft materials by introducing and expanding spherical cavity deformations within materials’ internal structure while generating two stresses simultaneously, radial and hoop stresses. Two porcine livers were tested. The experimental data were used to calibrate the material parameters of three hyperelastic models, namely: Yeoh, Arruda-Boyce, and Ogden. Numerical simulations were performed to validate the material parameters. Also, Computed Tomography (CT) imaging technology was used to verify the configuration of the cavity deformations. The outcome of the numerical simulations showed that hyperelastic models were able to predict the material response to cavity loading. In addition, CT imaging confirmed the spherical configuration of the applied deformations. From the experimental results, numerical simulations and the CT imaging, it can be concluded that the cavity expansion test is capable of measuring the mechanics of soft biological tissues without experiencing the difficulties encountered in conventional techniques.

中文翻译：

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使用受控空化流变学在体外测量猪肝组织的超弹性反应

使用常规方法（例如拉伸、压缩或压痕）在体外测量软生物组织的机械性能容易受到外部测试和样品制备因素的影响。例如，样品滑动会影响软生物组织机械性能的测量精度。此外，样品必须经过复杂的切割过程才能制成特定的形状，这增加了测试前的验尸时间。本研究的目的是研究一种新技术在不经历传统挑战的情况下测量软生物组织力学的能力。它通过在材料内部结构中引入和扩展球腔变形，同时产生两个应力来测量软材料的机械性能，径向和环向应力。测试了两个猪肝。实验数据用于校准三个超弹性模型的材料参数，即：Yeoh、Arruda-Boyce 和 Ogden。进行了数值模拟以验证材料参数。此外，计算机断层扫描 (CT) 成像技术用于验证腔变形的配置。数值模拟的结果表明，超弹性模型能够预测材料对腔体载荷的响应。此外，CT 成像证实了应用变形的球形配置。从实验结果、数值模拟和CT成像来看，