A novel tissue cutting apparatus was designed and fabricated, which was capable of setting up for different initial holding forces and tissue holding distances. Porcine aorta selected as a representative soft tissue was used in our cutting experiments. The measured force-displacement curves for all cases exhibit a characteristic pattern: a typical J-shaped curve is obtained before the blade cut into the tissue, once the blade breaks into the surface of the tissue, the cutting force suddenly reduces while crack is created and propagated quickly, then consequently the cutting force remains low and fluctuates. The tissue cutting process over one complete cutting cycle can be divided into three phases: deformation phase, rupture phase and cutting phase. Based on the energy balance in cutting process, the energy conversions were analyzed for each phase. The cutting force was modeled based on the energy balance. An exponential function was used to fit the cutting force in the deformation phase. The cutting force in rupture phase shows a linear decrease in a short time. The cutting force obtained with the model fits the experimental force curve well, which justifies the cutting force model.

自行设计和制造了一台可对切割力和刀具位移进行实时测量的生物软组织切割装置，并对猪主动脉壁组织开展了切割实验，对其切割特性进行了分析。切割力在组织未被切破之前随刀具位移非线性增大，呈典型的J形曲线关系;当切割力增大到一定程度时，组织被切破，切割力迅速减小;随后切割过程相对比较平稳，切割力在较小的范围内波动，呈现增大-减小的波浪形式。整个切割过程可被分为三个阶段：变形阶段、破裂阶段和切割阶段。根据能量平衡对切割过程中各个阶段能量之间的转换关系进行分析，并建立了各个切割阶段的切割力模型。在变形阶段，切割力表现为典型的非线性J形曲线关系，一个指数函数被用于拟合变形阶段的切割力;在切割阶段，根据能量平衡方程建立了切割力模型;而对于破裂阶段，由于时间非常短，切割力由破裂时的切割力直线减小。比较发现，模型所得切割力能够很好地与实验所得切割力吻合，证明切割力模型是正确的。

软组织, 断裂特性, 切割力, 主动脉