Thermal Stresses During Freezing of Biomaterials

在材料的全方位冻结期间，冻结的固体 外壳在表面形成，体积随之变化， 内部的冻结会导致外部的应力 壳这项研究的目的是量化这种 生物材料在阶段期间产生的热应力 在食品冷冻方面的变化。力学性能 冷冻材料的温度将被测量 使用专门制备的样品， 通过从一侧冻结来减小残余应力。应力 在典型的冻结过程中会观察到裂纹 在低温显微镜下观察到的开裂模式将是 相关的裂缝模式预测的一个合适的 失败理论这将是第一次定量分析 生物材料中的热应力，由于大体积 相变的变化。重要应用 包括冷冻食品中生物材料 加工，也用于冷冻外科和冷冻保存， 机关

During omni-directional freezing of a material, a frozen solid shell forms at the surface, and the volume changes associated with freezing of the interior causes stresses on the outer shell. The objectives of this study are to quantify such thermal stresses developed in a biomaterial during phase change in the context of food freezing. Mechanical properties of frozen materials will be measured in a temperature controlled Instron machine using samples specially prepared to minimize residual stresses, by freezing from one side. Stress cracks during typical freezing processes will be observed under a cryomicroscope. Observed cracking pattern will be correlated to fracture patterns predicted by a suitable failure theory. This will be the first quantitative analysis of thermal stresses in a biomaterial due to large volumetric changes from phase transformation. Important applications include not only freezing of biomaterials as in food processing but also in cryosurgery and cryopreservation of organs.