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应用ANSYS/LS-DYNA软件,对聚乳酸(PLA/)热塑性聚氨酯(TPU)生物材料受冲击载荷作用下的界面应力分布进行了有限元模拟。结果表明:PLA树脂与TPU之间界面的Y方向正应力、XZ剪切应力以及Von Mises等效应力均在靠近弹性粒子赤道处达到最大值,然后朝极点方向逐渐减小,于极点附近达到最小值;但是界面Y、Z方向的正应力分布情况正好相反,其中Y方向正应力在冲击过程中对共混物界面的影响大于Z方向正应力。PLA/TPU共混物韧性的增加主要是由于界面处应力集中,令弹性体粒子发生大的形变而引发大量银纹以,及界面附近树脂的塑性形变,吸收大量的冲击能量所致。
The ANSYS / LS-DYNA software was used to simulate the interface stress distribution of PLA / TPU biomaterials under impact load. The results show that the normal stress in the Y direction, the XZ shear stress and the Von Mises equivalent stress at the interface between the PLA resin and the TPU reach the maximum near the elastic particle equator and then decrease toward the pole and reach the minimum around the pole However, the normal stress distribution in the Y and Z directions is just the opposite, and the normal stress in the Y direction affects the blend interface more than the Z stress in the impact process. The increase of ductility of PLA / TPU blends is mainly due to the stress concentration at the interface, causing a large deformation of the elastomer particles and causing a large number of silver fringes and the plastic deformation of the resin near the interface, resulting in absorption of a large amount of impact energy.