冲击力作用下种植体周围骨动态力学响应的数值模拟

Dynamic Mechanical Response of the Peri-Implant Bone Structure Subjected to Impact Load:A Numerical Study

目的研究种植体周围骨结构在冲击力作用下的动态力学响应和损伤特征。方法建立种植体周围骨微观结构的有限元模型,对刚体施加初始速度模拟冲击加载,采用应力失效准则,编写用户材料子程序对模型进行失效判断,分析冲击力作用下骨结构的应力变化及损伤状况。结果冲击力作用后,皮质骨应力迅速达到峰值(16.01 MPa),而种植体底端骨小梁应力值在冲击后0.1μs达到应力峰值(5.85 MPa);冲击作用会形成应力波在骨结构内传播,骨结构损伤随时间发生变化;冲击能量可被骨小梁通过变形而缓冲和耗散,骨小梁应力达到屈服极限后出现损伤和破坏,而皮质骨在冲击作用下未出现损伤破坏。结论对于冲击损伤患者,应更加重视骨小梁的结构变化。所建数值模型能将骨的结构力学性能和自身几何特性结合,较好预测骨的冲击损伤情况。研究结果可为临床承受冲击损伤患者损伤评估和损伤后治疗提供参考。

Objective To investigate the dynamic mechanical responses and damage characteristics of periimplant bone structures subjected to impact load.Methods A finite element model of the peri-implant bone microstructure was established,and an initial velocity was applied to the rigid body to simulate the impact load.A stress failure criterion was employed and a user-material subroutine was developed to assess failure.Subsequently,bone damage after the impact load was analyzed according to the material subroutine.Results After the impact load,the stress on the cortical bone increased rapidly,reaching a peak value(16.01 MPa)immediately.In contrast,the stress on the trabecular bone at the bottom of the implant reached its peak value(5.85 MPa)at 0.1μs.The impact load resulted in stress waves that propagated and diffused within the bone structure,causing changes in the bone structure damage over time.The generated impact energy could be absorbed and dissipated by the trabecular bone through deformation.The deformed trabecular bone experienced damage and failure upon reaching the yield limit,whereas the cortical bone did not experience damage or failure under an impact load.Conclusions Structural changes in the trabecular bone should be considered in patients with impact damage.The numerical model established in this study can effectively predict bone impact damage 718 by combining the structural mechanical properties and geometric characteristics of the bones.These findings can serve as a reference for assessing bone damage and post-damage treatment in patients subjected to impact loads in clinical practice.