人工关节金属件表面激光冲击微造型的无菌性松动抑制机理

In order to solve the bottleneck problem about limited life span of joint prosthesis due to aseptic loosening, the mechanism of laser peen texturing (LPT) and the improvement on tribological performance of joint prosthesis will be investigated. Firstly, by conducting experimental and numerical investigation on the micro-dimple fabrication using LPT, the stress-strain relationship under the high strain rate effect of laser shock process and the mechanism of micro-dimple fabrication on joint prosthesis will be studied. Then, the influence of LPT process parameters on geometrical and physical property of joint prosthesis will be analyzed, with the consideration of comprehensive influences of high strain rate effect and plasma shielding effect. Followed, by analyzing and evaluating the results of friction and wear tests, the aseptic loosening inhibition mechanism of LPT will be revealed. Finally, the relationship between geometrical and physical property and the tribological performance of joint prosthesis will be established. Through the combination with the effect of LPT process parameters on geometrical and physical property of joint prosthesis, the process planning method of LPT aiming at inhibiting aseptic loosening of joint prosthesis will be proposed. The research will not only enrich the theory of friction and wear reduction using micro-dimple array, but also meet the urgent demand for prolonging the life span of joint prosthesis. It is also meaningful for expanding the application of LPT theoretically and practically.

针对人工关节因无菌性松动导致使用寿命受限的瓶颈问题，基于激光冲击微造型工艺，研究人工关节表面改形改性机理及微坑阵列对人工关节生物摩擦学性能的改善机制，实现抑制无菌性松动的目标。开展人工关节表面激光冲击微坑实验与仿真分析，研究激光高应变率动态冲击作用下材料应力应变状态的演变机制，阐明人工关节表面激光冲击微坑成形机理；探索在高应变率效应与等离子体屏蔽效应综合作用下，激光冲击工艺参数对人工关节材料表层几何与物理性能的影响规律；通过摩擦磨损实验分析与评价，揭示微坑阵列提高人工关节摩擦学性能进而抑制无菌性松动的内在机理；建立材料表层几何和物理性能与人工关节摩擦学性能间的映射关系，结合激光冲击微造型工艺规律，形成人工关节表面激光冲击微造型工艺规划方法。本项目的研究将丰富激光冲击微坑阵列的减摩抗磨理论，有望满足延长人工关节服役寿命的迫切需求，对于拓展激光冲击微造型技术的应用领域具有重要的理论和实用价值。

针对人工关节易于摩擦磨损从而导致无菌性松动失效的问题，基于激光冲击微造型加工新工艺，研究了人工关节表面激光冲击改形改性的机理与规律，旨在提高人工关节的摩擦磨损性能，延长其使用寿命。开展了典型人工关节材料表面激光冲击微造型试验与仿真建模，研究了在激光瞬时冲击作用下应力应变状态的演变机制，阐明了人工关节材料表面激光冲击微坑成形机理，探索了在高应变率效应与等离子体屏蔽效应下，激光冲击工艺参数对人工关节材料表层几何与物理性能的影响规律。研究发现，激光冲击后，人工关节材料表面和亚表面均产生了残余压应力、晶粒细化及硬度提高现象，且存在冲击饱和效应。通过数值仿真对激光冲击人工关节材料中出现的残余应力缺失现象进行了深入分析，建立了残余应力缺失的定量评价体系，研究了激光能量密度、光斑直径、脉冲宽度、压力分布方式等关键参数对残余应力缺失现象的影响机制，为抑制残余应力缺失现象提供了理论依据。通过模拟人体服役环境，对人工关节材料表面微坑阵列的摩擦学性能进行了分析，揭示了微坑阵列对于无菌性松动的抑制机理，得到了微坑直径、深径比、分布密度等特征参数与人工关节摩擦学性能间的映射关系。项目研究成果对于拓展激光冲击技术的应用领域、有效延长人工关节的使用寿命具有较高的理论和实用价值。