Nonlinear time series analysis using Bayesian recurrence plot quantification to analyse the dynamics of friction-induced vibrations, in particular wear and damping in artificial synovial joints.

使用贝叶斯递归图量化的非线性时间序列分析来分析摩擦引起的振动的动力学，特别是人工滑膜关节中的磨损和阻尼。

• 批准号: 314996946
• 负责人: Dr. Sebastian Oberst
• 金额: --
• 依托单位: Institut für Strukturdynamik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/314996946?language=en
• 关键词: Nonlinear; time; series; analysis; using

Unwanted vibrations particularly owing to friction are encountered in various industries. While vibrations usually decay with time owing to damping, friction-induced instabilities cause positive and energy providing positive system damping. Positive damping lets vibration amplitudes grow, leading to excessive wear and premature product failure. These positive feedback loops, once established, also lead to audible noises, which are also problematic in artificial synovial joints, as found in total knee or hip replacements. In the past most research concentrated on reducing wear particles or improving their biocompatibility using experimental testing. However, damping and lubrication considering the cartilage or synovial fluid and their effect on artificial synovial joints friction has never been studied numerically or from the dynamics point of view. Here, nonlinear dynamics as output quantity is employed to develop highly innovative Bayesian recurrence plot quantification analysis measures based on recurrence plots and Bayesian updating in combination with the Maximum Entropy Theory. Dynamic variants with credibility bounds, embedding parameters, and unstable periodic orbits are estimated. Attractor-based templates are used to generate inversely reduced-order models to explore the nonlinear dynamics. The basin of attraction and its linear stability boundary is estimated using the templates and analytical models. The influence of noise on invariant estimations in practical measurements is considered. This novel methodology is applied to nonlinear benchmark systems and then to a large database of experimental biomechanical tests of hip and knee implants, considering different driving parameters, various lubricants and running times. By using sophisticated vibration testing over laser vibrometry and kinematics determined over Roentgen stereo photogrammetric analysis, in a bottom up process, a high-fidelity finite element model coupled to computational fluid dynamics simulations is setup to study artificial synovial hip joint with focus on lubrication and squeeze film damping considering the synovial fluid. Modern methods of uncertain parameter identification are employed taking into account the component, the subassembly and the assembly level with and without fluid. Numerical time traces are then analysed by applying the novel Bayesian recurrence plot quantification measures and invariant estimations which allow the numerical model being further updated, both evidence- and response-based and in a top-down approach. Different stages according to the gate cycle are analysed rendering the model updating as a multi-stage process and allow finally to study the effect of the synovial fluids thin film on damping and dissipation. Findings will lead to significant insights of underlying the physics in friction and wear in artificial synovial joints which can be used to design quieter hip inserts by making use of optimised thin film or squeeze film damping.

在各种工业中会遇到特别是由于摩擦引起的不必要的振动。虽然振动通常由于阻尼而随时间衰减，但摩擦引起的不稳定性引起正能量，提供正系统阻尼。正阻尼使振动幅度增大，导致过度磨损和产品过早失效。这些正反馈回路一旦建立，也会导致可听噪声，这在人工滑膜关节中也是有问题的，如在全膝关节或髋关节置换中发现的。在过去，大多数研究集中在减少磨损颗粒或通过实验测试改善其生物相容性。然而，考虑软骨或滑液的阻尼和润滑及其对人工滑膜关节摩擦的影响从来没有被数值研究或从动力学的角度来看。在这里，非线性动力学作为输出量，开发高度创新的贝叶斯递归图量化分析措施的基础上，递归图和贝叶斯更新结合最大熵理论。动态变量的可信界，嵌入参数，和不稳定的周期轨道估计。基于吸引子的模板用于生成逆降阶模型，以探索非线性动力学。使用模板和分析模型估计吸引域及其线性稳定边界。考虑了实际测量中噪声对不变估计的影响。这种新的方法被应用到非线性基准系统，然后到一个大型数据库的髋关节和膝关节植入物的实验生物力学测试，考虑不同的驱动参数，各种润滑剂和运行时间。通过使用激光测振仪和X线体视摄影测量分析确定的运动学的复杂的振动测试，在自下而上的过程中，高保真有限元模型耦合到计算流体动力学模拟被设置为研究人工髋关节滑膜，重点是考虑滑液的润滑和挤压膜阻尼。采用现代不确定性参数识别方法，考虑到组件，子组件和装配水平的流体和无流体。然后，通过应用新的贝叶斯递归图量化措施和不变估计，允许数值模型进一步更新，证据和响应为基础，并在自上而下的方法进行分析的数值时间轨迹。根据门周期的不同阶段进行了分析，渲染模型更新作为一个多阶段的过程，并允许最后研究的滑液薄膜的阻尼和耗散的效果。研究结果将导致对人工滑膜关节中摩擦和磨损的物理学基础的重要见解，这些物理学基础可用于通过利用优化的薄膜或挤压膜阻尼来设计更安静的髋关节插入物。