A model-based measurement procedure for the characterization of frequency-dependent material properties of piezoceramics using a singleton specimen

基于模型的测量程序，用于使用单个样本表征压电陶瓷的频率相关材料特性

• 批准号: 321120716
• 负责人: Professor Dr.-Ing. Bernd Henning
• 金额: --
• 依托单位: Institut für Mathematik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/321120716?language=en
• 关键词: model; based; measurement; procedure; characterization

The increasingly simulation-based design processes of ultrasonic transducers require the best possible descriptions of the used materials for realistic results.Piezoceramic materials can be modeled using at least 10 parameters.The determination of these parameters is done according to current standards using the evaluation of resonance frequencies of different specimen geometries.However, since these different specimens are always subject to different process and polarization conditions, implausible or inconsistent parameter sets can result when the individual material parameters are combined.The characterisation of a piezoceramic on a single specimen is difficult, since there are usually no sufficiently high sensitivities for all relevant parameters.An increase of the sensitivities and thus a determination of a complete material parameter set was realised with an optimised electrode topology on piezoceramic disks in the previous project.Since the more complex electrode structure can no longer be represented by analytical approximations, the material parameters are determined by an inverse method.In the process, a digital twin is created in the form of a finite element method model, which contains the material parameters as input variables.Problem-adapted optimisation algorithms can then be used to influence the material parameters of the model in such a way that the behaviour of the real system is mirrored as well as possible.However, several impedance measurements on a piezoceramic disc are currently necessary for this.A more dynamic mathematical optimisation of the electrode topology should reduce this to a single measurement.In addition, a causal damping model is to be found which better maps the physical material behaviour and thus results in a more realistic simulation.Again, a reliable solution to the inverse problem must be ensured by sufficiently large sensitivities.

超声换能器的设计过程越来越多地基于仿真，因此需要对所用材料进行最佳描述，以获得逼真的结果。压电陶瓷材料可以使用至少10个参数进行建模。这些参数的确定是根据当前标准通过评估不同试样几何形状的谐振频率来完成的。然而，由于这些不同的样品总是经受不同的工艺和极化条件，当各个材料参数组合时，可能导致不可信的或不一致的参数集。在单个样品上表征压电陶瓷是困难的，因为对于所有相关参数通常没有足够高的灵敏度。在以前的项目中，通过压电陶瓷盘上的优化电极拓扑结构实现了灵敏度的增加，从而确定了完整的材料参数集。由于更复杂的电极结构不再能用解析近似表示，因此材料参数通过逆方法确定。在此过程中，以有限元方法模型的形式创建数字孪生模型，该模型包含作为输入变量的材料参数。然后可以使用问题适应的优化算法来影响模型的材料参数，使得尽可能好地反映真实的系统的行为。然而，为此，目前需要在压电陶瓷盘上进行几次阻抗测量，电极布局的更动态的数学优化应该将其减少到单个测量。另外，要找到一个因果阻尼模型，它能更好地反映材料的物理特性，从而得到更真实的模拟结果。2同样，必须通过足够大的灵敏度来确保反问题的可靠解。