微细观尺度下材料蠕变行为的非线性兰姆波评价理论与表征方法

项目名称： 微细观尺度下材料蠕变行为的非线性兰姆波评价理论与表征方法

项目编号： No.11474093

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 项延训

作者单位： 华东理工大学

项目金额： 92万元

中文摘要： 在石油化工、电力、核电、航空发动机等重要工业领域中广泛存在高温下运行服役的核心构件，其服役过程中的蠕变损伤是威胁设备安全运行的重要因素。本项目针对微细观尺度下材料的蠕变行为，发展和完善非线性超声Lamb波的评价理论和表征方法。通过研究基频Lamb波模式传播过程中转入二次谐波的能量流密度来选择和优化非线性Lamb波激发模式；构建蠕变全过程状态下包括共格析出相、非共格析出相以及微孔洞等材料微观组织演化和非线性Lamb波之间相互作用的评价理论；从微观角度研究材料不同蠕变行为对非线性Lamb波传播的影响，并开展有限元仿真计算模拟非线性Lamb波在不同蠕变试样中传播特性的研究；最后利用理论模型计算、有限元仿真计算、实验测量数据，基于唯象方法构建非线性Lamb波-微观组织-结构完整性（剩余寿命）三者相关的表征方法。本项目的研究将发展非线性Lamb波表征材料蠕变损伤及剩余寿命预测的新的超声检测技术。

中文关键词： 超声兰姆波；二次谐波；蠕变行为；金属材料；无损评价

英文摘要： The key components applied in petrochemical industry, power plants, nuclear power and aeroengine are usually subjected to high-temperature exposure and then undergo degradation of strength due to creep damage, which would be a potential threat to the safety of equipment operation. The current project aims to investigate a new nondestructive evaluation method using nonlinear Lamb waves for characterizing the creep behaviors in materials with micro- and meso-scale structure evolution. First, the selection and optimization of nonlinear Lamb wave excitation mode can be determined by studying the energy flow density transferring from the fundamental Lamb wave to the second-harmonics during wave propagation. An analytical model of the interaction between the nonlinear Lamb wave and microstructure evolution is proposed for characterizing creep behavior including coherency precipitation, non-coherency precipitation and micro-void. Then, the influences of different creep behaviors on nonlinear Lamb wave propagation are interpreted in the perspective of microstructure evolution analysis. The finite element method (FEM) simulation is carried out to investigate the features of nonlinear Lamb waves propagating in various crept specimens. Finally, based on phenomenological research, an evaluation method relating to nonlinear Lamb wave-microstructures-structure integrity (residual life) could be established by analytical model computations, FEM simulations and experimental measurements. The researches of this project would provide a potential new ultrasonic testing technology for creep damage and residual life prediction of materials using the nonlinearity of Lamb waves.

英文关键词： Lamb wave;second-harmonic;creep behavior;metallic material;nondestructive evaluation