基于角域信号重构及柔性聚焦的曲面多层结构超声检测方法

项目名称： 基于角域信号重构及柔性聚焦的曲面多层结构超声检测方法

项目编号： No.51205031

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 机械工程学科

项目作者： 胡宏伟

作者单位： 长沙理工大学

项目金额： 25万元

中文摘要： 具有轻质及高强度优点的曲面多层结构被广泛应用到关键设备上，有效检出其内部缺陷是保障设备运行安全的前提。本项目针对曲面多层结构超声无损检测时波形偏移、混迭和畸变等造成信号特征提取困难及成像分辨率低的问题，拟开展基于角域信号重构的超声特征提取方法及柔性聚焦成像理论的研究，包括：（1）研究超声在曲面多层结构中的传播特性，构建模块化多元高斯超声模型，探求角域回波信号特征变换规律，基于协整理论提出角域信号重构算法，实现各层回波和缺陷波的分离，准确提取曲面多层结构超声信号特征参数。（2）采用重构后的特征向量，设计自适应聚焦延时算法，研究合成孔径优化及聚焦点柔性规划方法，将平面匀质结构合成孔径聚焦提升至曲面多层结构的柔性聚焦，提高成像分辨率并降低计算复杂度。预期成果为揭示曲面多层结构超声信号特征变换机理、改进复杂结构的超声检测方法提供理论依据，对提高关键设备制造质量与服役寿命具有重要理论意义及应用价值。

中文关键词： 超声无损检测；角域信号重构；合成孔径聚焦技术；超声成像；曲面多层结构

英文摘要： Curved multilayer structures are widely used in key equipments due to their advantage of large strength-to-weight. To guarantee the application security,it is very important to inspect the internal defects. As result of waveform excursion,overlapping and distortion in ultrasonic inspection for the curved multilayer structures, the ultrasonic signal features are difficult to extract ,and moreover, the resolutin of ultrasonic imaging is low. To solve the problems, an ultrasonic feature extraction method based on an angular domain signal reconstruction and a flexible focusing imaging theory will be studied in this project. Firstly, the propagation characteristics of ultrasonic in the curved multilayer structure will be investigated. The modular multi-Gaussian ultrasonic model is proposed to research the transformation law of echo signals in the angular domain.The signal reconstruction algorithm in the angular domain will be established by the cointegration theory. Then the echoes and defect waves will be separated and the ultrasonic characteristic parameters of the curved multilayer structures will be accuratly extracted. Secondly, an adaptive delay algorithm considering the difference of geometry and the speed of sound will be proposed according to the reconstructed characteristic parameters. Subsequently, the sy

英文关键词： ultrasonic nondestructive testing；angular domain signal reconstruction；synthetic aperture focusing technology；ultrasonic imaging；curved multilayer structure