飞行器增压输送管路损伤的超声导波定量评估技术

The ultrasonic guided wave (UGW) has several advantages of less attenuation and longer distance on the propagation path than conventional non-destructive testing methods. It can monitor the pipelines in a wide range and full length. Hence, UGW has potential values on the defect assessment for pipes in the pressurization and propellant feed system of aircrafts. This project intends to study the propagation mechanism of UGW in the heterogeneous interfaces of pipelines, then to explore the energy changes of UGW at defects of pipelines and the impact of the reflection and transmission coefficients of UGW caused by different defect forms. The defect model for pipelines is built, the dispersion of UGW modes are studied by using an arbitrary incident UGW modes. The construction methods of customized multiwavelets are studied meet the convergence conditions when multiwavelets econstruction, the multi-objective optimization method is used to construct multiwavelets matching the defect features. Hence, the defect features can be extracted accurately. Several appropriate criteria are set and selected to obtain the quantitative assessment of pipeline defects. The tests of pipelines in the pressurization and propellant feed system are carried to verify the correctness of the proposed quantitative assessment methods. This project supplies the effective methods for the fault prognosis and health assessment for the pipelines in the pressurization and propellant feed system of aircrafts, then to ensure the safe operation of the space launch vehicles.

超声导波具有在传播路径上的能量衰减小，传播距离远，可以实现大范围、全方位管路监测的优点，在航天飞行器增压输送管路监测领域具有巨大的潜在应用价值。本项目拟研究超声导波在增压输送管路异质界面处的传播机理，探索管路损伤处超声导波能量的变化、缺陷形式对超声导波反射和透射系数的影响；建立管路损伤模型，研究当管路出现损伤时由任意模态导波入射时导波模态的散射机理；研究自适应多小波构造方法，使其满足多小波函数重构时的收敛性条件，利用多目标优化方法构造出与特征匹配的优化多小波基函数，实现管路损伤特征的准确提取；设置并优选合适的损伤程度判定准则，将损伤特征进行归一化处理，实现管路损伤的定量评估。开展增压输送管路试验，验证定量评估方法的正确性。本项目为飞行器增压输送管路系统故障预示与运行安全评估提供有效的分析手段，确保航天运载器的运行安全。

超声导波具有在传播路径上的能量衰减小，传播距离远，可以实现大范围、全方位管路监测的优点，在航天飞行器增压输送管路监测领域具有巨大的潜在应用价值。本项目建立了增压输送管路损伤和管路异质界面模型，研究了超声导波在管路损伤和异质界面耦合中传播机理；研究了多小波自适应阈值降噪算法，有效消除噪声干扰，突出信号中的微弱损伤特征，准确提取出管路的早期损伤特征；研究了自适应多小波函数构造方法，构造出与故障特征匹配的优化多小波基函数，提高了管路损伤特征提取的准确度；研究了自适应稀疏解卷积算法，实现了管路裂纹损伤的准确定位；研究了超声导波频散信号处理方法，建立了反映信号损伤因子与缺陷深度信息关系的超声导波管道层析成像二维声学模型；构建并优选合适的损伤程度判定准则，将故障特征进行归一化处理，实现损伤的定量评估。开展增压输送管路试验，验证定量评估方法的正确性。本项目为飞行器增压输送管路系统故障预示与运行安全评估提供有效的分析手段，确保航天运载器的运行安全。