点阵夹芯结构非接触式损伤成像研究

Noncontact damage imaging method in lattice sandwich structures

针对点阵夹芯结构的脱焊等损伤问题,提出了基于高频动态响应的非接触式损伤成像技术,根据无基线损伤指标分析结构高频响应,实现脱焊损伤成像。数值仿真中,依据局部共振理论,以损伤区域低阶固有频率作为中心频率计算结构在声场激振下宽频段内振动响应,采用无基线损伤指标实现损伤成像,由损伤成像结果准确识别脱焊损伤位置;试验中,采用扬声器激振,扫描时激光测振系统进行全场振型拾取的非接触式试验测量方案,成功识别脱焊损伤的位置。验证了非接触式成像技术对点阵夹芯结构脱焊损伤检测的适用性与可行性,实现了无附加结构质量、无健康基准信号下的损伤识别。

Aiming at the damage problems such as debonding of lattice sandwich structure,a non-contact damage imaging technology based on high-frequency dynamic response is proposed.The high-frequency response of the structure is analysed according to the non-baseline damage index to realize debonding damage imaging.In the numerical simulation,based on the local resonance theory,the low-order natural frequency of the damage area is used as the centre frequency to calculate the response of the structure in a wide frequency range under sound field excitation,and the damage imaging is realized by using no baseline damage index.The damage imaging results can accurately identify the damage location;In the test,the non-contact test measurement scheme of using the loudspeaker to excite,and the laser vibration measurement system to pick up the full-field mode shape during scanning successfully identified the location of the debonding damage.The applicability and feasibility of the non-contact imaging technology for the damage detection of the dot matrix sandwich structure debonding is verified,and the damage identification without additional structural quality and without health reference signals is realized.