Barely visible impact damage detection for composite sandwich structures by optical-fiber-based distributed strain measurement
Barely visible impact damage detection for composite sandwich structures by optical-fiber-based distributed strain measurement
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DOI：
10.1088/0964-1726/18/8/085018
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发表时间：
2009-08-01
影响因子：
4.1
通讯作者：
Takeda, N.
中科院分区：
文献类型：
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作者：
Minakuchi, S.;Okabe, Y.;Takeda, N.
作者开发了一种用于大型复合材料夹层结构的冲击损伤检测系统，该系统使用贯穿整个结构的光纤网络。利用高空间分辨率的布里渊传感系统（前泵浦脉冲布里渊光时域分析（PPP-BOTDA））进行分布式应变测量。PPP-BOTDA传感系统可以通过采用受激布里渊散射来测量沿光纤的沿着轴向应变。该系统实现了10厘米的空间分辨率，5厘米的采样间隔，超过1公里的传感范围。我们之前的研究表明，厘米空间分辨率内的非均匀轴向应变加宽了布里渊增益谱的宽度，这是PPP-BOTDA的输出。PPP-BOTDA的特定响应被用来检测受损区域中沿残余疲劳凹痕沿着的非均匀应变分布。首先，光纤传感器网络的响应，形成在粘合剂层，进行了模拟，以澄清所提出的损伤检测技术的有效性和局限性。最后通过实验对该系统进行了验证。随着损伤的增大，布里渊增益谱的宽度变宽。因此，可以估计几乎看不见的损坏的位置和大小。该系统的开发是非常有用的首次检测大型夹层结构在航空航天和海洋应用。
The authors developed an impact damage-detection system for large-scale composite sandwich structures using an optical fiber network running throughout the structure. A Brillouin-based sensing system with high spatial resolution (pre-pump pulse Brillouin optical time-domain analysis (PPP-BOTDA)) was utilized for distributed strain measurement. The PPP-BOTDA sensing system can measure axial strain along the optical fiber by employing stimulated Brillouin scattering. The system realizes a spatial resolution of 10 cm, a sampling interval of 5 cm, and a sensing range of more than 1 km. Our previous study revealed that a non-uniform axial strain within centimeter spatial resolution broadens the width of the Brillouin gain spectrum, which is the output of the PPP-BOTDA. The specific response of the PPP-BOTDA was employed to detect non-uniform strain distribution along a residual facesheet dent in a damaged area. First, the response of the optical fiber sensor network, formed in the adhesive layer, was simulated to clarify the effectiveness and limitations of the proposed damage-detection technique. The system was then validated by an experiment. As the damage became larger, the width of the Brillouin gain spectra became broader. Consequently, the location and size of barely visible damage could be estimated. The system developed is quite useful for a first inspection of large-scale sandwich structures in aerospace and marine applications.