Application of low-coherence interferometry for in situ nondestructive evaluation of thin and thick multilayered transparent composites

作者：Khomenko Anton^*; Cloud Gary Lee; Haq Mahmoodul

来源：Optical Engineering, 2015, 54(12): 125103.

DOI：10.1117/1.OE.54.12.125103

• nondestructive evaluation
• multilayered transparent composite
• delamination
• low-coherence interferometry
• laser diode
• femtosecond laser

Multilayered transparent composites having laminates with polymer interlayers and backing sheets are commonly used in a wide range of applications where visibility, transparency, impact resistance, and safety are essential. Manufacturing flaws or damage during operation can seriously compromise both safety and performance. Most fabrication defects are not discernible until after the entire multilayered transparent composite assembly has been completed, and in-the-field inspection for damage is a problem not yet solved. A robust and reliable nondestructive evaluation (NDE) technique is needed to evaluate structural integrity and identify defects that result from manufacturing issues as well as in-service damage arising from extreme environmental conditions in addition to normal mechanical and thermal loads. Current optical techniques have limited applicability for NDE of such structures. This work presents a technique that employs a modified interferometer utilizing a laser diode or femtosecond fiber laser source to acquire in situ defect depth location inside a thin or thick multilayered transparent composite, respectively. The technique successfully located various defects inside examined composites. The results show great potential of the technique for defect detection, location, and identification in multilayered transparent composites.

• 出版日期2015-12