An Identification of Collapse Defect in Fiber Optic Winding Structure Based on Distributed Stress Testing

This article presents a new method for defect identification in fiber optic winding structures. Compared with traditional machine vision and X-ray methods, the identification method based on the stress characteristics of defects is not affected by fiber size and the external environment. In theory, we quantitatively calculated the stress reduction and transmission characteristics of collapse defect by stress analysis. In experiment, we constructed collapse defects by adding a plastic layer to the mandrel in the winding structure. The test results of BOTDA at a high spatial resolution of 5 cm are consistent with the theory, revealing that the collapse defect would reduce stress and be transmitted in two adjacent layers. This method identifies collapse defects rapidly and accurately, which is essential for improving the quality of the winding structure and reducing dynamic release failure.