State sensing of composite structures with complex curved surface based on distributed optical fiber sensor

Abstract

Composite structures with complex curved surface are typical important external structures of aircraft. Residual strain will be formed due to complex manufacturing processes, resulting in the weakness of structural strength. In addition, there are great security implications that various mechanisms used for aircraft safety may cause failures on service, such as fiber fracture, matrix cracking, stratification, and debonding. In this article, methods of structural state sensing on composite structures with complex curved surface are researched. This article established a method of strain monitoring on composite structures and strategy of damage identification based on distributed optical fiber sensors. First, strategies of high spatial resolution strain measurement are studied, and the criteria of damage identification on composite laminates based on strain information are deduced, which could be used on accurate positioning of crack tips. Finally, strain measurement and damage identification tests of composite structures with complex curved surface under uniform load condition were conducted. The results indicate that the distributed optical fiber sensor installed on the composite structures with complex curved surface can be used to measure strain precisely and identify damage in the neighborhood of fiber installation path accurately.

Improved Kalman Filtering-Based Information Fusion for Crack Monitoring Using Piezoelectric-Fiber Hybrid Sensor Network

“…Optical fiber sensor monitoring is to judge the damage state of the structure according to the change of strain field and its correlation with the damage. The damage near the actuator-sensor path of the optical fiber sensor can be determined by accurate strain field measurement (Shan et al, 2019). The location and severity of damage can be determined by comparing the signal differences of optical fiber sensing before and after the damage.…”

Structural Damage Identification Based on Integrated Utilization of Inverse Finite Element Method and Pseudo-Excitation Approach

“…The fiber Bragg grating (FBG) sensor network has already become a common option in SHM, thanking to its inclusion of a large number of sensors and its capacity for a fast response [ 42 , 43 , 44 ]. On the other hand, distributed optical fiber sensors are receiving increasing attention due to their appealing potential in dense measurement of strains [ 45 , 46 , 47 ]. The number of measurement points can easily reach the hundreds or even thousands by using a single distributed optical fiber, and the response frequencies of these sensors are under rapid yearly increase.…”

Distributed Fibre Optic Sensor-Based Continuous Strain Measurement along Semicircular Paths Using Strain Transformation Approach

“…Among all the structural parameters, strain can be considered as an important parameter, which can be utilised for SHM. Measuring strains on a structure has two advantages: firstly, strain directly reflects the deformation behaviour of a structure under loading, and secondly, strain is linked to the stress field, thereby any changes to a material stress field implies a change in the strain field [ 10 , 11 ]. Currently, surface strains on a structure are usually measured using foil strain gauges (FSG)/strain rosettes (SR), which are considered as a mature technology.…”

“…Due to superior sensing capabilities, DFOSs are gaining popularity among the research and industrial communities for sensing applications on various types of structures [ 21 ]. Shan et al [ 10 ] employed DFOSs for monitoring strains on a complex curved composite structure. Distributed strain sensing along a high-performance composite hydrofoil with embedded DFOSs was performed by Maung et al [ 12 ].…”