Features of creating a system of simultaneous built-in testing of deformation and temperature of composite structures by fiber-optic sensors

This article describes the relevance of improving existing and creating new effective methods of non-destructive testing and technical diagnostics of highly loaded aircraft structures made of polymer composite materials to ensure safe operation. Approaches to the creation of efficient systems for the simultaneous embedded testing of deformations and temperature of structures made of polymer composite materials by an optical method using embedded fiber-optic sensors based on fiber Bragg gratings are considered. The world experience in creating such systems, the methodology of non-destructive testing are analyzed, taking into account the creation of a spatial topology of fiber-optic sensors in a real product. It is shown that to solve this problem, it is most expedient to use the method of two optical fibers with different sensitivity to deformation and temperature, or to one of these parameters. The results of experimental studies on the simultaneous control by the proposed method of deformation and temperature of a structurally similar sample from a carbon composite processed by a vacuum method from a prepreg are presented. It has been established that the use of a quadratic model for optical control of structurally similar samples of carbon composite makes it possible to increase the accuracy of deformation and temperature measurements in comparison with the linear control model. It is confirmed that the proposed experimental technique allows for simultaneous control of deformation and temperature of structurally similar samples from carbon composites, while it can be adjusted and adapted to the actual operating conditions of a particular structure.