Fiber Bragg grating (FBG) is proposed to embed in the composites to monitor the variation of strains and temperature,however,the influence of embedment on the sensing performance is not clear in the current studies.In the process of embedment,the angle between OF (optical fiber) and carbon fiber in the adjacent prepreg will generate the internal stress,which affect the sensing performance.For the sake of the investigation on this influence,the composites embedded the varying angle of OF is prepared and tested under the variation of strains and temperature to observe the influence on the sensing.Obtained results indicated that the angle of OF will affect the sensing performance inculding strains and temperature.In the inspection under the temperature,the degree of fitting for the sensing curve decreases with the increasing angle.Also,the deviation of the data measured by OF and strain gauge increases with the angle,implying a bigger deviation.

The interfacial performance of the Fiber Bragg grating (FGB) embedded in the composite was studied and the influence of interface modification on the final profile of the spectra of the FBG sensor was examined. A type of polyamine (Pentaethylenehexamine, PEHA) was proposed to modify the coating of PI on FBG, and the interfacial performance was evaluated by a pull-out test. Sharp improvements of the interfacial shear strength (77%) were obtained by 40 min treatment of PEHA. Compared with untreated specimen, FGB spectra of treated specimen in the tensile tests show improved linearity within the test regime, which proves that the enhanced interface is beneficial for the sensing performance.

Optical fiber smart composites can be used to continuously monitor internal stress and damage of composite materials with good stability and reliability. However,these optical fibers are embedded manually at present,which results in low efficiency and poor consistency. Aiming at this problem,a high-efficiency automotive placement of optical-fiber smart composites manufacturing method is proposed and investigated in this paper. The parameters of conveying roller material,convey pressure,laying pressure and heating temperature are determined by the designed automotive placement. Optimized results indicate that small optical-fiber loss and a stable opticalfiber grating reflection spectrum can be obtained when the optical fiber is placed parallelly to carbon fiber with silicone rubber convey roller,the convey pressure of 15 N and the laying pressure of 300 N at 80 ℃,which can ensure the sensing performance of the optical fiber grating.