A. Pedraza, A. López, D. Velilla
Although the occurrence of residual stresses is inherent to the manufacturing process of composite structures, and although their influence on the mechanical properties of the material is well known, the difficulty to measure the internal stresses in the laminate together with the multiple variables associated with the manufacturing process generally prevent the performance of a systematic study that relates the properties of the material with the stresses that originate in this process, mainly in the curing process. Fiber optic sensors based on Bragg networks have been used to measure stresses in the curing process for a long time. However, their use has not been widespread due to the cost of the sensors, their difficult handling, and the punctual information they provide. Thus, in this study, the results of the monitoring of curing by means of distributed measurement techniques based on Rayleigh scattering are presented. For this purpose, standardized specimens will be fabricated using IM7/8852 prepreg composite material and will be instrumented with fibers embedded in several. The stresses generated during the whole manufacturing process will be monitored, using molds with different thermal expansion coefficients. Additionally, measurements will be performed on symmetrical laminates manufactured by joining non-symmetrical laminates. Both the curing process and the mechanical tests will be continuously monitored using an optical interferometer OFDR (Optical Frequency-Domain Reflectometer) based on Rayleigh OBR (Optical Backscatter Reflectometry) scattering. The measurements obtained with this instrument will be processed with a technique capable of decoupling temperature and deformation.
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Accepted on 22/09/25Submitted on 06/06/25
Licence: Other
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