Sub-zero temperature influence on the durability of additive manufactured composite with embedded fiber Bragg grating sensors

Additive manufacturing (AM) techniques can be applied for the production of carbon fiber reinforced polymer (CFRP) elements. There is a possibility of embedding fiber Bragg grating (FBG) sensors into elements during the manufacturing process. The embedded FBG sensors can be applied for measurements of the element internal temperature and strain. The goal of the paper is to analyze the influence of sub-zero temperatures on the AM CFRP material durability. The measurements were performed on the samples with FBG sensors embedded into the composite during the manufacturing process. It allows to online monitoring of internal strain in the material during its exposition on sub-zero temperatures and mechanical loading. Additionally, the influence of embedded FBG sensors and temperature on the mechanical strength was determined using the tensile tensile test. It was observed that the influence of embedded FBG sensors on the samples structure is neglected. The samples microstructures were also analysed using a scanning electron microscope (SEM). For the purpose of determination of the embedded sensors influence, the achieved results were compared with the results for similar samples without fiber optics. It was observed that exposition of CFRP material on sub-zero temperatures influenced on the microstructure of composite and the mechanical strength of the analysed samples.