| The smart composite materials with optical fiber sensor embedded inside not only possess their mechanical properties,but also can monitor the deformation and damage of composite structures in real-time.It is widely used in aerospace,civil engineering,marine vessels and other fields.However,an 'eye-shape' interface is formed when the optical fiber sensor is embedded in composite materials.The existence of 'eye-shape' interface will influence both the original mechanical properties of composites and the sensor's own strain sensing performance.In this paper,the performance of fiber optic strain sensing and the mechanical properties of composites are studied.The main achievements are listed as follows:(1)Firstly,the application of optical fiber sensors in composite materials is reviewed.Then,we establish the geometry model and divide it into four parts,namely: optical fiber,coating,resin and matrix.Based on this model,the strain transfer rate of optical fiber is derived theoretically.(2)The factors which affect the transmission rate of strain are analyzed,such as embedded length of optical fiber,coating elastic modulus and size of sensor.With the help of ANSYS software,the finite element method is carried out to research the influence of these factors on the fiber strain transfer rate.After that,the numerical solutions obtained by ANSYS are compared with theoretical results.(3)The specimens required for strain transfer experiments are designed and produced.When finishing the experiment,the difference between experimental data and theoretical data is explained.During the production of specimens,the curing process of epoxy resin is also monitored.(4)The finite element models for different factors are established respectively to study the flexural and tensile properties of composites,these factors include fiber placement,composite layup direction,number of buried fibers,etc.The research results can provide guidance for the fabrication of embedded optical fiber smart composite material. |
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