Research Of Mechanical Reliability And Life Of Fiber Optic

Compared with the cable,optical fiber communication has many advantages,such as low loss,large bandwidth,good security and so on,thus more and more applications.Since the first fiber optic cable laying in China,it has been nearly 25 years,close to or basically meet the communications industry standard YD/T 769 specified in the shortest fiber optic cable life 25 years [1].It is necessary to assess the service life of the cable and extension techniques.Fiber optic cable is the most important key material of fiber optic cable.To improve the service life of fiber optic cable,the most fundamental is to improve fiber reliability.In this thesis,the mechanical reliability and life evaluation of fiber optics are selected as the research topic.The main contents can be summarized as follows:(1)The main factors that affect the mechanical reliability of optical fiber are studied.The optical fiber crack growth theory,optical fiber fatigue fracture mechanism,fatigue parameters and test methods,optical fiber zero stress corrosion phenomena and mechanism,the coating on the mechanical properties of optical fiber.(2)According to the factors that influence the mechanical reliability of optical fiber,we select the frequency,length and breaking probability of the fracture point according to the screening test.Weibull parameter model is also used to establish the expected fiber life.It is found from the model that the Weibull parameter m,the fatigue index n,and the applied strain are parameters sensitive to fiber lifetime evaluation.(3)Testing and investigation of the main parameters affecting the reliability of optical fiber.The two methods of bending and axial tension measurement of optical fiber Nd are discussed,and the difference of them is analyzed.(4)To explore ways to improve optical fiber mechanical reliability.By analyzing the existing optical fiber manufacturing and construction process,we can improve the fatigue index n and the applied strain?_a way,so as to improve the optical fiber reliability.The innovation of the thesis lies in:(1)Using optical fiber fatigue fracture mechanism,Weibull model and screening test to establish fiber life expectancy model.(2)The dynamic fatigue parameters of optical fiber two kinds of test methods for the difference analysis.(3)Considering the n-value of optical fiber and the manufacturing process,we can improve the mechanical reliability of the fiber,which can be applied in the project.It has practical significance for the manufacture and construction of optical fiber.