根据热粘弹流变理论和时温等效原理,以广义Maxwell模型模拟高温下熔融光纤玻璃的粘弹特性,建立了光纤耦合器熔融拉锥过程热粘弹数值分析模型,采用热电偶和电位差计测定了气体火焰的温度;并以此温度场作为边界条件,结合有限元软件对光纤耦合器熔融拉锥过程进行热瞬态数值分析,得到了光纤耦合器在熔融拉伸过程中的应力应变场。实验结果表明:当最高温度为1171℃,拉伸速度为0.15μm/s时,最大拉应力为20.0MPa;光纤内部的最大等效应力与拉锥速度呈正比,且在拉伸的过程进行大约0.4s后光纤内部应力达到稳定。
Based on thermal rheological theory and time-temperature equivalent principle, the generalized Maxwell model was used to simulate viscoelastic characteristic of fused optical fiber glass. The thermal viscoelastic model of fiber coupler in the process of fused biconical taper was set up. Fused temperature field was measured with thermocouple and potentiometer. Using the temperature as the boundary condition field, the transient analysis of fiber coupler in the process of fused biconical taper was accomplished and stress-strain field was obtained. The results show that when the maximum temperature is 1 171 ℃ and drawing speed is 0.15 μm/s, the maximum stress is 20.0 MPa; the maximum stress is in direct proportion to drawing speed, and it is about 0.4 s when the stress field becomes stable.