Research On Laser Spot Welding And Numerical Simulation Of Thermal Distortion About Fibre Coupler

Fiber Coupler is the key device in fiber communication, and it is the optical signal splitter/combiners road functional devices which is widely used in optical transmission systems, cable, LAN. In recent years, with the development of fiber-optic communications, the fiber coupler requirement is growing. Since with precision, cleaning and reliability inherent attributes, Laser welding is becoming the best choice for connecting fiber devices. But in fiber coupler laser welding process, welding site's rapid solidification and contraction of related materials may lead to relative displacement of pre-aligning device which may significantly reduce the efficiency of connecting.This thesis analyzes the spot morphology and the hardness and microstructure of the weld. The effect of welding parameter on the welding seam properties has been researched. It has showed that the depth of seam and the diameter of conjoint are increased with the increasing of energy and also has showed that the depth of seam and the diameter of conjoint and hollow of the seam are increased with the increasing of impulse width. Then this thesis analyzes the effect of different welding sequence of the fiber-coupled laser spot welding spot on the temperature and stress the distribution of simulation by ANSYS software. Temperature fields at different time, residual stress in different locations and deformation were analyzed. The effect of the welding sequence alignment on deformation is estimated.The curves of thermal cycle at the different distance sections were analyzed and compared the thermal cycle curve of different welding sequence, the simulation results are accordant with the theoretical situation. In the stress fields, after cooling to room temperature, due to the contraction weld residual stress almost reached the limit of yielding; After the welding because of uneven distribution of temperature the seam produced deformation, deformation was basically the same with the actual situation. Through making a comparative analyse of welding-induced-alignment at different welding sequence. The results have shown that the effect of laser welding sequence on welding-induced-alignment-distortion for Fiber Coupler is significant.