光纤耦合器激光点焊研究及其热变形的数值模拟-材料加工工程专业论文.docxVIP

I I 摘 要 光纤耦合器是光纤通信中的关键器件，它是实现光信号分路/合路的功能器件， 属于光无源器件，广泛应用在光传输系统、有线电视、局域网中。随着近几年光纤 通信的迅速发展，对光纤耦合器的需求量日益增加。因为激光焊接具有精确性、清 洁和可靠性等固有属性，激光焊接正成为连接光纤器件的最佳选择。但是在光纤耦 合器激光点焊焊接过程中，由于焊接部位的快速凝固和相关材料的收缩可能引起预 对准器件之间的相对位移，这样的焊接引发的准直变形可能显著地降低连接效率。 本论文首先分析了光纤耦合器激光点焊的焊点的形貌、焊缝的硬度以及显微组 织，分析了焊接工艺参数对焊缝质量的影响。得出结论：随着能量的增加，焊缝的 熔深以及焊接结合处的直径均增加；随着脉宽的增加，焊点的熔深、焊点结合处的 直径以及焊点的凹陷都增加。本论文还利用 ANSYS 平台对不同焊接次序下的光纤耦 合器激光点焊焊点的温度场和应力场的分布进行了模拟，分析了不同时刻的温度场 分布，应力场的分布以及最终的变形情况。并对光纤耦合器中激光焊接顺序对焊接 引发的准直变形的影响进行了评定。 对距焊缝中心不同位置点的热循环曲线进行了分析，并对不同焊接次序下热循 环曲线做了比较，曲线变化与理论分析基本一致。在应力场分析中，焊接完成冷却 到室温后，由于焊缝收缩而导致残余应力几乎达到材料的屈服极限；焊后由于焊缝 温度分布不均而产生变形，变形情况与实际情况基本一致。通过对不同焊接次序下 的准直变形做的对比分析，得出结论：焊接次序的选择对焊接后的准直变形影响很 大。 关键词：激光焊接 光纤耦合器 数值模拟 温度场 残余应力场 准直变形 II II Abstract 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 s