光纤布拉格光栅传感器超声波焊接封装及其热压传感特性

发布时间：2018-02-01 16:05

  本文关键词： 超声波焊接 光纤光栅传感器 封装 金属化 传感特性　出处：《南昌大学》2017年硕士论文　论文类型：学位论文

【摘要】：光纤布拉格光栅(Fiber Bragg Grating,FBG)传感器是光纤传感器的典型代表,具有重量轻,体积小,抗电磁干扰等优点,是智能结构中传感器最受欢迎的选择之一。超声波焊接具有固态成形、低温、低压、低能耗等优点,能够将诸如FBG之类易碎的传感器嵌入金属基体,获得可以感知自身温度和应变的智能结构或传感器件。本文对金属化FBG传感器超声波焊接嵌入铝合金进行了研究,具体包括:(1)宿主金属超声波焊接工艺优化。通过镀锡铝合金与镁合金的超声波焊接工艺优化和接头界面组织分析,对焊接接头形成机理进行研究,结果表明镀锡层的加入有效地阻止了镁铝的相互扩散,抑制了硬脆的Mg-Al系金属间化合物的生成,提高了镁铝超声波焊接接头强度,认为焊接界面塑性变形引起的机械嵌合和高空位浓度加速了接头界面的物理冶金过程是超声波焊接接头形成的主要原因;(2)FBG的金属化保护。采用化学镀镍和电镀镍对FBG进行金属化保护,化学镀镍层与光纤紧密结合,电镀镍层与化学镀镍层结合紧密,且成分相近,并对FBG金属化后的传感特性进行研究,研究结果表明,金属化后FBG的温度灵敏度为20.14 pm/℃,约为裸光栅的2倍,弯曲应变灵敏度为2.341 pm/μ?;(3)FBG传感器的超声波点动焊接封装工艺优化。超声波焊接时间45 ms,焊接压力5.4 MPa,金属镀层厚度为45μm,成功将金属化FBG嵌入厚度为0.3 mm的6061铝合金,纤嵌入强度为1.89N,并对嵌入过程进行了讨论;(4)超声波焊接封装的FBG传感器热压传感特性研究。FBG经超声波嵌入铝合金后仍然保持良好的波形,由于焊接封装时铝合金发生塑性变形,FBG封装时受机械压缩而中心波长发生蓝移;超声波焊接封装后FBG保持良好温度、应变传感特性,平均温度灵敏度为29.07 pm/℃,约为裸光栅的2.8倍,弯曲应变灵敏度为0.0973 pm/μ?。
[Abstract]:Fiber Bragg grating (FBG) sensor is a typical optical fiber sensor, which has the advantages of light weight, small volume, anti-electromagnetic interference and so on. Ultrasonic welding has the advantages of solid state forming, low temperature, low pressure and low energy consumption. It can embed fragile sensors such as FBG into metal matrix. An intelligent structure or sensing device which can sense temperature and strain is obtained. In this paper, ultrasonic welding embedded aluminum alloy with metallized FBG sensor is studied. The ultrasonic welding process of host metal is optimized. The forming mechanism of welded joint is studied by optimizing the ultrasonic welding process of tin plated aluminum alloy and magnesium alloy and analyzing the interface structure of the joint. The results show that the addition of tin coating can effectively prevent the diffusion of magnesium and aluminum, inhibit the formation of hard and brittle intermetallic compound of Mg-Al system, and improve the strength of ultrasonic welding joint of magnesium and aluminum. It is considered that the mechanical chimney caused by plastic deformation of the welding interface and the high altitude concentration accelerate the physical metallurgical process of the joint interface, which is the main reason for the formation of the ultrasonic welding joint. Electroless nickel plating and electroplating nickel are used to metallize FBG. The electroless nickel plating layer is closely combined with optical fiber and electroplated nickel layer is close to electroless nickel plating layer and the composition is similar. The results show that the temperature sensitivity of the metallized FBG is 20.14 pm / 鈩，

本文编号：1482260