表面粘贴式光纤光栅传感器的动应变传递规律

Dynamic Strain Transfer Laws of Surface Bonded FBGSs

通过理论分析,以基体承受正弦动态载荷为例,建立了表面粘贴式光纤光栅动应变传递模型,确定了影响参数;运用有限元仿真法分析了影响动应变传递的各个参数;通过实验分析验证了理论与仿真分析结果。理论与实验分析表明:振动频率、粘贴长度、粘贴厚度和粘胶中间层厚度是影响表面粘贴式光纤光栅动应变传递的主要因素,粘贴宽度对动应变传递率影响较小;激振频率远小于结构固有频率时,动应变传递率基本维持不变,实验动应变传递率为92%;激振频率达到固有频率之前,动应变传递率随激振频率增大缓慢增大;粘贴长度大于光纤光栅栅区长度的2倍时,传递率明显优于粘贴长度较短者,实验动应变传递率为92%。

Firstly, as structure under sinusoidal load for example, a surface bonded FBG dynamic strain transfer model was established through theoretical analysis, and the influencing parameters were determined. Then, the influences of dynamic strain transfer parameters were analysed by using the finite element simulation method. Finally, the results of theory and simulation were verified by experimental analyses. The results of theory and experiments show that the vibration frequency, the length of glue, the thickness of glue and middle layer thickness of glue have major impacts on FBGS dynamic strain transfer rate. The width of glue has minor effects on the transfer rate. When the vibration frequency is far less than the structure natural frequency, the dynamic strain transfer rate remains the same through different frequencies and the experimental value is as 92 %. Before the vibration frequency achieves the natural frequency, the transfer rate increases very slowly with the increases of vibration frequencies. When the length of glue is more than 2 times of FBG length, the transfer rate will be obviously better than the rate of shorter, the experimental value is as 92%.