Analysis and Optimization of Distributed Welding Technology for Submillimeter Metallized Package Structure of Fiber Optic Sensor Transmission Line

The continuous increase in operating temperature of aero-engines poses a series of thorny problems for performance testing, including the problem of fixing the sensor transmission line in the narrow space of the engine under high temperature conditions. The metal-encapsulated optical fiber transmission line is beneficial for improving its mechanical strength and facilitating welding and fixing. However, the high temperature molten pool in the welding process can easily damage the optical fiber, resulting in low reliability. In this study, a finite element model was constructed to investigate the multi-physical field coupling in the resistance spot welding process for the fiber submillimeter metallization package structure. The study systematically examined the generation and evolution of the micro-welding pool in stainless steel pipes, as well as the evolution of the temperature field. The method for assessing welding quality under the influence of multiple parameters was proposed. It revealed the influence of different process parameters on the temperature field and achieved parameter optimization. The problems of easy fiber breakage and large optical loss are resolved in the traditional welding process, ensuring reliable transmission of sensor signals.