A Multi-Functional Sensor Network System for Health Monitoring of Inflatable Softgoods Structures

A multi-functional sensor network system (MFSNS) was developed for long-duration structural health monitoring (SHM) of inflatable softgoods structures in space habitats. This MFSNS utilizes a set of flexible piezoelectric sensors, which are embedded into the softgoods structure, to simultaneously perform passive acoustic emission (AE) detection, active ultrasonic guided wave (UGW) testing and local strain sensing (SS). Damage precursors/initiation and growth in the softgoods structure can be monitored through AE. The damage/defects in the structure can be detected and characterized through UGW. The creep in softgoods materials can be detected through SS at the sensor location. By continuously detecting AE, UGW, and SS signals, the health condition of inflatable softgoods structures in space habitats can be monitored and the remaining useful life (RUL) can be predicted. In this paper, a MFSNS prototype was developed and demonstrated. Flexible microfiber composite (MFC) sensors were used as the sensing elements. A multichannel, multi-mode data acquisition unit along with a software package were developed. Damage detection and material characterization algorithms were developed for AE, UGW, and SS detection. Experimental results confirm that the MFSNS is capable of performing simultaneous AE, UGW, and SS measurements on softgoods materials, making it promising for long-term SHM and RUL prediction of softgoods structures in space habitats.