A Flexible and Lightweight Impact Monitoring System with Ultra-low Power Consumption for Aircraft Smart Composite Skin

Abstract

Aircraft Smart Composite Skin (ASCS) which has the capability of Structural Health Monitoring (SHM) for large-scale aircraft composite structures to monitor impact needs to be developed because the poor impact resistance of composite structures may lead to barely visible impact damage and result in stiffness degradation and a significant loss of structural integrity. However, the impact is an instantaneous event so that it needs to be monitored on-line continuously during the whole service lifetime of the ASCS. Thus considering the strict restrictions of aerospace application, an impact monitoring system and sensor network is required to be low weight, low power consumption and high reliability. In this paper, an impact monitoring system with advantages of compactness, ultra-thin, light weight, ultra-low power consumption and high efficiency is developed to meet the strict requests of on-line application. Differently from conventional impact monitoring systems, the complex circuits are greatly simplified and the whole impact monitoring process is achieved in a digital way by turning the output of the piezoelectric sensors directly into digital sequences through a two-level digitalized mechanism which is realized by combing diode array with a Micro-Process Unit (MPU). A simple but efficient impact-region localization method is implemented in the MPU. In addition, the impact monitoring system is realized in a flexible way so that it can be embedded onto the composite structure to be a mechatronic system to realize impact monitoring on-line continuously. To illustrate the capability of the impact monitoring system, it is integrated with a flexible piezoelectric sensor array to construct a large-scale impact monitoring sensor network system. The network system is integrated on the surface of a large-scale stiffened carbon fiber reinforced plate to become an ASCS and the impact monitoring ability of the ASCS is validated.