Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors.

Liang Si,Horst Baier

doi:10.3390/s150716536

Abstract

For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM) technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. The proposed smart impact visualization inspection (IVI) technique mainly consists of five functional modules, which are the signal data preprocessing (SDP), the forward model generator (FMG), the impact positioning calculator (IPC), the inverse model operator (IMO) and structural state estimator (SSE). With regard to the verification of the practicality of the proposed IVI technique, various structure configurations are considered, which are a normal CFRP panel and another CFRP panel with “orange peel” surfaces and a cutout hole. Additionally, since robustness against several background disturbances is also an essential criterion for practical engineering demands, investigations and experimental tests are carried out under random vibration interfering noise (RVIN) conditions. The accuracy of the predictions for unknown impact events on composite structures using the IVI technique is validated under various structure configurations and under changing environmental conditions. The evaluated errors all fall well within a satisfactory limit range. Furthermore, it is concluded that the IVI technique is applicable for impact monitoring, diagnosis and assessment of aerospace composite structures in complex practical engineering environments.

Highlights

The use of composite materials in aerospace and automotive applications is increasing consistently due to their high specific strength, light weight, resistance to fatigue/corrosion and design flexibility.Typical application examples include the latest Airbus A380 aircraft that is 25% composite materials, and Airbus will be the first manufacturer to build an aircraft with an all-composite wing in their latestA350-XWB model and its entire structure will be composed of 45% composite materials
The issues concerning the assessments of estimated impact locations, the effects of various anisotropic panel structures on force reconstruction, the effects of different supporting structures on the force reconstructions and the effects of surrounding noise contamination on force reconstructions will be discussed in detail
Afterwards, in order to assess the estimated impact locations, the evaluated location error is defined in Equations (17)–(19), which is expressed as the distance from the calculated impact location to the actual impact location

Summary

Introduction

The use of composite materials in aerospace and automotive applications is increasing consistently due to their high specific strength, light weight, resistance to fatigue/corrosion and design flexibility.Typical application examples include the latest Airbus A380 aircraft that is 25% composite materials, and Airbus will be the first manufacturer to build an aircraft with an all-composite wing in their latestA350-XWB model and its entire structure will be composed of 45% composite materials. The use of composite materials in aerospace and automotive applications is increasing consistently due to their high specific strength, light weight, resistance to fatigue/corrosion and design flexibility. Typical application examples include the latest Airbus A380 aircraft that is 25% composite materials, and Airbus will be the first manufacturer to build an aircraft with an all-composite wing in their latest. A350-XWB model and its entire structure will be composed of 45% composite materials. The mechanical properties of composite materials may degrade severely if damaged. This damage may be caused by imperfections introduced during the manufacturing process or by external loads during the operational life, such as impacts by foreign objects. Damages due to impact such as matrix cracking, delamination and fiber breakage, significantly reduces the structural integrity of the composite structure. There exist some obvious shortcomings for the NDT technique, for instance, (1) the NDT instruments can’t be applied or attached permanently to the aerospace structure (or parts of the structure);

Methods

Results

Conclusion