Damage detection system for automated hot spot monitoring based on different technologies used in component testing for shot peening validation

Abstract

Structural Health Monitoring (SHM) is an important requirement to handle military aircraft safety. In contrast with civil aircraft, missions, configurations and environment are changing frequently and therefore also the load spectra, which lead to various life consumptions. Event and fatigue monitoring, remaining life assessment and damage detection monitoring are the basic functions for economic and safe in-service operations of a flying weapon system. Hot spot monitoring for damage detection is an important part of modern SHM systems which can be installed in new aircraft as well as in existing aging aircraft structures. The availability of information on damage dimension is essential for a risk evaluation. Information on the damage growth delivers the input for degradation prognostics. Together with data from the individual usage and loads monitoring, a remaining life assessment is possible. This assessment is part of an integrated health monitoring system. Basic functionalities and an approach for the architecture will be described. This paper describes the results of complex landing gear component tests conducted for the validation of shot peening life enhancements. Details on life benefit due to the residual stresses of the high-strength aluminium alloy design will be presented. One part of the testing was to evaluate the performance of hot spot monitoring technologies using imaging ultrasonic and acoustic emission sensors. Initial objectives of the tests were to obtain information on durability, reliability of the sensor system and system validation. Automatic signal processing and damage size quantification were further objectives of the tests. Referring to this test experience, new ideas for hot spot monitoring, combining different technologies in one system will be presented and the requirements for further development on a modern SHM-System and its implementation into an integrated health monitoring system will be discussed.