An Active Diagnostic System for Structural Health Monitoring of Rocket Engines

Abstract

An active diagnostic system using built-in piezoelectric actuator/sensor networks was developed for monitoring crack growth in a rocket engine pipe. The diagnostic system combines a sensor network, portable diagnostic hardware and data analysis software which allows for real-time in situ monitoring and long term tracking of the structural integrity of pressure vessels. Experimental data shows that the system can detect a surface crack as small as 4 mm and a through-crack as small as 2 mm in the high pressure engine pipe made of Inconel 718. It was found that the actuator-sensor paths that are most sensitive to crack growth are the ones in which the crack is growing away from, rather than towards the path. This discovery will provide important guidelines for the design of a sensor network for crack detection. It was also observed that the bending mode (equivalent to the A 0 mode in plates) is more sensitive than the longitudinal mode (equivalent to the S 0 mode in plates) to crack growth.

Identification of corrosion damage in submerged structures using fundamental anti-symmetric Lamb waves

“…Generally speaking, both the S 0 and A 0 modes can be used for identifying a variety of structural damage, although the S 0 mode exhibits higher sensitivity to damage in the structural thickness and delamination in particular [22][23][24], whereas the A 0 mode outperforms the S 0 mode with higher sensitivity to surface damage such as cracks, corrosion [25] or surface crack growth [26]. In recognition of the above observations and in particular the fact that the A 0 mode features a smaller wavelength in the relatively low frequency range compared with its symmetric counterparts and therefore enables scrutiny of damage of smaller dimension, the A 0 mode was employed for corrosion identification in this study.…”

SHM Supporting Damage Tolerance Design Philosophy As a Challenge for Designers of Future Airframes

“…A comprehensive theoretical study of the dynamic coupling between a surface piezoelectric sensor and an elastic half-plane are described in [7]. An active diagnostic system using built-in piezoelectric actuator/sensor networks was characterised in [8,14]. The recent development of a surface fatigue crack detection technique based on the use of surface-mount piezoelectric paint sensor are presented in [6].…”

Sensors/actuators network development for aeronautics structure health monitoring

“…Many non destructive commercial tools already exist to evaluate structures integrity. These ones are generally based on eddy current or ultrasonic emission to detect a flaw [3] [5] and are specialized on a single kind of material. These tools are also very local and therefore unsuitable for airplane inspection which is by definition time-consuming and needs many human resources.…”