Advanced vibration diagnostics for engine test cells

Current engine test cell systems were designed to perform a simple vibration amplitude check. If the root mean square (RMS) vibration amplitude falls within specifications under programmed operating conditions with no need for adjustments, then the engine is considered to be ready for installation. Engine test cell vibration analysis techniques are being developed to improve engine reliability and availability while simultaneously reducing life cycle costs. The engine test cell vibration diagnostic system under development provides both real-time and post-test analysis of engine vibration data. The real-time vibration diagnostic system identifies sensor faults before they lead to an incorrect diagnosis and plots key vibration diagnostic features such as tracked orders during the test. Vibration sensor faults are a common cause of test cell ineffectiveness. The post-test vibration diagnostic software allows users to perform detailed examinations of vibration features including multiple engine order tracks and waterfall plots recorded by the real-time module. The post-test software also utilizes advanced feature extraction and analysis techniques (such as half engine orders, harmonics and sidebands) to diagnose incipient mechanical faults. In addition to describing the abovementioned techniques, this paper overviews vibration data transfer methods and design of the graphical user interface (GUI).