Shaker Fatigue Testing of a Turbine Engine Compressor Blade

摘要

Hamler Test and Analysis (HTA) provides testing, design, and finite-element analysis (FEA) consulting services, specializing in vibration measurement and experimental vibration analysis tools such as tap testing, modal analysis, operating deflection shapes analysis, and rotating machinery analysis. HTA was contracted to perform physical fatigue testing of a compressor blade from a stationary' gas turbine engine used for power generation. Electrodynamic shaker testing was required to verify the client's analytical vibratory high-cycle fatigue life prediction methodology. The first, phase of the shaker testing involved vibrating several blades to failure at the first bending mode, and the second phase involved testing several blades to failure at the first torsion mode. The primary challenge involved attaining an acceptable blade tip response displacement at the first bending mode frequency of 2,900 Hz. The target response was dictated by blade stress levels required by the customer during testing. Because displacement is directly proportional to acceleration, but inversely proportional to the square of frequency, the target displacement would be difficult to achieve at 2,900 Hz, even with the gain in response at resonance.