Method for calculating damping based on fluid inertia effect and fatigue test method and apparatus using the same

A resonance fatigue test method for a test article, the method comprising steps of:

• calculating a damping ratio by considering an air inertia damping caused by a delayed response of air flow development among a fluid inertia effect on an oscillation of the test article;
• constructing a damping model for predicting at least one of an amplitude of the test article and a test bending moment, based on the calculated damping ratio;
• and
• performing a resonance fatigue test based on the constructed damping model.

A resonance fatigue test apparatus for a test article, the apparatus comprising:

• a test stand configured to fix one end of the test article;
• an exciter mounted on the test article and configured to apply a repeated force to the test article so as to induce oscillation;
• a controller connected to the exciter and configured to apply a driving force to the exciter;
• and
• a processor configured to calculate a damping ratio by considering an air inertia damping caused by a delayed response of air flow development among a fluid inertia effect on an oscillation of the test article, to construct a damping model for predicting at least one of an amplitude of the test article and a test bending moment, based on the calculated damping ratio, and to offer a control signal for performing a resonance fatigue test based on the constructed damping model to the controller.