The present patent disclosure describes a test rig used for analyzing the fatigue of a shaft through strain and vibration measurements. This configuration allows for the replication of real-time operating conditions of the shaft in a rotating machine, aiding in the analysis of fatigue-induced vibration patterns. Refer FIG 1 & 2.

This Test Rig Consists of:

• A test bed;
• A pair of first bearings to support one end of the shaft;
• At least one load inducer that applies a static bending load to the shaft;
• At least one non-contact magnetic shaker that generates random load patterns, simulating real-world operating conditions;
• Multiple accelerometers, a laser vibrometer, a strain gauge, a proximity probe, and a tachometer for measuring vibrations, strains, and shaft responses

• This test rig and method are designed for assessing the fatigue life and integrity of a shaft under various loads and conditions, enabling early detection of potential issues such as fatigue cracks.

Method for Conducting Fatigue Analysis:

1. Positioning the Shaft: Place the shaft between the pair of first bearings.
2. Inducing Rotary Motion: Use the motor to induce rotary motion in the shaft.
3. Applying Static Load: A static bending load is applied to the shaft using the load inducer.
4. Inducing Random Load Profile: Use at least one non-contact magnetic shaker to induce random load profiles onto the shaft.
5. Analyzing Vibration Signatures: The vibration and strain responses recorded by the data acquisition system are analyzed for diagnosis and prognosis of fatigue-induced issues in the shaft, such as fatigue cracks.
6. Estimating Fatigue Life: The method may involve estimating the fatigue life of the shaft using either a time-domain approach or a frequency-domain approach.
7. Diagnosing Fatigue Cracks: The method may also involve diagnosing fatigue cracks in the shaft before they become critical in size using various methods, including time-domain, frequency-domain, and time-frequency domain approaches.