Shaft Crack Monitoring by Using Acoustic Emission Technique

A power transmission shaft in rotational machines is a relatively important part of most applications. Frequently, fluctuated temperature, machine overload, and fatigue stress cause shaft cracking and finally broken that lead to machine breakdown and may damage some other mechanical components. Therefore, the shaft crack detection system using Acoustic Emission (AE) was developed in this study in order to prevent machine breakdown and subsequent damages. A test rig was designed and used for an endurance test. A notched shaft under radial bending fatigue was tested until its failure. An AE sensor mounted on a sleeve was monitored in real time to detect stress waves in terms of AE signal from crack initiation. The AE signal was amplified and transmitted to a personal computer via a data acquisition card. AE signal features were extracted to indicate the crack initiation and propagation. Using AE technique proposed in this study can successfully indicate shaft cracking at the early stage before its failure.