An initial step in a blind source separation method to determine the baseline signal with acoustic emission

The ability to be able to diagnose problems in marine engines quickly and accurately is vital to the safe operation of any ship. Changes sound emanating from the operating system inside the engine room of a ship into vital information for early detection of the condition of the engine. This paper presents baseline signal measurement technique to detect early cracks that occur on the propeller shaft. Baseline signal measurement as a first stage application of Blind Source Separation method for separating a complex sound. The study was conducted in an anechoic chamber. Three test shafts dibuat dengan kedalaman crack yang bervariasi, masing - masing poros dengan kedalaman crack 0% (healthy shaft), another shaft dengan kedalaman crack 25% diberi nama cracked shaft 0.25D and the third was cracked shaft with 50 % dari diameter poros D (0.5D). The test shaft was rotated at shaft speeds from 500 to 1000 rpm by an electric motor. The microphone as Acoustic Emission sensor was placed at various distances as long as of test shaft from 5 to 40 cm. And the accelerometer attached on the casing the electric motor. The sound of data is measured for 5 seconds and then processed through signal processing. Acoustic signal spectrums on each measurement position are different from one another. Note that the spectrums amplitude are approximately equal to the microphone position 30 and 40 cm. Locations around the crack are in the measurement position. Another result is if the shaft speed improved then the amplitude value will increase. These findings indicate that the acoustic emission technique may be a suitable replacement to an accelerometer-based measurement. And be as specific finding is the initial step of baseline measurements successfully performed as data references to the application of Blind Source Separation method further.