Browsing by Author "Ameyaw, Daniel Adofo"

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    Crack Detection in Shaft Using Vibration Measurements and Analysis
    (2015-02-13) Ameyaw, Daniel Adofo
    Cracks in shafts have been identified as a significant factor limiting the safe and reliable operation of machines. Cracked shafts still pose a significant and real threat to machines in spite of the great advances made in the areas of metallurgy, design and manufacturing. The ability to detect cracks at an early stage of progression is imperative to avert the aforementioned consequences which include failure of equipment resulting in costly process upsets and repairs among others. In this work, torsional and transverse vibration experiments are carried out to investigate transverse crack signatures for a shaft. The effect of the depth and position of an open transverse crack on the shaft’s torsional rigidity, fundamental peak acceleration, and natural frequency was investigated. A Matlab program was also developed to aid in the computation of the natural frequency for any given crack depth and position. The program also makes it possible to calculate the deflection of the shaft mass and the masses (rotor) it carries for any given crack depth. Numerical studies were also carried out by modelling the crack using Solidworks (ver.2014) to compute the frequency. From the work, it was evident that the presence of a crack affects its modal properties and cracks at the centre posed a higher risk as compared to those at the ends. Comparing the results from the three approaches, it was observed that the analytical results were closer to that of the experimental though the numerical also gave very good results.