Shear Modulus Prediction from Modal Parameters of Shaft Under Cyclic Loading

Lim, Choon Hoong (2024) Shear Modulus Prediction from Modal Parameters of Shaft Under Cyclic Loading. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Fatigue failure is one of the most common failure occurred in rotating machinery components due to damage accumulation when subjecting to the fluctuating stresses and strains over a long period. The aim of this project is to conduct the shear modulus prediction by using the modal parameters obtained from the modal analysis technique, which is a non-destructive tool to study the correlation analysis and determine the inherent dynamic characteristics. Shear modulus can estimate the fatigue life of a material on when the materials will fail under cyclic loadings. In this project, the current existing approaches for fatigue life prediction are studied and the modal analysis is conducted on a shaft under cyclic loading to determine the structural behaviour, and the modal parameters measured are used for shear modulus prediction. Through modal analysis, the natural frequencies obtained in first mode shape are 832.84 Hz, 834.23 Hz, 837.18 Hz, 840.59 Hz and 860.18 Hz for aluminium shaft specimen and 909.16 Hz, 911.64 Hz, 913.01 Hz, 916.12 Hz and 918.28 Hz for mild steel shaft specimen. There is also twisting force applied to both materials until maximum of 16 N to obtain the torque values and twisting angles throughout the experiment. The correlation analysis is done based on the output results of modal analysis and torsional testing, where the shear modulus of aluminium can be obtained from linear graph of