Influence of multi-transverse crack on cantilever shaft

Analysis of transversely loaded cantilever shaft having multiple cracks is investigated in this paper. The behavior of cracks locations and sizes on vibration parameters is presented taking the advantage of reduction in stiffness of shaft from fracture mechanics. The shaft is subjected to static axial and bending load for given angle of twist along its longitudinal direction. Using the principle strain energy release rate and stress intensity factor (for plain stress and strain condition), the natural frequencies with their mode shapes at different crack locations with its depths are evaluated. The result obtained from theoretical method has been verified with the advantage of adaptive neuro-fuzzy inference system (ANFIS) using the modal parameter of cracked shaft. The vibration parameters such as first three non-dimensional natural frequencies with their mode shapes at different locations and depths are supplied to ANFIS to optimize the results. The crack location and size predicted from ANFIS model are verified with the theoretical data with acceptable error. The surface plot, residual error, and probability plot obtained from ANFIS are showing the effectiveness of theoretical method. Research work has been extended to set up an experimental model to strengthen both theoretical and ANFIS work.The paper basically focused on error percentage obtained from the theoretical result with ANFIS and experimental work. It is found that the error percentage in ANFIS and experimental analysis are ±2% and ±7.33% respectively with respect to theoretical analysis. The present method is simple and can be easily extended to complex structure with different orientation of multiple cracks for any structural analysis.