Towards a simplified technique for crack recognition in gearing systems

This paper presents a simple and effective method to identify and quantify the existence of cracks in the teeth roots of spur gears. The problem was numerically analyzed through finite element-based simulation with SolidWorks in the first part of this work. The computed tooth in-plane bending stiffness and natural frequency decreased considerably with an increase in the crack length, while the deformation followed an opposite trend. The numerical results were experimentally validated through a convenient and straightforward test rig developed for this purpose. The experimental results obtained from the modal analysis tests confirmed the previously obtained numerical results. A graphical representation of these parameters on a polar plot shows concentric circles with no particular sign from one tooth to another. However, in the presence of cracks in the vicinity of teeth roots, these circular patterns became deformed in the neighborhood of the teeth with defect, which provides a quick and easy visual check to detect a crack and quantify its extent.