Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Influence of curvature on residual stress measurement by X-ray diffraction at the gear tooth root
Submission Author:
João Pedro Vieira , SP
Co-Authors:
João Pedro Vieira, Matheus Santos, Tiago Colombo, Ronnie Rego
Presenter: João Pedro Vieira
doi://10.26678/ABCM.COBEM2023.COB2023-0618
Abstract
The root area of the gear tooth geometry is an important site for the accurate assessment of gear condition, especially when considering tooth bending fatigue failure, as the maximum tensile stresses during operation are developed at the root radius. Due to its small diameter, a strong influence of curvature is expected on the stress values obtained, altering their accuracy and precision. In this regard, it is of interest to check whether residual stress measurements are valid at the root region and investigate to what extent they are affected by its curvature, which is the objective of this study. The procedure was carried out using the cosα X-ray diffraction technique on a controlled geometry stress relieved ASTM A36 block on which grooves with varying diameters were indented, as well as evaluation on case hardened steel alloy gear teeth. Residual stress measurements for the machined specimen indicated adequate accuracy for curved surfaces with diameters from 6 to 10 times larger than that of the equipment's collimator, especially in the axial direction. Measurements on a curved groove with diameter only 3 times larger than the collimator's showed significant curvature influence on the circumferential direction, indicated by the high disparity of the stress values obtained when compared to those of the other channels. The teeth roots of the ITA geometry gear were not affected by curvature influence despite their small dimensions, generating precise results for both directions. This behavior is likely due to X-rays being cast onto regions of the tooth root other than that with the smallest radius. Considering the importance of this specific area for evaluation of tooth bending fatigue, modifications are needed and proposed to the standard measurement technique utilizing the cosα X-ray diffraction method at the root region.
Keywords
residual stress, X-ray Diffraction, gear tooth root
