A novel predictive model for multiaxial fatigue in carburized bevel gears

Abstract

This publication focuses on the numerical stress prediction in case‐carburized bevel gears and on their fatigue assessment. Four gear sets are analyzed for the common fatigue failure modes of pitting, tooth root breakage, and subsurface fatigue. The proposed algorithm, enabling the prediction of the dominant failure type and region, relies on the previously published material model for carburized CrNiMo steels. It utilizes a 2D plane strain simplification as only the mean cross‐section is analyzed and evaluates the shear mean and amplitude stresses through the maximum rectangular hull method. A novel multiaxial fatigue criterion is presented and validated.

Benchmarking Newer Multiaxial Fatigue Strength Criteria on Data Sets of Various Sizes

“…The paper reports on a comparison of six recently introduced multiaxial fatigue strength estimation criteria-the KP criterion by Khalij et al [36], the WS criterion by Wang et al [43], the Böhme criterion [46], the MDC criterion by Margetin et al [48], the MMMH criterion by Mertens et al [51], and the Yankin criterion [53]. To refer to their quality, the complete FatLim data set [32] and the abbreviated AMSD25 data set [31] were used for validation.…”

“…This worsening can be attributed to the response to the two load cases with compressive mean stresses on the cast iron tested by Rausch [56], i.e., in the domain, for which Böhme originally developed his model. The benchmarking done in [46] did not detect this issue, because it focused solely on cases including the shear stress amplitude, whereas the Rausch's tests causing problems here are solely uniaxial. If these two tests are removed, the ∆FI statistics of the {Ax} group improves to values achieved by PIN or PCN.…”

“…The recently published criterion [46] was derived by its author to deal well with fatigue in gear teeth, where not only the fatigue response on the surface of the gear tooth was analyzed, but the same criterion should also be applicable in the gear tooth core. This requirement is induced by the fact that the case-hardened gears have substantially different properties on the surface and in the core and that the observed failures can be initiated deep below the surface in the area where the case ends.…”

“…Böhme had to deal with compressive mean stresses in his tasks, and he wanted to ensure that negative mean normal stress will not lead to decreasing equivalent stress down to negative values below the square root, while the mean shear stress effect should be involved in some way. The authors of [46] benchmarked several criteria on the test set that comprises 23 load cases derived from the FatLim database, which included both axial mean stress and the shear stress amplitude. The Böhme criterion was only slightly worse than the best performing PIN criterion [17], which, however, failed to provide adequate damage distribution for analysis of real gear teeth.…”

Stress calculation on bevel gears with FEM influence vectors

“…In the field of volume capacity, there are many simulations and experimental studies, e.g. Wirth [8], Bauer [10] and others [14][15][16][17][18][19][20][21][22]. Currently, there is no subsurface flank fracture ISO Standard for bevel gears available.…”