RKB An Elastic-Plastic Analysis of Profile Evolution in Cylindrical Roller Bearings0 pages

Proceedings of the ASME 2012 11th Biennial Conference On Engineering Systems Design And Analysis
ESDA2012
July 2-4, 2012, Nantes, France
ESDA2012-82491
AN ELASTIC-PLASTIC ANALYSIS OF PROFILE EVOLUTION IN CYLINDRICAL
ROLLER BEARINGS
Spiridon S. Creţu*
RKB Europe SA
Balerna, 6828, Switzerland
Email: spiridon.cretu@rkbbearings.com
ABSTRACT
The roller profile appears to be the key element to attain a
longer rating life for both cylindrical and tapered roller
bearings. A genuine elastic analysis is able to optimize the
roller profile to obtain a stress distribution in the contact zones
that provides enhanced operational reliability and greater
insensitivity to misalignment. For traditional cylindricalcrowned roller profile design class I discontinuities exist at the
intersection points of roller profile with the crowning radius as
well as at the end chamfer. In an elastic analysis these
discontinuities generate very sharp increases in pressure
distribution diminishing the rating life of the bearing. In fact,
these local increases in pressure distribution are able to
overcome, locally, the yield limit and to induce both plastic
deformations and residual stresses. After a certain number of
cycles the material will shakedown elastically to a slightly
modified roller profile and a stable state of compressive
residual stresses. If were taken place, these changes have to be
considered in the life evaluation.
An analysis model has been developed to simulate the
nonlinear strain rate dependent deformation of rolling bearing
steel stressed in the elastic-plastic domain.
Marcelin I. Benchea
Technical University of Iasi
Iasi, 700050, Romania
Email: marcelin_ben@yahoo.com
The model is developed in the frame of the incremental theory
of plasticity by using the von Mises yield criterion and PrandtlReuss equations. By considering an isotropic and non-linear
kinematic hardening laws the model accounts for the cyclic
hardening phenomena. For each new load increment new
increments for the components of stress and strain tensors, but
also increments of residual stresses, are computed for each
point of the 3D mesh. Both the new contact geometry and
residual stresses distributions, are further considered as initial
values for the next loading cycle, the incremental technique
being reiterated. The cyclic evaluation process of both the
plastic strains and residual stresses is performed until the
material shakedowns. For the case of cylindrical roller
bearings with cylindrical-crowned roller profile, the role
played by the crowning geometry on pressure distribution is
pointed out for both the elastic analysis and elastic-plastic
analysis. Further, the modified rating lives are evaluated using
the methodology given in ISO 16281-2008.
KEYWORDS: elastic-plastic contact, non-linear hardening,
plastic deformation, cylindrical roller bearings, reference
rating life.
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*Address all correspondence to this author
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Copyright © 2012 by ASME