A Coupled Multibody Finite Element Model for Investigating Effects of Surface Defects on Rolling Contact Fatigue

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Zamzam Golmohammadi ◽  
Farshid Sadeghi

A coupled multibody elastic–plastic finite element (FE) model was developed to investigate the effects of surface defects, such as dents on rolling contact fatigue (RCF). The coupled Voronoi FE model was used to determine the contact pressure acting over the surface defect, internal stresses, damage, etc. In order to determine the shape of a dent and material pile up during the over rolling process, a rigid indenter was pressed against an elastic plastic semi-infinite domain. Continuum damage mechanics (CDM) was used to account for material degradation during RCF. Using CDM, spall initiation and propagation in a line contact was modeled and investigated. A parametric study using the model was performed to examine the effects of dent sharpness, pile up ratio, and applied load on the spall formation and fatigue life. The spall patterns were found to be consistent with experimental observations from the open literature. Moreover, the results demonstrated that the dent shape and sharpness had a significant effect on pressure and thus fatigue life. Higher dent sharpness ratios significantly reduced the fatigue life.

Author(s):  
Ivan Karin ◽  
Nils Lommatzsch ◽  
Klaus Lipp ◽  
Volker Landersheim ◽  
Holger Hanselka ◽  
...  

Within the collaborative research centre 666 “Integral Sheet Metal Design with Higher Order Bifurcations” the innovative manufacturing technologies linear flow-splitting and linear bend-splitting are researched that allow the continuous production of multi-chambered steel profiles in integral style. The massive forming processes create an ultra-fine grained microstructure in the forming area that is characterized by an increased hardness and lower surface roughness compared to as received material. These properties predestine the technology to be used in the production of linear guides. Additionally, the multi-chambered structure of the linear flow-split and -bend components can be used for function integration. To design and evaluate linear guides that use the whole technological potential, the research is focused on a macroscopic and a microscopic point of view. The macroscopic approach is targeting the development of linear flow-split linear guides with integrated functions to provide additional performance values to the established machine parts. Continuously produced guidance systems with innovative functionality can be introduced to a new market with the technology push approach. Preliminary designs of linear flow-split guidance systems and integrated functions are promising. Therefore, an approach to develop new functions for linear flow-split linear guides basing on calculation models and property networks is shown [1]. With this approach, optimized solutions can be created and possible design modifications can be derived. In this contribution, the development and integration of a clamping function for decelerating the slide is presented. Calculation models for analyzing the functionality are presented and validated by finite element models and experiments. The microscopic examination of the profiles aims to investigate the material behavior, particularly of the formed areas. Beside the conventional mechanical and fatigue properties of linear flow-split material ZStE500 [2], the present work focuses on the rolling contact fatigue. This is necessary to evaluate linear flow-split components regarding their eligibility with regard to the rolling contact fatigue behaviour. The Hertz theory for rolling contact fatigue is only valid for homogeneous materials [3]. The flow-split material ZStE500 shows a non-homogeneous behaviour and has to be analyzed with the Finite Element Method in order to determine stresses and strains. In comparison to simulation results with unformed and therefore homogeneous material, the effect of linear flow-split surfaces on the rolling contact behavior is demonstrated. Based on these results, it is possible to start experimental investigations on rolling contact fatigue of linear flow-split components to validate the FE model and determine the performance of linear flow-split flanges for rolling contact fatigue.


Author(s):  
Spiridon Cretu

An analysis model has been developed to model the nonlinear strain rate dependent deformation of rolling bearing steel stressed in the elastic-plastic domain. The model is developed in the frame of the incremental theory of plasticity by using the von Mises yield criterion and Prandtl-Reuss equations. By considering the isotropic and non-linear kinematic hardening laws of Lemaitre-Caboche, the model accounts for the cyclic hardening phenomena. To attain the final load of each loading cycle, the two bodies are brought into contact incrementally. 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, plastic strains and residual stresses is performed until the material shakedowns. The experimental part of the paper regards to the rolling contact fatigue tests carried out on two groups of line contact test specimens and on two groups of deep groove ball bearings. In both cases, the experimental data reveal more than two times greater fatigue life for the group with induced residual stresses versus the life of the reference group. The von Mises equivalent stress is considered in Ioannides-Harris rolling contact fatigue model to obtain theoretical lives. The theoretical analysis revealed greater fatigue lives for the test specimens and for the ball bearings groups with induced residual stresses than the fatigue lives of the corresponding reference groups.


2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Dallin Morris ◽  
Farshid Sadeghi ◽  
Yong-Ching Chen ◽  
Chinpei Wang ◽  
Ben Wang

Rolling contact fatigue (RCF) induces a complex subsurface stress state, which produces significant microstructural alterations within bearing steels. A novel modeling approach is presented in this paper, which investigates the effects of microstructural deterioration, phase transformations, and residual stress (RS) formation occurring within bearing steels subject to RCF. The continuum damage mechanics approach was implemented to capture microstructural decay. State and dissipation functions corresponding to the damage mechanics process were used via an energy criterion to predict the phase transformations of retained austenite (RA). Experimental measurements for RA decomposition and corresponding RS were combined to produce a function providing RS formation as a function of RA decomposition and stress history within the material. Microstructural decay, phase transformations, and internal stresses were implemented within a two-dimensional (2D) finite element analysis (FEA) line contact model to investigate variation in microstructural alterations due to RSs present within the material. In order to verify the model developed for this investigation, initial simulations were performed implementing conditions of previously published experimental work and directly comparing to observed RA decomposition and RS formation in 52100 steel deep groove ball bearings. The finite element model developed was then used to implement various RS profiles commonly observed due to manufacturing processes such as laser-shot peening and carburizing. It was found that some RS profiles are beneficial in altering RA decomposition patterns and increasing life while others proved less advantageous.


2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Behrooz Jalalahmadi ◽  
Farshid Sadeghi

Microlevel material failure has been recognized as one of the main modes of failure for rolling contact fatigue (RCF) of bearing. Therefore, microlevel features of materials will be of significant importance to RCF investigation. At the microlevel, materials consist of randomly shaped and sized grains, which cannot be properly analyzed using the classical and commercially available finite element method. Hence, in this investigation, a Voronoi finite element method (VFEM) was developed to simulate the microstructure of bearing materials. The VFEM was then used to investigate the effects of microstructure randomness on rolling contact fatigue. Here two different types of randomness are considered: (i) randomness in the microstructure due to random shapes and sizes of the material grains, and (ii) the randomness in the material properties considering a normally (Gaussian) distributed elastic modulus. In this investigation, in order to determine the fatigue life, the model proposed by Raje et al. (“A Numerical Model for Life Scatter in Rolling Element Bearings,” ASME J. Tribol., 130, pp. 011011-1–011011-10), which is based on the Lundberg–Palmgren theory (“Dynamic Capacity of Rolling Bearings,” Acta Polytech. Scand., Mech. Eng. Ser., 1(3), pp. 7–53), is used. This model relates fatigue life to a critical stress quantity and its corresponding depth, but instead of explicitly assuming a Weibull distribution of fatigue lives, the life distribution is obtained as an outcome of numerical simulations. We consider the maximum range of orthogonal shear stress and the maximum shear stress as the critical stress quantities. Forty domains are considered to study the effects of microstructure on the fatigue life of bearings. It is observed that the Weibull slope calculated for the obtained fatigue lives is in good agreement with previous experimental studies and analytical results. Introduction of inhomogeneous elastic modulus and initial flaws within the material domain increases the average critical stresses and decreases the Weibull slope.


2012 ◽  
Vol 503-504 ◽  
pp. 1029-1032
Author(s):  
Jing Ling Zhou ◽  
Wei Ming Zuo ◽  
Yu Jing Li ◽  
Yu Song Ren ◽  
Wei Nan Zhu

The Modal Analysis of the Ceramic Ball Rolling Contact Fatigue Life Test Rig Drive Shaft Abstract: With the increasing of the rolling contact fatigue life tester’s speed, the vibration problem is getting more and more serious. In order to optimize the dynamic performance test rig, the modal analysis of the drive shaft was carried. First the vibration mechanics model was got by simplifying the shaft and get the first order of horizontal natural frequency which is 787.4266Hz with the theoretic algorithm. Then the drive shaft’s modal analysis was made by using the finite element software and that is 779Hz. The relative error between the former and the latter is 1.1%. It has demonstrated the accuracy of the finite element result, and its modal analysis could be the basis of the dynamic optimization.


2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Yuan Gao ◽  
Ping Wang ◽  
Yibin Liu ◽  
Jingmang Xu ◽  
Zhiguo Dong ◽  
...  

Flange bearing frogs are designed to provide continuous rolling surfaces for trains traveling on the through line, but the interaction between wheel and rail in a diverging line is more complex than that for a common crossing, especially including flange bearing mode and multipoint contact during the transition. The wheel load will be transited from tread to flange and back to tread, which will intensify the wheel-rail interaction. In this paper, a numerical procedure is presented for the analysis of wheel-rail rolling contact behavior and damage prediction for the flange bearing frog. The three-dimensional explicit finite element (FE) model of a wheel passing the flange bearing frog is established to obtain the dynamic wheel-rail interaction in both the facing and the trailing move. The evolution of contact forces, the distribution of adhesion-slip regions, and shear surface stress and microslip at the contact patch are revealed. Then, the competition relationship between RCF (rolling contact fatigue) and wear of a flange bearing frog is analyzed. The results of numerical simulations can contribute to an understanding of the mechanism of the transient rolling contact behavior and provide guidance in design optimization for flange bearing frogs.


2012 ◽  
Vol 503-504 ◽  
pp. 667-670
Author(s):  
Jing Ling Zhou ◽  
Wei Nan Zhu ◽  
Guo Qing Wu ◽  
Yu Song Ren

The RCF (Rolling Contact Fatigue) life of bearing balls is a main method, to evaluate the performance of bearing materials and their production technology. In general, The RCF life of ceramic balls is a reliable technique to asses whether or not they are suitable to be used in rolling bearings. The RCF life of ceramic balls is depend on contact stresses chiefly. It applies the finite element analysis to calculate the surface stresses and subsurface stresses, including 1st principal tensile stresses and shear stresses. The theory results are compared with the finite element solutions. Very good agreement is observed. The finite element results in this paper have an important applied value. The results provided theoretical basis for rolling contact fatigue life prediction of the ceramic balls.


2016 ◽  
Vol 851 ◽  
pp. 346-351
Author(s):  
Li Hua Fu ◽  
Jian Yang ◽  
Yue Zhang ◽  
Hua Song ◽  
Wei Li

Wheel/rail rolling contact fatigue is one of the most complicated and urgent problems of the key techniques of railway system, and seriously influences the operational safety. A finite element (FE) model of wheel/rail rolling contact of curve negotiation is established based on the single-layer track dynamic model, which is considering the effect of rail straightening residual stress, the actual wheel tread and the elastic support of rail track bed. The nominal stress approach is applied to study the rail rolling contact fatigue life with two residual stress-state conditions. Results show that the distribution of rolling contact fatigue life on the surface of rail head presents obvious peaks and troughs with a specific wavelength in the longitudinal direction, which are approximately corresponding to the peaks and troughs of the contact force. Meanwhile, the rail rolling contact fatigue life firstly increases and then decreases while the running speed varying from 150 to 250 km/h, and decreases while the axle load varying from 13 to 17 tonnes which do not fully show a linear law.


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