Local stresses and material damping in very high cycle fatigue

Kazymyrovych, Vitaliy; Bergström, Jens; Thuvander, Fredrik

doi:10.1016/j.ijfatigue.2010.03.007

Cited by 21 publications

(21 citation statements)

References 5 publications

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“…In this work, the mass proportional damping is ignored because it is effective for low-frequency vibrations. The value of β is taken based on the estimate made by inverse modelling in [26].…”

Section: An Overviewmentioning

confidence: 99%

A study on high-speed rolling contact between a wheel and a contaminated rail

Zhao

Wen

Zhu

et al. 2014

Vehicle System Dynamics

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A 3-D explicit finite element model is developed to investigate the transient wheel-rail rolling contact in the presence of rail contamination or short low adhesion zones (LAZs). A transient analysis is required because the wheel passes by a short LAZ very quickly, especially at high speeds. A surface-to-surface contact algorithm (by the penalty method) is employed to solve the frictional rolling contact between the wheel and the rail meshed by solid elements. The LAZ is simulated by a varying coefficient of friction along the rail. Different traction efforts and action of the traction control system triggered by the LAZ are simulated by applying a time-dependent driving torque to the wheel axle. Structural flexibilities of the vehicle-track system are considered properly. Analysis focuses on the contact forces, creepage, contact stresses and the derived frictional work and plastic deformation. It is found that the longitudinal contact force and the maximum surface shear stress in the contact patch become obviously lower in the LAZ and much higher as the wheel re-enters the dry rail section. Consequently, a higher wear rate and larger plastic flow are expected at the location where the dry contact starts to be rebuilt. In other words, contact surface damages such as wheel flats and rail burns may come into being because of the LAZ. Length of the LAZ, the traction level, etc. are varied. The results also show that local contact surface damages may still occur as the traction control system acts.

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Section: An Overviewmentioning

confidence: 99%

A study on high-speed rolling contact between a wheel and a contaminated rail

Zhao

Wen

Zhu

et al. 2014

Vehicle System Dynamics

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“…Therefore, the mass proportional damping is not suitable for this work and only the stiffness proportional damping is employed. The value of β is chosen based on the estimate made by Kazymyrovych et al (2010), in which β for an FE model was determined by matching the measured stress level during testing with the level calculated using the FE method.…”

Section: Materials Modelmentioning

confidence: 99%

Modeling of high-speed wheel-rail rolling contact on a corrugated rail and corrugation development

Zhao

Wen

Heng-yu

et al. 2014

JZUS-A

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Short pitch rail corrugations were observed on a recently opened Chinese high-speed line. On the basis of field measurements and observations of corrugations occurred on the high-speed line, a 3D transient rolling contact model is developed using the explicit finite element (FE) method to investigate high-speed vehicle-track interactions in the presence of rail corrugations. The rotational and translational movements of the wheel are introduced as initial conditions in the model. The frictional rolling contact between the wheel and the corrugated rail is solved by a penalty method based surface-to-surface contact algorithm with Coulomb's law of friction. The contact filter effect is considered automatically by the finite size of the contact patch. Through specifying a time-dependent driving torque applied to the wheel axle, the tangential vehicle-track interaction on the corrugated rail is analyzed in the time domain together with the normal one at different traction levels and at rolling speeds of up to 500 km/h. This analysis focuses on detailed contact solutions, such as distributions of the pressure, surface shear stress, Von Mises (V-M) stress, and frictional work. The corrugation dimensions, traction level, and rolling speed are varied to investigate their influences, building a solid basis for further studying the material damage mechanisms. A theory is proposed based on the simulations to explain the observed phenomenon that the corrugation gradually stabilizes. The traditional multi-body approach is found to overestimate the dynamic wheel-rail interaction on a corrugated rail.

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“…Typical defects produced by AM processes are pores, voids, metallic inclusions, lack of fusion, among others 6 . It has been reported by several authors that all the mentioned defects favor crack initiation in the VHCF regime [6][7][8][9][10][11][12] .…”

Section: Introductionmentioning

confidence: 96%

Experimental Study of VHCF Fractographic Features of Conventionally and Additively Manufactured Steels

2023

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Materials produced by additive manufacturing (AM) have been extremely related to literature. However, there is still unconsolidated knowledge about the fatigue life and respective mechanisms of initiation of cracks predominant in the VHCF regime for these materials. What has been observed in materials produced by conventional routes is that fatigue cracks tend to nucleate from intrinsic defects of the material located internally or in subsurface regions. The change in the evolution process of fatigue cracks leads to the formation of a characteristic morphology on the fracture surface, known as "fish-eye". Another widespread aspect observed on the fracture surfaces is the formation of a fine granular area (FGA) nearby the initiation sites. This work aims to investigate the mechanisms of crack nucleation in VHCF of two distinct materials: conventional steel, DIN 34CrNiMo6 and AISI 316L stainless steel produced by L-DED. The ultrasonic tests were carried out at a frequency of 20±0,5 kHz and R= -1. The S-N curves were obtained and fracture surfaces were analyzed, fish-eye and FGA formation was verified. FGA sizes were compared to values estimated by empirical equations. FGA and fish-eye sizes were related to stress amplitude and maximum stress intensity factor (SIF).

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Local stresses and material damping in very high cycle fatigue

Cited by 21 publications

References 5 publications

A study on high-speed rolling contact between a wheel and a contaminated rail

A study on high-speed rolling contact between a wheel and a contaminated rail

Modeling of high-speed wheel-rail rolling contact on a corrugated rail and corrugation development

Experimental Study of VHCF Fractographic Features of Conventionally and Additively Manufactured Steels

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