Further Research Into Wheel Rim Axial Residual Stress and Vertical Split Rim Failures

2012 ◽  
Author(s):  
Cameron Lonsdale ◽  
John Oliver
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Stress Profile ◽  
Residual Tensile Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wheel Rim ◽  
Axial Tensile ◽  
Axial Residual Stress ◽  
Class C

Recent work using x-ray diffraction techniques has shown that the axial residual stress pattern within the railroad wheel rim is significantly different for as-manufactured AAR Class C wheels vs. AAR Class C wheels that have failed due to a vertical split rim (VSR), and non-failed AAR Class C wheels that have been operating in service. VSRs almost always begin at areas of tread damage, resulting from shelling or spalling, and cracking propagates into the rim section under load. At the locations tested, the as-manufactured wheels have a relatively “flat” axial residual stress profile, compressive but near neutral, caused by the rim quenching operation, while wheels that have been in service have a layer of high axial compressive stress at the tread surface, and a balancing zone of axial tensile stress underneath. The magnitude and direction of this tensile stress is consistent with the crack propagation of a VSR failure. When cracks from the tread surface propagate into this sub-surface axial tensile zone, a VSR can occur under sufficient additional service loading, such as loads caused by in-service wheel/rail impacts from tread damage. Further, softer Class U wheels, removed from service and tested, were found to have a balancing axial tensile stress layer that is deeper below the tread surface than that found in used Class C wheels. This paper describes further efforts to characterize the axial residual stress present in failed VSR and used Class C wheels. Axial residual stress results are obtained near the initiation point of several VSR wheels using x-ray diffraction. Sub-surface axial residual stress patterns are also determined at points of high out-of-roundness for a group of wheels that were tested for TIR (total indicated runout) on the tread surface. Residual stress data and a photo are presented for a wheel rim slice containing a second VSR crack. Additionally, wheel rim ultrasonic testing data, collected by the wheel manufacturer when the wheels were new, are discussed for wheels that have failed due to VSRs and these data are compared to ultrasonic data for non-VSR wheels. Chemistry data are also compared. These data show that the driving force for VSRs is axial residual tensile stress, not a material cleanliness issue.

Development of Railroad Wheel Rim Axial Residual Stress in Heavy Axle Load Service

2013 ◽  
Author(s):  
Cameron Lonsdale ◽  
John Oliver ◽  
Rama Krishna Maram ◽  
Scott Cummings
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Railroad Wheel ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wheel Rim ◽  
Axial Tensile ◽  
Axial Residual Stress ◽  
Class C

Vertical split rim (VSR) failures remain a failure mode for wheels in North America, and are of concern to wheel manufacturers and railroads alike. Both forged and cast wheels have suffered VSRs in service. Extensive testing during the last several years, using x-ray diffraction techniques, has shown the axial residual stress pattern within the railroad wheel rim is significantly different for new AAR Class C wheels vs. AAR Class C wheels that have failed due to a VSR, and non-failed AAR Class C wheels that have been operating in service. VSRs almost always begin at areas of tread damage, resulting from shelling or spalling, and cracking propagates into the rim section under load. At the rim locations tested, the as-manufactured wheels have a relatively “flat” axial residual stress profile, compressive but near neutral, caused by the rim quenching operation, while wheels that have been in service have a layer of high axial compressive stress at the tread surface, and a balancing zone of axial tensile stress underneath. The magnitude and direction of this axial tensile stress is consistent with the crack propagation of a VSR failure. When cracks from tread surface damage propagate into this subsurface axial tensile zone, a VSR can occur under sufficient additional service loading, such as loads caused by in-service wheel/rail impacts from tread damage. Further, softer Class U (untreated) wheels, removed from service and tested, were found to have a balancing axial tensile stress layer deeper below the tread surface than that found in used Class C wheels. This paper describes recent x-ray diffraction testing to measure the axial residual stress profile in wheel rims operated in the Facility for Accelerated Service Testing (FAST) train at the Transportation Technology Center (TTC), in Pueblo, CO. The goal of the testing was to determine the development rate and magnitude of wheel rim axial residual stress, as a function of known load and service mileage. Four new Class C wheelsets and four new Class U wheelsets were placed in service under the FAST train, and these wheelsets were subsequently removed at various mileage levels for evaluation. Two radial rim slices were cut from each wheel at each mileage level, and x-ray diffraction was used to measure the axial residual stress within the wheel rim section. The last two Class C wheelsets and last two Class U wheelsets were also exposed to an extended drag braking event at FAST, where wheel treads were heated by tread braking. The authors describe the testing and discuss the axial residual stress results in detail, with emphasis on implications for service.

Effect of Wheel Truing on Wheel Rim Axial Residual Stress

2013 ◽  
Author(s):  
Cameron Lonsdale ◽  
John Oliver
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
North American ◽  
Service Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wheel Rim ◽  
Axial Residual Stress ◽  
Stress Patterns

Recent x-ray diffraction testing of wheels with machined treads showed that axial residual stresses in the wheel rim were different than the axial residual stresses in Vertical Split Rim (VSR) wheels, and service worn wheels with no machining. As a result, a larger study was conducted at the wheel shops of major North American railroads. Tread damaged wheelsets were machined to remove tread damage and restore the flange/tread profile. The amount of metal removed from the treads was recorded, wheels were demounted, and slices were removed from the machined wheel rims at pre-marked areas for x-ray diffraction testing. The wheel rim axial residual stress patterns for the machined wheels are presented and are compared to the axial residual stress patterns for VSR wheels and used wheels with no machining. Data are presented for both forged and cast wheels. Implications for improved service performance from reduced tread damage are also discussed.

Residual Stress Depth-Profiling in Shot-Peened Al Alloy Components Subjected to Fatigue Testing

2010 ◽  
Vol 638-642 ◽  
pp. 2464-2469 ◽  
Author(s):  
Cristy Leonor Azanza Ricardo ◽  
G. Degan ◽  
M. Bandini ◽  
Paolo Scardi
Keyword(s):  
Residual Stress ◽  
Fatigue Testing ◽  
Depth Profiling ◽  
Cyclic Stress ◽  
Al Alloy ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Stress Profile ◽  
Number Of Cycles

The residual stress profile in a shot-peened Al alloy component was studied by a recently proposed method based on the known procedure of progressive thinning and X-ray Diffraction measurements. The effect the cyclic stress on the fatigue life was studied in detail, showing the correlation between nominal load and residual stress relaxation. Besides showing the expected decrease of compressive stress with the load and number of cycles, the present work highlights the importance of changes in the through-the-thickness residual stress distribution.

Experimental/Modelling Study of Residual Stress in Al/SiCp Bent Bars by Synchrotron XRD and Slitting Eigenstrain Methods

2008 ◽  
Vol 571-572 ◽  
pp. 277-282 ◽  
Author(s):  
Xu Song ◽  
Solène Chardonnet ◽  
Giancarlo Savini ◽  
Shu Yan Zhang ◽  
Willem J.J. Vorster ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Residual Strain ◽  
Numerical Models ◽  
Front Face ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
X Ray ◽  
Residual Stress Profile

The aim of the study presented here was to evaluate the residual stresses present in a bar of aluminium alloy 2124-T1 matrix composite (MMC) reinforced with 25vol% particulate silicon carbide (SiCp) using X-ray diffraction and 3D profilometry (curvature measurement using Mitutoyo/Renishaw coordinate measurement machine) and comparing these results with numerical models of residual strain and stress profiles obtained by a simple inelastic bending model and Finite Element Analysis (FEA). The residual strain distribution was introduced into the test piece by plastic deformation in the 4-point bending configuration. At the first stage of this study the elasticplastic behaviour of the MMC was characterized under static and cyclic loading to obtain the material parameters, hardening proprieties and cyclic hysteresis loops. Subsequently, synchrotron Xray diffraction and CMM curvature measurements were performed to deduce the residual stress profile in the central section of the bar. The experimental data obtained from these measurements were used in the inelastic bending and FEA simulations. The specimens were then subjected to incremental slitting using EDM (electric discharge machining) with continuous back and front face strain gauge monitoring. The X-ray diffraction and incremental slitting results were then analysed using direct and inverse eigenstrain methods. Residual stresses plots obtained by different methods show good agreement with each other.

Wheel Rim Axial Residual Stress and a Proposed Mechanism for Vertical Split Rim Formation

2011 ◽  
Author(s):  
Cameron Lonsdale ◽  
John Oliver
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Axial Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Axial Residual Stress ◽  
Railroad Wheels ◽  
Hoop Stresses ◽  
Future Work

Railroad wheels are manufactured with beneficial residual compressive hoop stresses, which are imparted by rim quenching and tempering. Hoop and radial residual stresses for wheels have been studied in detail by various organizations over the years and are relatively well characterized. However axial residual stresses, in the orientation across the rim width from back rim face to front rim face, have not been extensively investigated. This paper describes a failure mode known as a vertical split rim (VSR) and describes efforts to measure the axial residual stresses in, 1) new wheels, 2) service worn wheels and 3) wheels that have failed from VSRs. Initial axial residual stress measurement efforts, using core drilling and x-ray diffraction from the tread surface, are briefly reviewed. Further more extensive work using x-ray diffraction to measure axial residual stress on radial wheel slices is described and data are presented, focusing on differences between the three wheel types. The concept of Axial Stress Amplification (ASA) is outlined, and the relationship of axial residual stress to VSRs is discussed. A proposed mechanism for VSR formation is described. Future work, with a goal of reducing or eliminating VSRs in service, is considered.

Through Thickness Residual Stress Measurements by Neutron Diffraction and Hole Drilling in a Single Laser-Peened Spot on a Thin Aluminium Plate

2013 ◽  
Vol 772 ◽  
pp. 167-172 ◽  
Author(s):  
M. Burak Toparli ◽  
Michael E. Fitzpatrick
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Diffraction Peak ◽  
Thin Plates ◽  
Hole Drilling ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stress Measurements ◽  
Incremental Hole Drilling

Residual stress measurements are very challenging in thin aluminium plates. Rolling-induced crystallographic texture can lead to an S-shape fit when using the sin2ψ method for surface X-ray diffraction. Peak broadening and missing peaks can also be observed for synchrotron X-ray diffraction with conventional θ/2θ scanning due to texture. In addition, when measuring near the plate surfaces, partially-filled gauge volumes in diffraction experiments will lead to “pseudo-strains”, an apparent shift between measured and actual positions for the diffraction peak. Obtaining a meaningful value of d0 for strain calculations is another issue for diffraction experiments in thin plates. The low thickness also offers challenges for destructive methods including incremental hole drilling, i.e. there is no defined ASTM standard for measuring non-uniform residual stress profile for thin plates. In this work, 2-mm-thick Al2024-T351 plate was investigated for residual stress fields due to laser peening. Neutron diffraction measurements were carried out at POLDI (Pulse Overlap time-of-flight Diffractometer) in PSI, Switzerland and the results are compared with incremental hole drilling.

Residual Stress in GaAs Layer Grown on 4°-Off (100)Si by MBE

1987 ◽  
Vol 91 ◽  
Author(s):  
T. Yao ◽  
Y. Okada ◽  
H. Kawanami ◽  
S. Matsui ◽  
A. Imagawa ◽  
...  
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Gaas Layer ◽  
Residual Tensile Stress ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Misfit Stress ◽  
Si Substrates ◽  
Gaas Films ◽  
Semiconductor Laser Diodes

ABSTRACTResidual stress in molecular beam epitaxially (MBE) grown GaAs films on 4°-off (100)Si substrates is investigated with X-ray diffraction technique. It is experimentally confirmed that the GaAs lattice suffers tetragonal deformation with the c-axis being [100]. The GaAs lattice tilts by approximately 0.2° towards the tilted direction of the substrate. It is found that two-dimensional compressive stress dominates in GaAs films thinner than 0.3 μm in thickness, while two-dimensional tensile stress dominates in thicker films. The variation of the stress is understood in terms of a combination of misfit stress and thermal stress. The residual tensile stress is larger than 1 × 109 dyn/cm2 in the films thicker than I pm. The effect of the stress on the reliability of semiconductor laser diodes is discussed.

scholarly journals Investigations on Residual Stresses within Hot-Bulk-Formed Components Using Process Simulation and the Contour Method

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 566
Author(s):  
Bernd-Arno Behrens ◽  
Jens Gibmeier ◽  
Kai Brunotte ◽  
Hendrik Wester ◽  
Nicola Simon ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Process Simulation ◽  
Hot Forming ◽  
Contour Method ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
Forming Process ◽  
Near Surface ◽  
X Ray

Residual stresses resulting from hot-forming processes represent an important aspect of a component’s performance and service life. Considering the whole process chain of hot forming, the integrated heat treatment provided by a defined temperature profile during cooling offers a great potential for the targeted adjustment of the desired residual stress state. Finite element (FE) simulation is a powerful tool for virtual process design aimed at generating a beneficial residual stress profile. The validation of these FE models is typically carried out on the basis of individual surface points, as these are accessible through methods like X-ray diffraction, hole-drilling, or the nanoindentation method. However, especially in bulk forming components, it is important to evaluate the quality of the model based on residual stress data from the volume. For these reasons, in this paper, an FE model which was already validated by near surface X-ray diffraction analyses was used to explain the development of residual stresses in a reference hot forming process for different cooling scenarios. Subsequently, the reference process scenarios were experimentally performed, and the resulting residual stress distributions in the cross-section of the bulk specimens were determined by means of the contour method. These data were used to further validate the numerical simulation of the hot forming process, wherein a good agreement between the contour method and process simulation was observed.

scholarly journals A synchrotron X-ray diffraction deconvolution method for the measurement of residual stress in thermal barrier coatings as a function of depth

2016 ◽  
Vol 49 (6) ◽  
pp. 1904-1911 ◽  
Author(s):  
C. Li ◽  
S. D. M. Jacques ◽  
Y. Chen ◽  
D. Daisenberger ◽  
P. Xiao ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Barrier ◽  
Stress Profile ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barrier Coating ◽  
Average Residual ◽  
Diffraction Patterns ◽  
Plasma Sprayed

The average residual stress distribution as a function of depth in an air plasma-sprayed yttria stabilized zirconia top coat used in thermal barrier coating (TBC) systems was measured using synchrotron radiation X-ray diffraction in reflection geometry on station I15 at Diamond Light Source, UK, employing a series of incidence angles. The stress values were calculated from data deconvoluted from diffraction patterns collected at increasing depths. The stress was found to be compressive through the thickness of the TBC and a fluctuation in the trend of the stress profile was indicated in some samples. Typically this fluctuation was observed to increase from the surface to the middle of the coating, decrease a little and then increase again towards the interface. The stress at the interface region was observed to be around 300 MPa, which agrees well with the reported values. The trend of the observed residual stress was found to be related to the crack distribution in the samples, in particular a large crack propagating from the middle of the coating. The method shows promise for the development of a nondestructive test for as-manufactured samples.

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