On the Source of the Systematic Error of the Pressure Measurement Film Applied to Wheel–Rail Normal Contact Measurements

Lekue, Jagoba; Dörner, Florian; Schindler, Christian

doi:10.1115/1.4037358

Cited by 9 publications

(15 citation statements)

References 7 publications

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“…Alternatively, a conventional material model can be assigned to the elements by defining a constitutive law [31], as done in this work. The finite element model employed so far to replicate the Hertzian experiments conducted in the laboratory [26,27] was accordingly adapted for the material calibration procedure as depicted in Fig. 1.…”

Section: Film Model Calibrationmentioning

confidence: 99%

“…The finely meshed film model used in previous studies, however, was considerably simplified into a single layer of gasket elements. The thickness dimension was set to 90 lm based on experimental observations [26] and a radial dimension of 100 lm was defined for each element so as to match the measurement resolution [33]. The bottom nodes of the flat body were vertically constrained and the normal force was introduced as pressure on the spherical body.…”

Section: Film Model Calibrationmentioning

confidence: 99%

“…Subsequent considerations concerning the mechanical alteration caused by the presence of Prescale film between contact surfaces shed light on the dependence of measurement error and roughness sensitivity on the film type. By generating detailed finite element models of the Hertzian experiments including the film, a relation between measurement error and capsule size (and thus film type) could be established [26]. Furthermore, microscopic roughness was implemented in the macroscopic models of the experiments in order to demonstrate that the lack of sensitivity of HHS films to roughness variations is perfectly consistent with the governing contact mechanics [27].…”

Section: Introductionmentioning

confidence: 99%

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Calibration of a finite element model of Prescale film for wheel-rail normal contact area measurements

2021

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This article presents the latest of a series of research activities aimed to determine the deviation originated when Prescale pressure measurement film is used to measure the size and shape of the wheel-rail contact area. Despite being an attractive solution due to the simplicity of the measurement procedure, it is well known that the contact interaction is altered by the presence of the film. Consequently, characterizing and filtering out the systematic measurement error is a fundamental requirement for accurate quantitative assessments. Nevertheless, the complexity of the wheel-rail contact problem, which lacks an analytical solution, hinders the direct determination of correction values. The approach presented here builds on error corrections for simpler Hertzian geometries to calibrate a film model for further use in the wheel-rail contact scenario. The results highlight the marked dependency of the measurement error on wheel and rail roughness and underline the importance of including the film into finite element models that are validated by comparison with experimental observations.

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Section: Film Model Calibrationmentioning

confidence: 99%

Section: Film Model Calibrationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Calibration of a finite element model of Prescale film for wheel-rail normal contact area measurements

2021

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“…45 Further investigations about the systematic error of pressure measurement film can be found in numerous resources. 45,46,74 Comparison of ultrasonic testing with FEA Zhou et al 24 reported about ultrasonic measurements with a full wheel and an edited rail to place an ultrasonic scanning array. They carried out various tests with different loads and different rolling speeds (max 5 mm/s).…”

Section: Comparison Of Pressure Measurement Film With Fea And/ or Hertzmentioning

confidence: 99%

Overview of methods to identify the static normal wheel-rail contact

Stratmann

Goersch

Schindler

2021

Proceedings of the Institution of Mechanical Engineers, Part F:

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Determining the shape and size of a wheel-rail contact area is required to calculate fatigue and wear of wheel and rail. Fatigue and wear are influenced by high pressures of up to 1000 MPa that act on the small contact area of approximately 1 cm². One problem in identifying the contact patch is the inaccessibility of the contact point. Therefore, numerical and experimental methods have been applied to identify the shape and size of the contact area in the static wheel-rail contact. Here, we summarize and compare methods to identify the static wheel-rail contact area, in particular the Hertzian calculation, the use of carbon paper, the use of pressure measurement film, the finite element method, the use of ultrasonic testing, and a semi-Hertzian method called STRIPES. Our review revealed that several methods exist to determine the static wheel-rail contact, which were introduced as well as results of some research projects. However, the partly incomplete description of methods studied impeded a detailed assessment of the results. Furthermore, due to the non-comparable parameters applied in the different studies, it was impossible to contrast the results and methods presented in the different publications. Hence, it is recommended that future results in the field of static wheel-rail contact should be directly contrasted with a detailed finite element model. This proceeding will allow to directly compare different methods on the bases of finite element analysis and thus the identification of a method for each situation.

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“…In the experimental research, some experimental methods were applied to measure the contact pressure distribution, such as a Tekscan pressure sensor [8] and a prescale measurement film [9,10]. However, these experimental methods must insert a thin film between the contacting bodies, which is a cause of measurement error.…”

Section: Introductionmentioning

confidence: 99%

Experimental and simulation analyses of the stress field of slider-on-block contact for static and slip states

et al. 2020

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Contact problems have been widely investigated for many years. However, there are few reports on the real-time observation of shear stress evolution in friction process by experimental method. In this paper, the plane stress fields of slider-on-block contact in different contact states were observed by photoelasticity experiments and finite element simulation. In the static state, the slider is only subjected to a normal force by an L-shaped body above the slider while the block is fixed. However, in the slip state, the block is moved, and the slider is acted upon by normal and tangential forces. In both cases, the principal stress difference fields in the block obtained by photoelasticity and simulation were basically consistent. Additionally, based on simulation, the distributions of pressure and frictional stress on the contact surface were determined; the influences of the load and friction coefficient on the contact stress distributions were also investigated. Accordingly, some principles for contact stress distribution were obtained. The combination of experimental and simulation methods aims to be complementary, helping to better understand the nature of the contact stress field.

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On the Source of the Systematic Error of the Pressure Measurement Film Applied to Wheel–Rail Normal Contact Measurements

Cited by 9 publications

References 7 publications

Calibration of a finite element model of Prescale film for wheel-rail normal contact area measurements

Calibration of a finite element model of Prescale film for wheel-rail normal contact area measurements

Overview of methods to identify the static normal wheel-rail contact

Experimental and simulation analyses of the stress field of slider-on-block contact for static and slip states

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