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1

Assessment of fatigue life of aluminized, coarse-grained MAR247 alloy supported by full-field ESPI measurements

Kopec Mateusz, Kukla Dominik, Kowalewski Zbigniew L.

Journal of Theoretical and Applied Mechanics

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2022

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Vol. 60 nr 4

619--623

EN

In this paper, fatigue performance of an aluminide layer coated, coarse-grained MAR247 nickel superalloy was monitored by using the full-field Electronic Speckle Pattern Interferometry (ESPI) method in the range of stress amplitude from 350MPa to 650MPa. It was found, that the ESPI method enables precise monitoring of the fatigue behaviour of coated MAR247 specimens since the area of potential failure was accurately indicated within the initial stage of fatigue damage development.

2

The stress and strain distribution in X10CrMoVNb9-1 power engineering steel after long time degradation studied by the ESPI system

Kopec Mateusz

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 3

art. no. e141181

EN

Maintenance of assets and equipment in power plants is essential for their safety and is required to help the plant stay active. In this paper, the specimens manufactured from a pipe of X10CrMoVNb9-1 (P91) power engineering steel in the as-received state and after operating for 80 000 h at internal pressure of 8.4 MPa and temperature of 540ºC were subjected to tests using electronic speckle pattern interferometry (ESPI) under static loading of up to 2.5 kN. Such a procedure enables assessment of strain and stress distribution maps to compare material integrity in the as-received state and after exploitation in its elastic range. The measurements conducted showed no effect of long time operation on the mechanical response of P91 steel under the power installations conditions since the field strain distributions for each type of specimen were found to be similar.

3

Application of Electronic Speckle Pattern Interferometry for Evaluation of the Static Stiffness of a Complex Orthopedic Implant

Mrozek Piotr, Borkowski Piotr

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 2

39--48p.borkowski@pb.edu.pl

EN

The paper presents a comparative analysis of the results of experimental and numerical evaluation of static stiffness of extendable tumor knee joint prosthesis for children. Electronic speckle pattern interferometry and finite element method were used for experimental and computational research, respectively. The procedure of experimental tests shows that the stiffness of the joint prosthesis can be determined experimentally by means of electronic speckle pattern interferometry, but the quantitative result of such a procedure cannot be captured directly in a finite element method model. The values of static stiffness calculated numerically do not fall within the range of experimental results. The discrepancy grows as the extension of the endoprosthesis increases and the value of relative difference between numerical and experimental results reaches the value of 54%. The inconsistency of results can be explained by the involvement of the joint linking the body of the implant to the moving part. While effective in the case of traditional, one-piece constructions, finite element method modeling does not yield satisfactory results in the case of such an elementary parameter as is the static stiffness of the implant, due to the difficulty in estimating the stiffness of the joint present in the sliding node. The use of the experimental method makes it possible to estimate the degree of this inconsistency.

4

Evaluation of the fatigue damage development using ESPI method

Kopeć M., Grzywna P., Kukla D., Kowalewski Z.

Inżynieria Materiałowa

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2016

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Vol. 37, nr 4

201--205

EN

Fatigue damage process developing in structural materials under long-term cyclic loading is still an unsolved problem of modern engineering. Attempts to assess a degree of materials degradation under fatigue conditions on the basis of changes in the areas of local strain concentration determined by optical methods can be treated as the promising contemporary research direction of majority of scientific centres in the world. In most cases, fatigue damage has a local character and it is based on damage development leading to generation of cracks appearing around structural defects or geometrical notches. An identification of these areas and their subsequent monitoring requires a full-field displacement measurements performed on the objects surfaces. It seems that modern contemporary optical methods for displacement components measuring on the surfaces of structural elements or tested specimens are suitable for such purpose. Digital Image Correlation (DIC) and Electronic Speckle Pattern Interferometry (ESPI) are nowadays the most widely used testing methods in this area. Both of them enable capturing of displacement and strain components distributions. This paper presents an attempt to use the ESPI method for fatigue damage evaluation and its monitoring on specimens made of the aluminide coated nickel super-alloys. Flat specimens were subjected to cyclic loading. The fatigue tests were interrupted several times in order to perform a static loading during which the optical measurements were carried out. An analysis of the results captured by the ESPI system allowed indication of places of the greatest stress concentration and demonstration of the damage development process as a function of the increasing number of cycles.

PL

Proces niszczenia materiału w trakcie badań zmęczeniowych pod wpływem długotrwałych obciążeń eksploatacyjnych od lat pozostaje jednym z głównych problemów poruszanych przez wiele ośrodków badawczych na świecie. W większości przypadków zmęczenie materiału wykazuje lokalny charakter prowadzący do powstawania pęknięć występujących wokół defektów struktury czy karbów geometrycznych. Identyfikacja tych obszarów i ich późniejsza obserwacja wymagają użycia polowych technik pomiarowych takich jak cyfrowa korelacja obrazu (Digital Image Correlation, DIC) lub elektroniczna interferometria plamkowa (Electronic Speckle Pattern Interferometry, ESPI). Pozwalają one określać rozkłady składowych przemieszczenia, odkształcenia i naprężenia na powierzchni próbki (rys. 1). Stosowanie ich w trakcie badań zmęczeniowych umożliwia lokalizację miejsca największej koncentracji naprężenia wywołanej defektami próbek oraz pozwala z dużą dokładnością przewidzieć miejsce inicjacji uszkodzenia. Celem pracy jest obserwacja i analiza rozwoju pękania zmęczeniowego wywołanego długotrwałymi, cyklicznymi obciążeniami za pomocą optycznej metody pomiaru składowych przemieszczenia ESPI.

5

Evaluation of strain distribution for the P91 steel under static load using espi system

Grzywna P., Kukla D.

Advances in Materials Science

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2014

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Vol. 14, nr 4(42)

28--39

EN

The goal of the research was to evaluate the change of displacement/strain phases in the P91 steel under static load conditions. Undertaken tests were aimed at estimation and analysis of the impact of the material state, which was subjected to loading conditions, on the distribution of stress pattern using ESPI system. Specimen made of high temperature creep resistant steel X10CrMoVNb9-1 (P91) used as a construction material for boiler steam feed heaters, vapor tanks, pressure vessels and vapor pipelines, is used in the service conditions of temperature range up of 650°C. Test samples were taken from two P91 steel pipes. One sample came from a segment of a pipeline transporting fresh vapor in time 80 000 h, under the pressure of 8.4 MPa and temperature 540 °C. The second sample was the same material but in the delivery state.

6

Pomiary i analiza naprężeń resztkowych w stopie tytanu Ti6Al5 z zastosowaniem elektronicznej interferometrii plamkowej (ESPI)

Tomkowski R., Lipiński D., Kacalak W.

Pomiary Automatyka Kontrola

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2013

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R. 59, nr 11

1223--1226

PL

Naprężenia resztkowe wpływają między innymi na takie właściwości eksploatacyjne części maszyn, jak odkształcenie, wytrzymałość statyczna i dynamiczna, zużycie materiału, czy też wytrzymałość stykowa. Zastosowanie elektronicznej interferometrii plamkowej do pomiarów naprężeń resztkowych umożliwia wyeliminowanie problemów, które występują w standardowej metodzie tensometrycznej tj. pozycjonowanie wiertła względem rozety tensometrycznej, czy też zdeterminowana liczba kierunków pomiaru naprężeń. W pracy przedstawiono zagadnienia związane z pomiarami naprężeń resztkowych z zastosowaniem elektronicznej interferencji plamkowej (ESPI), stopu tytanu Ti6Al5 (TitanGrade 5) po obróbce ściernej, z zastosowaniem systemu Prism firmy Stresstech Oy.

EN

Residual stresses influence, among other parameters, on the performance characteristics of the machine, such as deformation, static and dynamic strength, material usage, or the strength of the contact. Extensional stresses as a result of abrasive machining reduce the fatigue strength for the dynamically loaded machine parts. It is preferred when the surface layer of the compressive stress is obtained. Therefore, it is recommended to reduce or remove most of the tensile stresses in the elements of the machine, for example, by reducing the value of technological parameters (feed-in). Note also that the type of occurring stresses depends also on the characteristics of the used grinding wheel, where the importance has the type of selected abrasive material. Grinding, eg. grinding wheel with aloxite grain is almost always the occurrence of tensile stresses, in contrast to CBN, which causes the formation of an compressive stresses in the surface layer. The article presents the issues related to the measurement of residual stresses by using electronic speckle pattern interference (ESPI), titanium alloy Ti6Al5 (TitanGrade 5), using a system of Stresstech Prism Oy. Stress measurements using ESPI can eliminate the problems that exist in the strain-gage method, such as the positioning of the axis of the drill in the center of the rosette hole, and only three directions of stress measurement (every 120 degrees). In the ESPI method stresses are recorded in all directions per-pendicular to the axis of the hole.

7

Numerical and experimental method in biomechanics

Będzinski R.

Vibrations in Physical Systems

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2008

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Vol. 23

25--33

EN

The analysis of the effort of structural components by calculation methods often encounters serious difficulties. Usually, aim of biomechanical research is determination displacement distribution of anatomical samples or physical models. Development of modern numerical method and computational techniques into field of biomechanics in recent years allow to solve highly complex problems encountered in the assessment of the strength and reliability of bone structures and implants. But they usually require experimentally determined boundary conditions or courses of the involved phenomena.