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1

Fatigue damage development in 10CrMo9-10 steel for power plant pipes in as-received state and after 280,000 h of exploitation

Kopec Mateusz, Brodecki Adam, Kowalewski Zbigniew L.

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e98, 2023

EN

This paper discusses an effect of 280,000 h of exploitation under internal pressure of 2.9 MPa and high temperature of 540 °C on the mechanical properties of 10CrMo9-10 (10H2M) power engineering steel. The mechanical response of the specimens obtained from two pipes: a new in the as-received state and exploited for a long period was assessed through the uniaxial tensile tests and subsequent fatigue tests. The long-term, high-temperature exposure of 10H2M steel resulted in the deterioration of its mechanical properties and was quantitatively described as a function of the fatigue damage measure, φ, and the fatigue damage parameter D. Finally, the proposed methodology of power exponent approximation with both damage sensitive parameters (φ, D) enabled for successful determination of the 10H2M steel fatigue life.

2

Experimental study on fatigue failure evolution in composite plate monitored by wave propagation method

Stawiarski Adam, Barski Marek, Muc Aleksander

Vibrations in Physical Systems

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2020

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Vol. 31, nr 2

art. no. 2020227

EN

In this study, the elastic wave propagation method is used to observe the initiation and evolution of the fatigue failure form in the multilayered composite plate with an elliptical hole. The experimental tests with the use of active, pitch-catch elastic wave measurement techniques are used during the fatigue test of the composite specimens. The fatigue tests were preceded by the numerical, finite element analysis of the elastic wave propagation phenomenon in a composite plate with an elliptical hole. The sequential measurement related to the number of cycles during the fatigue tests was assumed. The time of flight (ToF) and amplitude change was monitored by piezoelectric sensors localized in the area of predictable failure form evolution. The analysis of the dynamic response of the structure under fatigue loading conditions by a relatively small number of piezoelectric transduces allows us to build cost-effective Structural Health Monitoring (SHM) system for damage detection and monitoring of the failure form evolution.

3

Application of X-ray tomography to assess fatigue structural changes in asphalt mixtures

Mackiewicz Piotr, Szydło A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2019

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Vol. 67, nr 2

307--315

EN

The article presents an analysis of the change in air voids in asphalt mixtures subjected to fatigue tests at three temperatures of 0°C, 10°C and 25°C. The X-ray computerized tomography imaging method, XCT, was used to identify the air voids in the samples. The research allowed to determine changes in the content of air voids in subsequent fatigue cycles in the sample area. The relationship between air voids volume and the stiffness modulus value was also determined during fatigue for three temperatures. The largest changes were found in samples with notches at 0°C. The analysis of the change in the content of air voids showed that the micro-cracking nucleation processes develop with the number of fatigue cycles. Using the numerical model finite element method we determined the distribution and change in fatigue damage in the extreme areas of the sample during various stages of fatigue. We found clear relationship between the damage and the increased content of air voids.

4

Simplified estimate of fatigue damage based on dynamic analysis

Dekys V., Kriska P, Lietava L., Kopas P., Stalmach O.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2018

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z. 99

15--23

EN

The article presents a procedure for vibration analysis of the device based on measured data in simulated operating modes. Subsequently, the criterion of fatigue damage is formulated because this mechanism can be induced or accelerated by recognized operating deflection shapes. The criterion is used to select an optimal set of control device parameter values, which control each device’s operating modes and transitions between these modes and affect the excitation of the frame vibration due to possible shocks in the system. The criterion is formulated based on the vibration displacement processing from these dynamic measurements, the modified Goodman and Palmgren-Miner rules, and the results of static computational analyse. This criterion compares the effect of damage to the modes that control these sets of parameters, while the selection of the optimal control set is performed. At the end of the article, the limitations resulting from the simplifications used are described. The application of this procedure is also useful, for example, when further data are obtained by subsequent experimental stress-strain analysis methods and when we want to reduce the number of possible operating modes by which we carry out subsequent measurements among the most damaging modes.

5

Effective algorithm for structural optimization subjected to fatigue damage and random excitation

Sága M., Vaško M., Ságová Z., Handrik M.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2018

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z. 99

149--161

EN

The aim of the paper is to present the computationally timeconsuming task of simulating the process of randomly oscillating thin-shell structures to realize an optimal design with limitations in terms of fatigue damage. The most important aim here is to design an effective optimization algorithm and choose an appropriate approach for the evaluation of multiaxial fatigue damage in the context of the random and non-proportional character of stress in the structure when considering the standard finite element model. The authors propose their own optimization algorithm, which is described in the present study and, on the basis of tests, has proven to be suitable for the aforementioned technical problems. The proposition of algorithms for calculating the accumulation of fatigue damage in non-proportional and multiaxial stresses (especially in terms of the application of rainflow analysis by decomposition of the equivalent stress, as determined by the appropriate “fatigue” criterion) is very important in such computational processes. The entire computational process was implemented in MATLAB with the “Discret_Opt_Fat” main control program. The article presents the theoretical basis for the presented complex problem solution, its algorithmization and the technical application.

6

Kumulacja uszkodzeń zmęczeniowych stopu aluminium 6082-T6 w warunkach blokowego skręcania

Böhm E., Kurek M., Łagoda T.

Transport Przemysłowy i Maszyny Robocze

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2017

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Nr 4

58--61

PL

Pęknięcia zmęczeniowe elementów maszyn i urządzeń pod wpływem obciążeń eksploatacyjnych zachodzą najczęściej w warunkach losowych lub zmienno amplitudowych obciążeń. W literaturze występuje bardzo duża liczba opracowanych modeli hipotez zmęczeniowych, zarówno w ujęciu naprężeniowym, odkształceniowym, jak i energetycznym. Najszersze zastosowanie oraz zakres weryfikacji mają hipotezy liniowe o stosunkowo prostym zapisie, pozwalającym na ich pewne modyfikacje.

EN

The paper presents results of experimental research of aluminum alloy 6082-T6 (PA4) under block-type loads. Fatigue testing was performed on the MZGS-100 stand under blocks torsion. The main aim of this paper is present and compare damage accumulation calculations using the hypothesis Palmgrena-Minera and authors model. A new model is based on material memory.

7

Development of a design-experimental methodology for the prediction of reliable exploitation of freight railway cars

Voropai V.

Transport Problems

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2017

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T. 12, z. 3

21--34

EN

The article is devoted to the front burner problem of effective exploitation of industrial tank-wagons with the presence of residual operation time. The procedure of valuation of tank-cars’ residual operation time for liquid gas transportation was proposed first. Key technical and exploitation parameters of the tank-wagon model 15-1408-10 according to testing loads that simulate loads in real exploitation were approved. The calculation, which, as against existent ones for valuation of universal freight cars’ residual operation time, allows to calculate equivalent stress using test results that rely on a change of internal pressure activity during drainage and filling operations, and the most unfavorable combination of simulation of active loads on a tank-wagon was proposed. The proposed procedure can be adapted for use during valuation of freight cars’ residual operation time, or for other means of transport and machineries.

8

Evaluation of fatigue life calculation algorithm of the multiaxial stress-based concept applied to S355 steel under bending and torsion

Macek W., Mucha N.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 4

935--951

EN

This paper presents the results of a study into the stress-based fatigue life calculation algorithm applied to cyclic and random multiaxial proportional and non-proportional loading. This method for high-cycle fatigue, covers both infinite and finite life region, and is based on a critical plane approach combined with rain flow cycle counting and linear damage accumulation. Algorithm based on the method for equivalent scaling of the normal stress in material planes in dependence on the stress state, proposed by Gaier and Danbauer. For analysis the calculated fatigue lives are compared to the experimental results for steel S355 under proportional and non-proportional bending with torsion.

9

Derived equations for damage accumulation in geared wheels based on modified laws of crack propagation

Drewniak J., Rysiński J.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2016

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z. 91

19--31

EN

Versatile hypotheses of fatigue damage accumulation are utilized in order to determine the fatigue life of particular mechanical elements. Such an approach to an analysis of fatigue processes is recognized as being phenomenological. In the present paper, modifications to the Paris and Foreman laws of fracture mechanics have been proposed. The goal of these modifications is an explicit formulation of crack propagation velocity as a function of crack length. Additionally, the process of crack growth was simulated according to the Palmgren-Miner and Pugno-Ciavarella-Cornetti-Carpinteri fatigue hypotheses. The results of simulation were verified based upon test stand experiments.

10

Autonomous online system for evaluating steel structure durability

Mantič M., Kuľka J., Faltinová E., Kopas M.

Diagnostyka

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2016

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Vol. 17, No. 3

15--20

EN

The article deals with the design of equipment and its application possibilities for on-line monitoring of operational stress traverse mechanisms. By processing of load spectra it is possible to predict the remaining life in the selected areas of the construction.

11

Fatigue damage detection in composite plate with a circular hole by elastic wave propagation method

Stawiarski A., Miarka S., Barski M., Romanowicz P.

Composites Theory and Practice

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2016

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R. 16, nr 1

20--24

EN

In this study, the elastic wave propagation phenomenon was used to detect the initiation of fatigue damage in a composite plate with a circular hole. The Structural Health Monitoring (SHM) system based on the active pitch-catch measurement technique was proposed. Two configurations of measuring points location were taken into account. The signals from the intact structure were compared with the dynamic response from a structure having a relatively small, interlaminar defect. The influence of the measuring points (actuators and sensors) location on the effectiveness of the damage detection method was performed to obtain an efficient system which can detect the initiation of fatigue damage in a composite plate with a circular hole.

PL

W pracy wykorzystano metodę propagacji fal sprężystych do wykrywania inicjacji uszkodzeń zmęczeniowych w kompozytowej płycie z otworem. Zaproponowano system SHM (Structural Health Monitoring) oparty na aktywnej, transmisyjno-odbiorczej technice pomiarowej. Uwzględniono dwie konfiguracje rozmieszczenia punktów pomiarowych. Sygnały pochodzące ze struktury wzorcowej porównano z dynamiczną odpowiedzią płyty zawierającej stosunkowo niewielki, międzywarstwowy defekt. Określono wpływ lokalizacji punktów pomiarowych (aktywatorów i sensorów) na skuteczność metody detekcji w celu uzyskania efektywnego systemu umożliwiającego wykrycie inicjacji uszkodzenia zmęczeniowego w kompozytowej płycie z otworem.

12

Kumulacja uszkodzeń zmęczeniowych dla obciążeń blokowych z wykorzystaniem pamięci materiału

Böhm E.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2015

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z. 105

21-22

EN

The paper presents a new model to calculate the degree of fatigue damage. It is based on the memory of the material. The model is verified on the basis of the block loads (High-Low, Low-High).

13

Modelowanie wpływu niesymetrycznych dwu-blokowych obciążeń na kumulację uszkodzeń zmęczeniowych w stali EN295

Gołoś K., Gołoś A.

TTS Technika Transportu Szynowego

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2015

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R. 22, nr 12

568--571, CD

PL

W artykule przedstawiono wyniki badań doświadczalnych kumulacji uszkodzeń zmęczeniowych przy cyklicznych dwu-blokowych sekwencjach obciążenia dla cykli symetrycznych i z dodatnim odkształceniem średnim cyklu dla stali En 295. Do analizy danych doświadczalnych oprócz liniowej hipotezy Palmgrena-Minera została wykorzystana również hipoteza Gołosia-Ellyina. Porównanie wyników doświadczalnych i analitycznych wykazało dość dobrą zgodność.

EN

The results of experimental studies of fatigue damage accumulation at the cyclic two-block sequence loading for steel En295 have been presented Studies have shown load sequence effect on fatigue damage accumulation process for the test steel. In the descending load values in a block (H-L) summed linearly measure of accumulation was in the range of 0, 65 to 0.94. If the reverse order of blocks (L-H) linearly summed measure of the accumulation ranged from 1.02 to 1.25. Positive mean strain generally decreases the fatigue life. For the analysis of experimental data in addition to the linear hypothesis Palmgren-Miner has been used a hypothesis put forward by Golos and Ellyin. Predictions based on the analyzed hypothesis for the analyzed test load sequence for symmetrical and with mean strain cycles for steel specimen En295 compared with the data obtained showed good agreement.

14

Wpływ eksploatacji na wybrane właściwości mechaniczne stali X10CrMoVnB9-1 (P91)

Grzywna P., Kukla D.

Przegląd Spawalnictwa

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2013

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R. 85, nr 12

75--77

PL

Przedstawienie wyników badań stali P91 w stanie dostawy i po 80 000 h przepracowanych na rurociągu pary świeżej oraz wskazanie parametrów porównawczych stanowi treść niniejszego opracowania. W pracy przedstawione zostały wyniki badań składu chemicznego, mikrostruktury, statycznej próby rozciągania oraz charakterystyki Wöhlera. Nawiązano też do wyników badań nieniszczących otrzymanych przy użyciu metody prądów wirowych umożliwiających ilościową ocenę stopnia degradacji zmęczeniowej stali P91.

EN

Tests results of P91 steel taken from a scrap of a new pipeline and a pipeline after 80 000 h of its exploitation in real steam conditions were presented. Additionally, in the present paper comparative parameters were indicated. Chemical composition analysis, microstructural observations, static tensile tests were carried out; also Wöhler’s characteristics were outlined. Moreover, there were considered results of nondestructive methods such us eddy currents that allow quantitative assessment of fatigue damage evolution of P91 steel.

15

Problemy uszkodzeń zmęczeniowych osi pojazdów szynowych

Ładecki B., Skowronek T.

Przegląd Spawalnictwa

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2013

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R. 85, nr 12

97--100

PL

Pomimo projektowania osi pojazdów szynowych w zakresie tzw. nieograniczonej wytrzymałości zmęczeniowej, wobec podwyższania prędkości pojazdów oraz występowania złożonych zjawisk eksploatacyjnych i materiałowych, rejestrowane są kolejne przypadki występowania uszkodzeń takich osi. W artykule przedstawiono wyniki badań nieniszczących 120 szt. osi pojazdów szynowych, dla których po ok. 4 latach eksploatacji, dla 8 szt. osi stwierdzono występowanie pęknięć zmęczeniowych. Badania defektoskopowe wykonane metodami ultradźwiękową i magnetyczno-proszkową pozwoliły wytypować element, z którego pobrano próbki do wykonania badań składu chemicznego materiału, pomiarów twardości, badań mikroskopowych i fraktograficznych. Analiza uzyskanych wyników badań wykazała, że przyczyną wykrytych pęknięć zmęczeniowych osi było powstanie pęknięć hartowniczych w obszarze karbu geometrycznego.

EN

Despite axis design of rail vehicles for so-called unlimited fatigue strength, towards increase of the speed of vehicles and occurrence of a number of operational and materials complex phenomena, more cases of damages to such axis are recorded. This article presents the results of non-destructive testing of 120 pcs of axis of rail vehicles, for which after about four years of operation, for eight pieces of axis fatigue cracks were found. Completed nondestructive examination, using ultrasonic and magnetic-particle methods, helped predict the element from which were taken samples for testing the material chemical composition, hardness measurements, microscopic and fractographic examination. Analysis of the tests results showed that the cause of detected fatigue cracks of axis were quenching cracks arisen in the notch geometry.

16

Identyfikacja uszkodzenia zmęczeniowego stopu aluminium 2017 na podstawie pomiarów konduktywności

Kukla D., Szlagowska-Spychalska J., Grzywna P., Zagórski A.

Przegląd Spawalnictwa

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2013

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R. 85, nr 12

88--91

PL

Zaprezentowane badania skupiały się na ocenie możliwości wykorzystania pomiarów konduktywności do identyfikacji i lokalizacji uszkodzenia zmęczeniowego w próbkach ze stopu aluminium 2017. Monitorowanie zmian przewodności w wybranych punktach próbki po kolejnych cyklach obciążeń rozciągających pozwoliło stwierdzić spadek tego parametru w miejscu powstania i rozwoju uszkodzenia, prowadzącego do pęknięcia próbki. Istotne zmiany przewodności występują w ostatnim etapie zmęczenia i są związane prawdopodobnie z lokalnym odkształceniem plastycznym towarzyszącym rozwojowi pęknięcia dominującego. Testy prowadzono na próbkach wyciętych z blachy walcowanej o grubości 1, 2 i 3 mm poddanych cyklicznym obciążeniom rozciągającym. Pomiar konduktywności realizowany był kilkakrotnie, po zadanej sekwencji cykli, w siedmiu miejscach po obu stronach próbki, co umożliwiło na lokalizację uszkodzenia zmęczeniowego.

EN

The research have focused on the use of conductivity measurements to the identification and location of fatigue failure in the aluminum alloy 2017 samples. Monitoring changes in conductivity at selected points of the samples, following subsequent tensile load, have revealed the decrease in conductivity in place of the initiation and development of damage, before the cracks sample. Significant changes in conductivity occur in the last stage and the associated fatigue are likely to be a local plastic deformation accompanying the development of cracks dominant. Tests performed on samples cut from the rolled sheet with a thickness of 1, 2 and 3 mm treated with a cyclic tensile stress. Conductivity was carried out several times, the key sequence cycles in seven locations on both sides of the sample, allowing the location of fatigue damage.

17

Analiza sygnałów emisji akustycznej do wykrywania uszkodzeń zmęczeniowych w stali okrętowej

Baran I., Nowak M., Schmidt J.

Przegląd Spawalnictwa

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2013

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R. 85, nr 5

2--7

PL

Uszkodzenia korozyjne i pęknięcia zmęczeniowe to główne przyczyny awarii konstrukcji wszelkich środków transportu, takich jak statki (tankowce), autocysterny i cysterny kolejowe. Oba rodzaje degradacji zarówno materiału, jak i konstrukcji są przedmiotem badań w projekcie realizowanym w ramach VII kooperacyjnego programu ramowego UE (Transport) pt. Cost effective corrosion and fatigue monitoring for transport products. W artykule przedstawiono pierwsze wyniki analizy uszkodzeń zmęczeniowych z zastosowaniem emisji akustycznej (AE) przeprowadzone na materiale stosowanym do budowy statków. AE umożliwia monitorowanie propagacji pęknięć w czasie wolnozmiennych prób zmęczeniowych w warunkach asymetrycznego trójpunktowego zginania. Oczekiwano, że warunki propagacji pęknięcia zmęczeniowego będą się zmieniać od sposobu I do sposobu mieszanego I/II, co byłoby bliższe rzeczywistym warunkom pracy. Wykonano również badania zmęczeniowe z wykorzystaniem cieczy w celu określenia i oceny różnicy w propagacji fal AE poprzez ciecz i materiał będący w kontakcie bezpośrednim z tą cieczą. Dane pomiarowe uzyskane podczas badań zmęczeniowych zawarte są w bazie danych, wykorzystywanej do analizy metodą pattern recognition do separacji sygnałów AE pochodzących z propagacji pęknięć zmęczeniowych i korozji od tła akustycznego.

EN

Corrosion damages and fatigue cracks are the main causes of structural failures in all surface transport products as ships, road tankers and railway tank cars. Both types of degradation, i.e. the degradation of material and structure, are the subject of investigations carried out within the framework of a collaborative project of the 7th Framework Programme (Transport) entitled Cost effective corrosion and fatigue monitoring for transport products. In this paper, the first fatigue tests using acoustic emission (AE) performed on ship building materials have been demonstrated. AE enables us to monitor the crack propagation during low fatigue tests performed on specimens under asymmetric three-point bending load. It was expected that fracture behaviour would move from Mode I to Mixed-Modes I/II, which would be closer to reality. For reference, tests were also made in liquid to obtain and evaluate the differences in AE waves propagation in liquid and in material directly contacting this liquid. The data obtained during fatigue tests are included in a database used in pattern recognition analysis to separate the signals due to fatigue crack propagation and corrosion damages from background noise.

18

Experimental study on fatigue damage of train K6 spring

Huang H., Ji S., Huang G., Qin X., Shui G.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

131--133

EN

Springs’ fatigue life and damage are key evaluation parameters for railway train bogies. Fatigue experiment on K6 bogie spring is carried out by digital display hydraulic pulse fatigue test device. Spring fatigue life is estimated by using nominal stress method. Based on the technology of ultrasound nondestructive test device, the relationship between accumulation of internal fatigue damage and cycle loading times is obtained. The results indicate that same batches of K6 springs have high reliability; spring material internal fatigue damage increases as cycle loading times.

PL

W artykule przedstawiono wyniki badań dotyczących zmęczenia sprężyn w podwoziach wagonowych. Analizie, przy pomocy hydraulicznego urządzenia testującego poddano sprężynę wagonową typu K6. Korzystając z badań ultradźwiękowych określono związek między tworzeniem się skupisk uszkodzeń wewnętrznych a cyklicznym obciążaniem.

19

Failure analysis (experimental and numerical approach) of gas turbine generator cooling fan in comparison between using 2types (14◦ and 19◦ angle of attack) of blades

Jahangiri A., Torshizi S. E. M., Nikravesh S. M. Y.

Engineering Transactions

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2013

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Vol. 61, iss. 2

99--117

EN

In gas turbine power plants, a fan is used as a cooling system to dissipate generated heat in coils (copper conductors) and generator electric circuits at the end sides of its rotor. In some cases, fracture of blades causes a short circuit between rotor and stator and consequently generator explosion and ﬁnancial problems. The fracture of cooling fan blades has occurred ﬁve times at the turbine side of the generator in our case of study, just 100hr after resuming operations after an overhaul. Using numerical analysis as well as laboratory investigation – including visual inspections, metallography and SEM – can help better ﬁnd failure problems that cause blade failures. A series of numerical analysis was performed to diagnose the possible cause of failure. CFD analysis is used to study the airﬂow distribution in order to observe probable separation phenomenon and pressure forces as they are imposed on fan blades due to operation. A ﬁnite element method was utilized to determine the stresses and dynamic characteristics of the fan blade (natural frequencies, stresses and vibrations).

20

Damage modeling in graded layer system

Petaś M., Mróz K., Doliński K.

Acta Mechanica et Automatica

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2013

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Vol. 7, no. 2

99--106

EN

The simplified approach to the modelling of low cycle fatigue (LCF) of functionally graded materials (FGM) based on the continuum mechanics is presented. The fatigue damage model takes into account the mechanical part of the load and a constant service temperature. The concept of FGM as a particle-reinforced metal-matrix composite with gradual change of the reinforcement fraction is used. The FGM is considered as a material consisting of homogeneous layers containing different volume fractions of the reinforcement. The variation of the reinforcement fraction changes the material properties for each layer. The different material properties are obtained according to modified rule of mixture. Since the fatigue damage of metal matrix composites is strongly influenced by the inelastic deformation of the metallic matrix, the constitutive equations of LCF damage model are taken into consideration. The combined isotropic/kinematic hardening model with linear behaviour of isotropic and kinematic parts of hardening is adopted. The damage scalar parameter is associated with the plastic energy dissipation which is used to update the material properties. The fatigue damage model presented in this paper is applied to the fatigue damage analysis of the cooling channel of thruster used in space shuttles and rockets.