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1

Influence of the Cooling Rate on Damping Characteristics of the ZnAl4Cu1 Alloy

Piwowarski Grzegorz, Gracz Beata

Journal of Casting & Materials Engineering

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2022

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Vol. 6, no. 3

58--63

EN

The paper presents the results of damping coefficient tests in the ZnAl4Cu1 alloy (ZL5). The damping coefficient has been calculated on the basis of specimen measurements obtained with the use of the signal echo method. The method consists in passing the ultrasonic wave through the tested material. The ultrasonic wave from a transmitting and receiving head passes through a specimen, bounces off its bottom surface and comes back to the measuring head in the form of a signal echo. Difference in the signal strength between the first and the second echo in relation to the distance travelled by the ultrasound wave is a measure of the material’s damping characteristics. The specimens were cast into three molds made of different materials, i.e. green sand, plaster and metal. Thermophysical properties of these materials are different what affecting the rate of heat absorption from the cast. Three series of specimens have been obtained which cooled at different rates. The specimens were then subjected to ultrasound and microscopic tests to assess the alloy structure. The internal alloy structure affects its damping properties to a great extent.

2

Improvement of cutting tool performance during machining process by using different shim

Rogov V. A., Ghorbani S., Popikov A. N., Polushin N. I.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 3

694--710

EN

Modern metal processing is characterized by high spindle speed machines causing high frequency vibrations. This significantly increases the requirements for stiffness and damping of cutting tool. The purpose of this study is to improve the quality of machined surface and the efficiency of hard turning using shim with high damping properties in the clamp set of insert. Five shims made of ceramic, epoxy granite, sandstone, granite and chlorite schist are proposed. Computer simulation and experimental investigation are provided to analysis the state of stress–strain in clamp set construction of insert. Static and dynamic characteristics of cutting tool with shim made of different materials are studied. In addition, the relationship between vibro-acoustic signal and material of the shim, wear of cutting edge, surface roughness and cutting conditions during hard turning are analyzed. It is concluded that using shim made of epoxy granite and sandstone improved damping capacity of the cutting tool and surface roughness by reducing vibration during machining process.

3

Applications Of Mechanical Spectroscopy To Industrial Materials

Schaller A.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2A

1085--1089

EN

The paper is a review of original results, which were obtained by mechanical spectroscopy in the development of industrial materials, such as grey cast iron (damping capacity), aluminum alloys (recrystallization), nickel alloys (grain boundary embrittlement) and gold alloys (hardening mechanisms). Moreover it is shown that the study of grain boundary sliding at high temperature has led to the development of new grades of zirconia exhibiting a high toughness and a good resistance to creep. It is also recalled that mechanical spectroscopy has been a mandatory technique in the development of light metallic materials, which exhibit simultaneously good mechanical properties and a high damping capacity, and are consequently well suited to transport means.

PL

Artykuł prezentuje przegląd oryginalnych wyników, które zostały uzyskane za pomocą spektroskopii mechanicznej podczas rozwoju materiałów przemysłowych, takich jak żeliwo szare (zdolność tłumienia), stopów aluminium (rekrystalizacja), stopów niklu (kruchość granic ziaren), i stopów złota (mechanizmy umocnienia). Ponadto pokazano, że badania poślizgu granicy ziaren w wysokiej temperaturze umożliwiły rozwój nowych gatunków tlenku cyrkonu wykazujących wysoką wytrzymałość i dobrą odporność na pełzanie. Przypomniano także, że spektroskopia mechaniczna jest obowiązkową techniką stosowaną w rozwoju lekkich materiałów metalowych, które wykazują jednocześnie dobre właściwości mechaniczne oraz wysoką zdolność tłumienia, a tym samym są odpowiednie do zastosowania w środkach transportu.

4

Ultrasound Wave Attenuation of Grain Refined High – Zinc Aluminium Sand-cast Alloys

Krajewski W. K., Buraś J., Krajewski P. K., Piwowarski G.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 2

51--54

EN

The paper presents results of measuring attenuation coefficient of the Al-20 wt.% Zn alloy (AlZn20) inoculated with different grain refiners. During experiments the melted alloys were doped with Al-Ti3-C0.15 refining master alloy. Basing on measurements performed by Krautkramer USLT2000 device with 1MHz ultrasound wave frequency it was stated that grain refinement reduces the attenuation coefficient by about 20-25%. However, the examined alloys can be still classified as the high-damping ones of attenuation greater than 150 dB/m.

5

O tłumieniu drgań w materiałach kompozytowych

Pietrzak K., Klasik A., Makowska K., Sobczak J. J., Wojciechowski A., Rudnik D.

Prace Instytutu Odlewnictwa

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2012

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T. 52, z. 4

53-96

PL

Opracowanie dotyczy zdolności do tłumienia drgań kompozytów o osnowie stopu aluminium A359 zbrojonych 10%, 20% i 30% cząsteczek SiCp poddanych wielokrotnemu przetopowi. Celem badań było wykazanie, że recykling symulowany wielokrotnym przetopem nie zmienia istotnie charakterystyk tłumiących badanych materiałów. Na podstawie uzyskanych wyników można stwierdzić, że specyfika powierzchni międzyfazowej SiCp/ osnowa kompozytu stanowi główny czynnik wpływający na charakterystyki tłumiące kompozytów. Jednocześnie należy podkreślić, że właściwości powierzchni międzyfazowej SiCp/ osnowa kompozytu zależą od metody wytwarzania. Otrzymane wyniki potwierdzają potencjalne możliwości wprowadzenia do praktycznych rozwiązań przemysłowych recyklingu realizowanego prostą i ekonomicznie efektywną metodą wielokrotnego przetapiania. Należy jednak skupić wysiłki na minimalizacji porowatości gazowo-skurczowej podczas kolejnych procesów odlewania, aby nie dopuścić do pogorszenia charakterystyk mechanicznych.

EN

The study adresses the problem of the damping capacity of metal matrix composites based on A359 alloy reinforced with 10%, 20% and 30% SiCp, subjected to multiple remelting. The aim of the research was to prove that the recycling process simulated by multiple remelting does not significantly change the damping characteristics of the investigated materials. Based on the results obtained it was possible to ascertain that the specific character of the SiCp/ metal matrix interface is the main feature affecting the damping capacity of these materials. At the same time, it should be stressed that the properties of the SiCp/ metal matrix interface depend greatly on the manufacturing method. Strong bond produced between the reinforcing phase and composite matrix guarantees optimum mechanical characteristics at the expense of reduced damping capacity. The results confirm the potential possibilities of introducing to industrial practice the solution offered by the recycling process, which is a simple and economically effective method carried out by multiple remelting. However, efforts should focus on minimization of gas-shrinkage porosity during the successive casting operations to avoid the deterioration of mechanical characteristics.

6

Vibration Analysis of Electrorheological Fluid Filled Cylindrical Shell for Harmonic Drive

Tylikowski A.

Machine Dynamics Problems

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2004

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Vol. 28, No. 2

107-117

EN

This study presents vibration analysis of a closed cylindrical shell and annular plate partially filled with the controllable fluids. The shell is connected with an annular plate clamped at the inner edge. The transverse plate displacement is taken in to account. The analysis will use the Kirchhoff-Love theory to describe the thin shell motion. The viscous model of external damping with the constant coefficient is assumed to describe the dissipation of the shell energy. Inside the main flexpline the closed cylindrical shell is axisymmetrically mounted, in such a way that the space between the shells is filled by the controllable fluid and the both annular ends are sealed. The analysed structure as a part of harmonic drive can generate vibration due to the wave generator operation. Assuming a harmonic single frequency excitation at the end x = 0 steady-state responses of dynamics equations are sought as harmonics with the same angular velocity. The fluid-filled laminated cylindrical shell and annular plate has shown an increased and controllable damping capacity as compared to the conventional shell.

7

Meaning of the carbide banding in the vibration damping phenomenon.

Pietrzak K., Wojciechowski A.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

1183-1186

EN

The presented research work contains the results of investigations concerning the stereological aspects of damping capacity in tool steel. The Forster's elastomat was used to determine the damping characteristics. Basing on the quantitative metallographic method, the effect of carbide banding on vibration damping capacity of steel submitted to the forging process has been determined. As the result, the regression between the logarithmic decrement of vibrations and estimator of surface area carbide-matrix has been obtained. The carbide size limit above which the carbide particles affect significantly the vibration damping phenomenon has been determined too.