Defects in Turbine Impeller Blades with Non-destructive Testing: Modeling, Ultrasonic Waves, Defect Analysis

Author(s):  
Esmaeil Mirmahdi
2021 ◽  
Author(s):  
◽  
Matthew Thomson

<p>This thesis focuses on the application of high frequency ultrasound as a tool for performing non-destructive testing for pultruded fibre reinforced composite (FRC) rods. These composite rods are popular in the manufacturing, construction and electrical industries due to their chemical, electrical and strength properties. Such FRCs are manufactured on automated production lines that operate day and night. Non-destructive testing techniques are desired to quickly and accurately detectmanufacturing flaws such as coating thickness irregularities and surface cracks. Layers and cracks can present as large changes in acoustic impedance and will strongly reflect ultrasonic waves. Combined with their low cost, east of use and absense of potentially harmful radiation, ultrasound has proven popular worldwide for Non-Destructive Testing. Finite Element Analysis (FEA) was employed to investigate the propagation of ultrasonic waves through layers of material to simulate a thickness measurement and the ability of ultrasound to measure thicknesses was proven. Experimental work was conducted on two fibre reinforced composite samples with varying thickness coatings of plastic and paint. The thickness was measured accurately using immersion transducers at 50MHz and a resolution of 20μm was attained through the use of matched filtering techniques. Surface acoustic waves, particularly Rayleigh waves were investigated using FEA techniques so that the generation, scattering and detection of such waves was understood. This lead to the development of methods for detecting surface cracks in glass using Rayleigh waves and these methods were successfully used in experimental work. Wave propagation in fibre reinforced composites was modelled and experimentally investigated with the results confirming theoretical expectations. Finally a Rayleigh wave was launched onto a fibre reinforced composite sample however the amount of energy leakage into the water was so great, due to the acoustic impedance of water, the detection of the wave was prevented. The conclusion reached was that an immersion setup was not appropriate for launching a travelling Rayleigh wave.</p>


1992 ◽  
pp. 500-504
Author(s):  
F. GUILLOIS ◽  
C. CORBEL ◽  
D. DAVID ◽  
H. TRETOUT ◽  
R. DE MOL ◽  
...  

2021 ◽  
pp. 31-36
Author(s):  
В.В. Ларионов ◽  
А.М. Лидер ◽  
Д.О. Долматов ◽  
Д.А. Седнев

Nowadays, automation is an actual issue in the development of methods and equipment for ultrasonic non-destructive testing. The conditions of modern industrial production require the development and application the automated testing equipment which is versatile to a wide range of manufactured products, which can have a complex shape. In this paper, we propose a technique for ultrasonic testing of complex-shaped objects. Such technique implies the application of six degrees of freedom robotic manipulators to ensure the required refraction angle of ultrasonic waves into the test object at each measuring position. The trajectory of the robot movement during scanning is provided by restoring the surface profile of the test object using optical profilometry and determining the location of the test object relative to the robotic manipulator using a probe tip. Within the framework of this work, the effectiveness of the developed technology is verified experimentally.


2014 ◽  
Vol 6 (5) ◽  
pp. 514-519 ◽  
Author(s):  
Tomas Šlivinskas

The article analyzes masonry as composite material and presents the factors that affect the mechanical characteristics of masonry. The article also deals with the most frequently used destructive and non-destructive testing methods for the compressive strength of masonry mortar as well as related advantages and disadvantages. Moreover, the analysis of methods for testing ultrasonic waves has been carried out. The article reveals that for using the methodology of testing a mortar bonded wafer, the compressive strength correlation of masonry mortar is set between the ascertainment of masonry mortar strength using a regular mortar testing methodology (LST EN 1015-11:2004) and the compressive strength of mortar possibly taken from masonry joints. The obtained results of an experimental study on the samples have demonstrated that the strength reduction ratio of masonry mortar depends on the compressive strength of mortar. The value of the ratio is increasing with the descending compressive strength of mortar. Šiame straipsnyje nagrinėjamas mūras kaip kompozitinė medžiaga. Apžvelgiami veiksniai, veikiantys mechanines mūro charakteristikas. Išnagrinėti dažniausiai taikomi mūro skiedinio gniuždomojo stiprio tyrimų metodai, pateikti metodų privalumai ir trūkumai. Straipsnyje, taikant klijuotų skiedinio plokštelių bandymo metodiką, nustatyta mūro skiedinio gniuždomojo stiprio priklausomybė tarp mūro skiedinio stiprio nustatymo pagal įprastinę skiedinio bandymo metodiką ir skiedinio, tikėtina, paimto iš mūro siūlės, gniuždomojo stiprio.


2011 ◽  
Vol 8 (4) ◽  
pp. 988-995
Author(s):  
Baghdad Science Journal

In this work the corrosion behavior of Al metal was studied by using non- destructive testing (NDT), which is a noninvasive technique for determining the integrity of a material. The ultrasonic waves was used to measure the corrosion which occur by two corrosive medium (0.1N sodium chloride and 0.1N sodium hydroxide) and study the corrosion by weight-loss method and electrochemical method in addition to performance the microscopic inspection for the samples before and after the immersion in the corrosive medium. Corrosion parameters were interpreted in these media which involve corrosion potential (Ecorr) and corrosion current density (icorr). The results indicate that both media was corrosive but the 0.1N NaOH was more corrosive than 0.1N NaCI. Micro hardness test indicates that, the hardness value of the testing metal is decrease in 0.1N NaOH solution more than 0.1N NaCl solution with longest time of immersion.


Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6148
Author(s):  
Hossam Selim ◽  
Rubén Picó ◽  
Jose Trull ◽  
Miguel Delgado Prieto ◽  
Crina Cojocaru

In this work, we numerically investigate the diffraction management of longitudinal elastic waves propagating in a two-dimensional metallic phononic crystal. We demonstrate that this structure acts as an “ultrasonic lens”, providing self-collimation or focusing effect at a certain distance from the crystal output. We implement this directional propagation in the design of a coupling device capable to control the directivity or focusing of ultrasonic waves propagation inside a target object. These effects are robust over a broad frequency band and are preserved in the propagation through a coupling gel between the “ultrasonic lens” and the solid target. These results may find interesting industrial and medical applications, where the localization of the ultrasonic waves may be required at certain positions embedded in the object under study. An application example for non-destructive testing with improved results, after using the ultrasonic lens, is discussed as a proof of concept for the novelty and applicability of our numerical simulation study.


2021 ◽  
Vol 45 (4) ◽  
pp. 329-334
Author(s):  
Irida Markja ◽  
Klodian Dhoska ◽  
Dervish Elezi ◽  
Reza Moezzi ◽  
Michal Petru

In this paper we have proposed an experimental study of the steel grains sizes effect on the shift frequency of the ultrasonic waves being propagated in steels. Ultrasonic testing has been used in most inspection services for different materials as non-destructive testing. The novelty of our research work has been focused on the investigation of the new method for determining microstructure evolution of metals by using ultrasonic signals in conjunction with changes in grain size and hardness of steels. Furthermore, we have studied the microstructure of steel types S355, S275, Corten B and S275N. The microstructure results of steels have shown the changes that have been undergone from thermal and mechanical processes by using the attenuation of ultrasound waves during non-destructive testing.


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