Evaluation of the acoustic emission caused by the chip segmentation frequency during machining of titanium alloy

2020 ◽  
Vol 87 (11) ◽  
pp. 714-720
Author(s):  
Daniel Schwär ◽  
Germán González ◽  
Eric Segebade ◽  
Frederik Zanger ◽  
Michael Heizmann
Keyword(s):  
Acoustic Emission ◽  
Titanium Alloy ◽  
Spectral Analysis ◽  
Chip Formation ◽  
Acoustic Emissions ◽  
Turning Process ◽  
Longitudinal Turning ◽  
The Relationship ◽  
Chip Analysis

AbstractThis work investigates the relationship between acoustic emission and chip segmentation frequency of Ti-6Al-4V at the external longitudinal turning process. Therefore, several sensors like structure borne sensors, microphones and a force dynamometer have been installed in a vertical turning machine. To induce a change of the segmentation frequency, several experiments with different feed rates have been carried out. From each experiment the acoustic emissions have been recorded and the generated chips have been analyzed. Since the chips get stretched or compressed during the chip formation the change in the length is calculated to get an estimation of the segmentation frequency. The comparison of the spectral analysis of the acoustic emission signals and the chip analysis has shown that both methods show the same tendency. The segmentation frequency decreases with increasing feed.

scholarly journals ACOUSTIC EMISSION AND DAMAGE CHARACTERISTICS OF ANTHRACITE UNDER DIFFERENT CONDITIONS

2021 ◽  
Vol 55 (2) ◽  
pp. 213-218
Author(s):  
Jiyu Zheng ◽  
Xiaohua Jin ◽  
Kunyun Tian ◽  
Yinbo Zhou
Keyword(s):  
Acoustic Emission ◽  
Coal Sample ◽  
Characteristic Curve ◽  
Great Influence ◽  
Acoustic Emissions ◽  
Slow Increase ◽  
Loading Rates ◽  
The Relationship ◽  
Damage Characteristic ◽  
Peak Count

Acoustic emission (AE) can be used to observe the process of coal fracture propagation. Based on a press and acoustic-emission platform, the damage and acoustic-emission characteristics of anthracite with different loading rates, water amounts and sizes were studied. The results show that there is less acoustic emission in the initial compression stage of coal; acoustic emission is more active in the transition from elastic deformation to plastic deformation, which is manifested in the following aspects: the faster the loading rate, the higher is the number of acoustic-emission events; the peak count of acoustic emissions of a saturated-coal sample is significantly lower than that of a natural-coal sample. Coal samples and large coal samples emit even more sounds. Based on the normalization of acoustic-emission counts, the relationship between damage variables and stress-strain is studied, and it is characterized by an initial slow increase, followed by a rapid increase; however, different factors have a great influence on the damage-characteristic curve. The research results have a certain guiding significance for the coal and rock disaster prediction.

Surface roughness of the Ti-6Al-4V ELI titanium alloy after the turning process

2019 ◽  
Vol 2 (98) ◽  
pp. 74-80
Author(s):  
R. Rosik ◽  
N. Kępczak ◽  
M. Sikora ◽  
B. Witkowski ◽  
R. Wójcik ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Surface Roughness ◽  
Titanium Alloy ◽  
Multiple Regression ◽  
Roughness Parameter ◽  
Regression Function ◽  
Turning Process ◽  
Longitudinal Turning ◽  
Machining Parameter ◽  
The Mathematical Model

Purpose: The purpose of this article is discussing the methods of determining the surface roughness of the Ti-6Al-4V ELI titanium alloy obtained after longitudinal turning. The method of determining the mathematical model used for determining the Rz roughness parameter and then the results obtained were compared with values measured and calculated on the basis of equations available in the literature. Design/methodology/approach: The mathematical model in the form of multiple regression function of exponential polynomial was determined using the algorithm of the acceptance and rejection method. The data for calculations was obtained by measuring the surface roughness after turning with different machining parameter values. Findings: A mathematical model was elaborated in the form of a multiple regression function, enabling calculation of the Rz parameter describing the Ti-6Al-4V ELI titanium alloy surface roughness after longitudinal turning. The verification of the dependence obtained confirmed its accuracy. Research limitations/implications: Further research should encompass other values of machining plate geometry, as well as other types of cooling and lubricating fluids and method of applying them. Practical implications: The mathematical model can be helpful when choosing the conditions in which the turning process will be carried out. It also constitutes a basis for further optimisation of that process. Originality/value: The results of this research are a novelty on a worldwide scale. No research of this type has been conducted with regard to analyses and optimisation of longitudinal turning of the Ti-6Al-4V ELI titanium alloy.

scholarly journals Analysis of mathematical models for turning the titanium alloy WT3-1

Mechanik ◽  
2017 ◽  
Vol 90 (10) ◽  
pp. 858-860
Author(s):  
Józef Zawora ◽  
Rafał Świercz ◽  
Mieczysław Marciniak ◽  
Lucjan Dąbrowski
Keyword(s):  
Titanium Alloy ◽  
Regression Analysis ◽  
Experimental Design ◽  
Mathematical Models ◽  
Stepwise Regression ◽  
Stepwise Regression Analysis ◽  
Polynomial Form ◽  
Turning Process ◽  
Multiple Stepwise Regression Analysis ◽  
Longitudinal Turning

Mathematical models for longitudinal turning process of the titanium alloy WT3-1 were presented in this paper, both in the exponential and the polynomial form. The experimental design and the multiple stepwise regression analysis were used to develop the mathematical models.

scholarly journals The temperature- and density-dependent acoustic emission response of snow in monoaxial compression tests

2004 ◽  
Vol 38 ◽  
pp. 291-298 ◽  
Author(s):  
Carlo Scapozza ◽  
Felix Bucher ◽  
Peter Amann ◽  
Walter J. Ammann ◽  
Perry Bartelt
Keyword(s):  
Acoustic Emission ◽  
Relaxation Times ◽  
Acoustic Emissions ◽  
Wide Band ◽  
Strain Rates ◽  
Compression Tests ◽  
Load History ◽  
Fine Grained ◽  
Rate Controlled ◽  
The Relationship

AbstractResults of acoustic emission tests on cylindrical specimens under compression are reported. Deformation-rate-controlled tests with strain rates ranging from 1.1 × 10-6 s-1 to 2.6 × 10-3 s-1 at temperatures between T = -11.2°Cand T = -1.7°C were performed. The investigated snow was fine-grained, with a density varying between 220 and 380 kgm-3. The acoustic emission was measured with two distinct piezoelectric sensors: a wide-band sensor (frequency 100–1000 kHz) and a resonant sensor (frequency 35–100 kHz). The relationship between the applied strain rate and the measured maximum acoustic-emission rate as a function of temperature and density was found to obey a power law, which is valid for the ductile behaviour range. The quantitative and qualitative effects produced on the acoustic emissions during the transition from ductile to brittle behaviour, occurring at strain rates of approximately 1 × 10-3 s-1, are reported. Finally, the influence of the load history on the acoustic emissions of snow is discussed on the basis of a cyclic test, including deformation-controlled loading steps and relaxation steps, performed at different strain rates and different relaxation times.

scholarly journals Acoustic Emission Waveform Changes for Varying Seeded Defect Sizes

2006 ◽  
Vol 13-14 ◽  
pp. 427-432 ◽  
Author(s):  
S. Al-Dossary ◽  
R.I. Raja Hamzah ◽  
D. Mba
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emissions ◽  
Defect Size ◽  
Geometric Size ◽  
The Relationship ◽  
Geometric Defect

The investigation reported in this paper was centered on the application of the Acoustic Emissions (AE) technology for characterising the defect sizes on a radially loaded bearing. The aim of this investigation was to ascertain the relationship between the duration of AE transient bursts associated with seeded defects to the actual geometric size of the defect. It is concluded that the geometric defect size can be determined from the AE waveform.

The influence of ultrasound signal parameters on sonoluminescence light intensity

2013 ◽  
Vol 62 (4) ◽  
pp. 605-612
Author(s):  
Marek Szmechta ◽  
Tomasz Boczar ◽  
Dariusz Zmarzły
Keyword(s):  
Acoustic Emission ◽  
Acoustic Waves ◽  
Power Transformer ◽  
Electrical Power ◽  
Partial Discharges ◽  
Research Project ◽  
Insulation Systems ◽  
Secondary Phenomenon ◽  
New Research ◽  
The Relationship

Abstract Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of Electrical Power Engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn’t prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical power devices based on non-invasive acoustic emission method.

scholarly journals Towards Dry Machining of Titanium-Based Alloys: A New Approach Using an Oxygen-Free Environment

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1161
Author(s):  
Hans Jürgen Maier ◽  
Sebastian Herbst ◽  
Berend Denkena ◽  
Marc-André Dittrich ◽  
Florian Schaper ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Wear Mechanism ◽  
Chip Formation ◽  
Cutting Forces ◽  
High Vacuum ◽  
Argon Atmosphere ◽  
Dry Machining ◽  
New Approach ◽  
Underlying Mechanisms ◽  
Free Environment

In the current study, the potential of dry machining of the titanium alloy Ti-6Al-4V with uncoated tungsten carbide solid endmills was explored. It is demonstrated that tribo-oxidation is the dominant wear mechanism, which can be suppressed by milling in an extreme high vacuum adequate (XHV) environment. The latter was realized by using a silane-doped argon atmosphere. In the XHV environment, titanium adhesion on the tool was substantially less pronounced as compared to reference machining experiments conducted in air. This goes hand in hand with lower cutting forces in the XHV environment and corresponding changes in chip formation. The underlying mechanisms and the ramifications with respect to application of this approach to dry machining of other metals are discussed.

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