bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cutting parameters influence analysis on fatigue behaviour of dry turned UNS A97075 alloy after corrosion
Authors: Martín-Béjar S , Trujillo F J , Bermudo C , Herrera M , Sevilla L 
Published: February 2021

AbstractAluminum alloys, particularly series 2000 (Al-Cu) and 7000 (Al-Zn), are widely used for structural elements in aircraft. Machining processes are frequently applied in manufacturing these parts. The actual trend in the machining of these components is to reduce or eliminate the use of lubricants, due to environmental reasons. Among the different techniques, dry machining is commonly used for aluminum alloys. However, dry machining generates higher severe cutting conditions, which may negatively affect the surface integrity and the mechanical properties of the machined parts. In this regard, fatigue life is one of the most important mechanical properties to take into account. Micro-cracks generation and nucleation strongly depend on the surface conditions of the machined parts. Additionally, the addition of Zn to pure aluminum (7000 series) reduces the corrosion resistance. Despite its importance, there is a lack of research devoted to analyze the cutting parameters influence on fatigue behaviour, before and after corrosion, in dry machining of these alloys. Therefore, in this work, the cutting speed and feed rate influence on fatigue behaviour of the UNS A97075 (Al-Zn) alloy has been analyzed. Several rotating bar bending fatigue tests have been carried out, studying and comparing the fatigue life curves obtained as a function of the cutting parameters, before and after an immersion corrosion process. The experimental results have revealed that an increment in the cutting speed and feed rate gives rise to fatigue life reduction.
A case study on 3D scanning, digital reparation and rapid metal additive manufacturing of a centrifugal impeller
Authors: Kladovasilakis N , Kontodina T , Charalampous P , Kostavelis I , Tzetzis D , Tzovaras D 
Published: February 2021

Abstract
This paper demonstrates a comprehensive method for digital restoration and rapid manufacturing of a fully functional mechanical component. A damaged centrifugal impeller of an automotive engine was reverse-engineered via a 3D laser scanner, with which the 3D model of the investigated object was digitally captured. Utilizing advanced design software and surface modelling, the missing fragments were restored and the impeller’s 3D digital model was reconstructed. Metal additive manufacturing technology and more specifically the Selective Laser Melting (SLM) technique was employed to construct a functional metal impeller. Stainless steel 17-4 PH powder was used as the printed material. To ensure the exploited powder was appropriate for the part to be manufactured, we applied characterization of the feedstock material was conducted through two different characterization methods, i.e. granulometry and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX). Furthermore, Surface Distance Maps (SDM) were calculated to correlate the geometrical deviations between the physical 3D printed part and the digital model in order to examine the accuracy of the applied method.
Improving of preventive management for flat rolling products quality indices
Authors: Kukhar V V , Kurpe O H , Prysiazhnyi A H , Khliestova O A , Burko V A , Balalayeva E Yu , Yelistratova N Yu 
Published: February 2021

Abstract
Based on the combination of ISO and Lean system tools, the methodology of continuous optimization of technology and quality improvement of rolled steel has been improved. To assess the condition and determine the production level to set limits to process indices the use of colored markers was suggested. The improved flat rolling quality control methodology is based on the use of Deming cycle and includes the use of such analysis tools as Fishbone (Ishikawa) diagram, Pareto principle, distribution diagrams, 3σ rules and Shewhart control charts. For the first time, differentiated corrective solutions for plate steel which is produced with different levels of process stability and quality indices are suggested. The inspection was carried out with the data from the mechanical properties of flat steel products 14 mm thick from K60 steel, produced by thermo-mechanical controlled process on a plate mill 3600. Introduction of the methodology allowed to reduce the standard deviation of yield strength, tensile strength and percentage elongation after fracture of the studied rolled products by 44%, 31% and 46%, respectively, indicating an overall increase in technology stability and quality indices and implementation of an effective tool for their preventive control.
Validating dynamic crush response of unidirectional carbon fibre tube via finite element analysis method using LS-DYNA
Authors: Samuel R , Asadi M , Tarda A , Simbotin G , Markopoulos A P 
Published: February 2021

Abstract
Crashworthiness of composite structures is of significant interest to manufacturers and operators as composites become more commonly used in automobiles and aircraft. Experimental crush testing remains an important tool in the design of subfloor fuselage structures for crashworthiness, as numerical simulations are still largely unable to accurately predict the crushing response of complex composite structures. In this paper, dynamic crush testing of carbon-fibre/epoxy specimens experimental result is validated using the modelling and simulation software LS-DYNA to understand impact behaviours under dynamic loading for finite element simulations. The tubular finite element model was modelled using MAT54 and was impacted by a 65KG rigid wall impactor with an impact velocity of 55 km/h. Material card parameters were evaluated to understand crush behaviour of the FE model. Upon analysis the experimental results and the FEA results showed a good correlation. Modelling criteria used for this model can be further used to simulate crush response of unidirectional carbon tubes under dynamic impact.
Prediction of roughness of planar surfaces processed with toroidal milling through an artificial neural network
Authors: Osan A R , Banica M , Nasui V 
Published: February 2021

Abstract
This paper is intended to create an artificial neural network capable of generating new values for the roughness on the basis of experimentally obtained data bases. Experimentally you will measure the roughness of the flat surfaces processed with the toroidal milling, the process factors being the input neurons of the neural network, following the roughness values being the output neurons. It aims to modify the input neurons from the same neural network and generate new roughness values.
Investigation of the suitability of fiber reinforced polymer matrix composites for facilities operating in marine environment
Authors: Spasova D , Argirov Y , Mechkarova T , Atanasov N 
Published: February 2021

Abstract
This paper is related to the production and investigation of the structure, the mechanical and physicochemical properties of two kinds of fibre reinforced polymer matrix composites in order to assess their suitability as materials used in equipment operating in marine environment. The one of the investigated composites has a polyester resin matrix and a reinforcement phase of six-layer fibreglass, and the other one has a vinylester resin matrix and a reinforcement phase which is a combination of three-layer fibreglass and three-layer biaxial fibreglass. A comparative analysis has been made of the relative weight, tensile strength and bending strength of the two types of composite materials.
Chemical and structural analyze of experimental biodegradable ZnMgY alloy
Authors: Panaghie C , Cimpoesu R , Alexandru A , Bernevig M , Manole V , Roman A M , Prisacariu B A , Paraschiv P , Cimpoesu N 
Published: February 2021

Abstract
Beside biocompatible classic metallic materials, biodegradable metals (BMs) like alloys of zinc (Zn-based) present a high potential as an alternative solution for permanent implants elements generally being applied for fractures restorations or other similar medical conditions. An experimental alloy, ZnMgY, was obtained using an induction furnace from high purity materials (Zn: 99,995 and master alloy MgY: 65-35 wt%), in Argon atmosphere. Microstructure of the alloy (after mechanical grinding and polish plus chemical etching) and chemical insights (before chemical etching) were taken using optical microscope (Zeiss+Motic digital camera for image acquisition) scanning electron microscope (SEM VegaTescan LMH II, SE, 30 kV, 16 mm WD) and dispersive energy spectroscopy (EDS Bruker, PB ZAF, Automatic mode of analyze, Point and Mapping features). The experimental alloy was five times re-melted in the induction furnace using a ceramic crucible. The experimental alloys present a good chemical homogenization without porosity, metallic inclusions or segregation.
Study of the durability of ferritic - austenitic steel samples after cyclical fatigue impact
Authors: Georgiev Georgi , Argirov Yaroslav , Mechkarova Tatyana , Spasova Daniela , Stoyanova Aneliya 
Published: February 2021

Abstract
The purpose of this article is to investigate the fatigue strength of corrosion resistant ferritic austenitic steels used in marine equipment. Two groups of sheet steel samples were prepared: the first group were reference parts and the second group of samples were welded. The fatigue tests were performed with specially developed vibrating equipment. The destroyed surfaces were examined by optical microscopy, and the phase composition by X-ray diffraction analysis. Fatigue strength was evaluated by the number of cycles needed for a crack at a certain alternating load. Fatigue tests show how multi-cyclical fatigue affects the formation and development of a fatigue crack, and metallographic and X-ray diffraction analysis shows the phase changes occurring in the structure of SAF 2507 steel.
Characterization of metallic materials used in food packaging
Authors: Necsulescu D A , Ciurdas M , Milea C 
Published: February 2021

Abstract
The work represents a comparative study of three type of metallic food package used in Romanian food industry. In this paper, three food packages made of low-alloy steel were analyzed. To characterize their properties, spectrometric analyzes were performed to determine the chemical composition, microhardness analyzes, optical microscopy and Fourier Transform Infrared Spectroscopy. The investigations on the three samples were achieved through X-ray Fluorescence Spectrometry (XRF) analysis performed with a Spectro XEPOS analyzer, optical microscopy analyzes performed on a Reichert UnivaR optical microscope, and microhardness tests by the Vickers method using the CV - 400 DTS tester / 2 (CV Instruments) and Fourier Transform Infrared Spectroscopy (FTIR) with JASCO 6200 analyzer, equipped with Golden Gate type attenuated total reflection (ATR) device. Following the investigations, the presence of epoxyphenolic resin was confirmed in the case of the first two samples and a layer of polyester in the case of sample three. Finally, conclusions are presented about the qualities of the selected packaging and their properties to keep safe the packaged products for a period of several months to several years.
The potential of wave energy in the coastal region of Romania
Authors: Rus M , Mereuta E , Novetschi M 
Published: February 2021

Abstract
In this study, the wave energy potential in the coastal region of Romania was analyzed. For this purpose, a reanalysis data set downloaded from ECMWF (European Centre for Medium-Range Weather Forecasts) was used. The reanalysis data contains information for various models. In this analysis the significant height of combined wind waves and swell, the mean wave direction and the mean wave period were analyzed in order to determine the potential of extracting clean energy from waves. The aim of this research is to analyze some performances factors (capacity factor, rated capacity, operating capacity, annul electricity production) of some of the most used wave energy convertors.
Modelling and practical application of autocorrelation functions of vibroacoustic oscillations in a machine dynamic system
Authors: Ignatyev A A , Samoylova E M , Zakharchenko M Yu , Ignatyev S A , Dobryakov V A , Vinogradov M V , Nasad T G , Karakozova V A 
Published: February 2021

Abstract
The paper considers applying the residue theory in obtaining mathematical models for autocorrelation functions of vibroacoustic oscillations in a machine dynamic system during the cutting process. It shows that these models are analogous to experimental data and reflects their practical application for assessing the dynamic quality of machine tools and setting a processing mode. Calculating the dynamic system stability margin is carried out automatically according to the oscillation index obtained from a real amplitude-frequency characteristic of the dynamic system. This characteristic, in its turn, is determined from the identified transfer function. The article considers the construction of a theoretical model for the autocorrelation function of vibroacoustic oscillations of a grinding machine dynamic system, that would be equivalent to the autocorrelation function obtained from experimental data. Such a model would be feasible to use to calculate the dynamic system transfer function of the machine with a subsequent evaluation of its stability margin. It substantiates applying the dynamic system stability margin of the machine as an informative characteristic based on measuring vibroacoustic oscillations during the cutting process to evaluate the technological system quality and stating an appropriate processing mode to achieve the required part surface quality. It is shown that the identification of transfer function under the established conditions by the autocorrelation function of vibroacoustic oscillations during cutting enables us, based on the maximum stability margin of the dynamic system, to determine the machine with the highest dynamic quality and set the cutting mode, which ensures high processing quality and reduces tool wear.
The algorithm of processing and presenting the digital trajectory data obtained when launching rocket vehicles
Authors: Spitsyn S V , Potapov V I , Koryachko V P 
Published: February 2021

Abstract
This research aims at finding a generalized algorithm suitable for processing and presenting the trajectory digital parameters of consumer onboard navigation equipment which is used in the process of space rocket launches. Processing and analysis of digital telemetric information coming from the onboard equipment during the flight and containing digital frames of trajectory measurements is one of the priority tasks as it is the analysis of the path deviations of the rocket that makes a significant contribution to a complete and informative assessment of the launch results. It is suggested that the generalized processing and presenting algorithm which contains the initial stages of the primary processing (extraction of digital frame structures, extraction of trajectory parameters from the frames, mathematical transformations of extracted parameters)as well as determination of primary and secondary values are necessary for solving the trajectory task and, eventually, forming a unified digital stream for representing trajectory measurements, for obtaining results of processing in graphical representation software.
Combining methods for end-to-end calculation of gas flow in a Laval nozzle
Authors: Dushkov R E , Dzerzhinsky R I 
Published: February 2021

Abstract
The paper solves the problem of selecting optimal methods and combining them when performing a complex calculation of all sections of the Laval nozzle. The problem is significant, since different flow modes are realized in different areas of the nozzle and it is impossible to use a single method for the full calculation. Solving the direct problem, parameters in the flow of gas are determined. Solving the reverse problem determine the profile of the Laval nozzle. Profiling is an important applied task for calculating the nozzles of rocket and aircraft engines, or designing experimental turbines. In this paper, we consider a two-dimensional plane axisymmetric flow of an inviscid perfect gas (on the example of dry air). The problem is solved starting with an accelerating subsonic flow via using methods of establishing and finite elements. For subsonic flow found an exact solution (Prandtl-Mayer flow). Solving the problem in a supersonic flow via using proximate methods (the method of characteristics and interpolation for the grid normalization). The solution is supplemented by a method that allows taking into account the features of axisymmetric flow in the nozzle to expand the applicability of the solution for real nozzles. The results obtained – the gas velocity field and the coordinates of nodes. Results allows estimation of the optimal size of the Laval nozzle for the given conditions, its shape, and obtain a flow profile depending on its initial characteristics defined in the previous section of the nozzle. The results of flow simulation can be applied to calculate the flow in circular sections, which are the most common in the current application. The results are confirmed by the solution using the finite element method, and the convergence of the solution in the diffuser is described in the current work. Theoretically, the solution can be applied to a mixture of gases, if peculiarities of physical and chemical transformations and the participation of combustion products are taken into consideration. In this case instead of parameters in the pre-chamber, the parameters of the combustion chamber and the products in it should be used as initial conditions. This calculation will be carried out in future studies of the authors.
Simulation of the thermal state of the blank surface layer at thermal-friction turn-milling
Authors: Sherov K , Tussupova S , Sikhimbayev M , Mussayev M , Ainabekova S , Imanbayev Ye , Karsakova N , Abisheva N 
Published: February 2021

Abstract
As a result of research, it was revealed that there is a problem of turning accurate large-sized, long parts, which is associated with an increase in productivity and quality of processing, as well as with a decrease in the cost of turning operations. To solve this problem, the authors developed a method of thermo-friction turn-milling and tool design. However, the lack of knowledge of the thermal phenomena occurring in the contact layer “blank-tool” during processing inhibits the widespread use of the proposed method. In this regard, this article simulated the thermal state of the surface layer during cutting. The results of modeling the thermal state of the surface layer when processing parts from difficult materials with thermofriction turn-milling are presented. The influence of cutting conditions and geometric parameters of the tool on the distribution of the temperature field of the surface layer of the workpiece during thermo-friction turn-milling is considered.
On the features of Hurst Exponent estimates of the Fractional Brownian motion calculated by the R/S-analysis
Authors: Ponomareva O , Porshnev S , Solomakha E 
Published: February 2021

Abstract
The article presents the analysis results of the dependence of the accuracy in estimating Hurst exponent of the Fractional Brownian motion by the R/S-analysis towards the method parameters Lmin
, Lmax
. It is found that the estimation of the Hurst exponent coinciding with its corresponding value is used to generate Fractional Brownian H〈mod〉 motion only when

L

max

=

L

max

〈
t
r
u
e
〉

. Otherwise, Hurst Exponent Estimate H depending on the value Lmax
varies in the span [0.25; 1.12]. The result obtained points out that it is necessary to critically revise the results of a number of studies where in order to analyze and forecast the dynamics of complex systems of different nature (for example, in economic ones) the authors employed the R/S-evaluation exponents of the Hurst exponent H of the time series (TS), composed of the exponents characterizing the state of the given system at a certain point.
Analysis, synthesis and modelling of air individual smart rescue system
Authors: Rakov D 
Published: February 2021

Abstract
The morphological approach is a successful analytical tool for development schematic, conceptual and preliminary design of new engineering systems in Aerospace. This investigation used a morphological approach to engineering solutions development as well as to tools for creating promising individual smart rescue system on conceptual design stage. The problem was solved in two stages. At a higher level of the hierarchy, the principle of action in morphological box was chosen. In the second phase, specific engineering solutions were explored. Analysis of engineering systems, solutions and solving technique and systems and their potential opportunities with technique provide correct guidelines to supply the reasonable decisions. Flight simulations, depending on different initial conditions, were performed using the LANE program.
Enhancing the efficiency of rebar use in reinforced concrete products’ manufacturing
Authors: Sherov K , Serova R , Yessirkepova A , Mussayev M , Zhanakov K , Smailova B , Turusbekova A , Mazhitova L 
Published: February 2021

Abstract
The article analyzes the state of rebar use in the conditions of construction enterprises of the Republic of Kazakhstan (RK). As a result of the research, it was found that today the domestic industry of construction materials is able to satisfy just a part of the needs of the Republic of Kazakhstan’s construction complex, and as a result, a significant share of the market is occupied by imported products, preventing a shortage of virtually all types of construction materials. The current situation has a negative impact on the prime cost of construction products’ manufacturing. It was also established that there is a high consumption of rebar for wastes, which exceeds the standards defined by State Standard and is about 2%. The consumption of rebar in this ratio also leads to an increase in the prime cost of reinforced concrete products’ manufacturing. For the effective use of reinforcing bars, which are the main components in reinforced concrete products’ manufacturing, it is proposed to separately use wastes of reinforcing bars, rods and wires to manufacture certain types of reinforced concrete products.
Reliability indexes of vibrating platforms for compaction of construction mixtures
Authors: Rogovskii I L , Delembovskyi M M , Voinash S A , Scherbakov A P , Teterina I A , Sokolova V A 
Published: February 2021

Abstract
In the article of experimental research and a particularly important prerequisite is to establish the required values with the least error, because the reliability of the information obtained from the processing of experiments is key to determine the true value of a parameter. According to the results of the study, data were obtained on the actual operating time for failure of the elements of the vibrating platforms VB-10V. The research identified the main prefabricated units and parts that failed: motor, gearbox, synchronizer, vibrator, propeller shafts, clutches. At the same time, cardan shafts and couplings failed the most. In some cases, the destruction of bearings in vibrating exciters has been demonstrated. The method of determining the number of experiments and estimating the error in measuring the studied parameters is based on the basic provisions of probability theory and mathematical statistics. The results of the research indicate a low level of reliability of the cardan shaft, which leads to a long downtime at an unscheduled time of repair, which is 0.8-1.2 hours in the presence of spare parts in stock. As a result of processing the statistical information of the cardan shaft reliability indicators, it was found that the average resource is 261.95 hours, the standard deviation is 53.2 hours, the coefficient of variation is 0.27.