Abstract The most common method of post-weld finishing is grinding with an abrasive tool. This finishing method leads to the occurrence of faults on the treated surface: locations missed or hardened twice, structural notches and stretching residual stress in the surface layer. The faults mentioned lead to the creation and development of ordinary as well as fatigue cracks, seizing or other damage. In addition, grinding is a process that often involves manual labour, which significantly increases the time required for finishing the procedure. Moreover, it is impossible to automate this process. Also, grinding is a process that is damaging for both people and the environment. In contrast to grinding and other processes of post-weld surface finishing, the innovative method, which is the subject of this article, does not have the faults and inconveniences of the previously mentioned techniques. The post-weld surface finishing method by moving of the innovative multi-edge cutting tool along the weld bead is presented in this article. In this method, machining allowance is treated as the weld bead height, which is flush-removed with the base material in one step during one pass of the cutting tool. The adjacent teeth height of changing and increasing according to the direction of feed and the difference in height between the first and last teeth are equal to the weld bead height. The number of cutting teeth necessary to flush-finish the weld bead with the base metal surface depends on the difference in the first and last teeth height and how it is divided. The tooth length is greater than half of the distance between the adjacent cutting teeth, which enables finishing the heterogeneous post-weld surface with many defects and increased hardness. The innovative method is characterised by short machining time of the weld bead and provides an accurate, efficient and economical process.
{"title":"The Innovative Post-Weld Finishing Method and Non-Standard Cutting Tool for Carrying Out this Method","authors":"Olha Dvirna","doi":"10.2478/ama-2024-0003","DOIUrl":"https://doi.org/10.2478/ama-2024-0003","url":null,"abstract":"Abstract The most common method of post-weld finishing is grinding with an abrasive tool. This finishing method leads to the occurrence of faults on the treated surface: locations missed or hardened twice, structural notches and stretching residual stress in the surface layer. The faults mentioned lead to the creation and development of ordinary as well as fatigue cracks, seizing or other damage. In addition, grinding is a process that often involves manual labour, which significantly increases the time required for finishing the procedure. Moreover, it is impossible to automate this process. Also, grinding is a process that is damaging for both people and the environment. In contrast to grinding and other processes of post-weld surface finishing, the innovative method, which is the subject of this article, does not have the faults and inconveniences of the previously mentioned techniques. The post-weld surface finishing method by moving of the innovative multi-edge cutting tool along the weld bead is presented in this article. In this method, machining allowance is treated as the weld bead height, which is flush-removed with the base material in one step during one pass of the cutting tool. The adjacent teeth height of changing and increasing according to the direction of feed and the difference in height between the first and last teeth are equal to the weld bead height. The number of cutting teeth necessary to flush-finish the weld bead with the base metal surface depends on the difference in the first and last teeth height and how it is divided. The tooth length is greater than half of the distance between the adjacent cutting teeth, which enables finishing the heterogeneous post-weld surface with many defects and increased hardness. The innovative method is characterised by short machining time of the weld bead and provides an accurate, efficient and economical process.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139138152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leszek Cedro, Krzysztof Wieczorkowski, A. Szcześniak
Abstract In adaptive model-based control systems, determining the appropriate controller gain is a complex and time-consuming task due to noise and external disturbances. Changes in the controller parameters were assumed to be dependent on the quadcopter mass, which was the process variable. A nonlinear model of the plant was used to identify the mass, employing the weighted recursive least squares (WRLS) method for online identification. The identification and control processes involved filtration using differential filters, which provided appropriate derivatives of signals. Proportional integral derivative (PID) controller tuning was performed using the Gauss–Newton optimisation procedure on the plant. Differential filters played a crucial role in all the developed control systems by significantly reducing measurement noise. The results showed that the performance of classical PID controllers can be improved by using differential filters and gain scheduling. The control and identification algorithms were implemented in an National Instruments (NI) myRIO-1900 controller. The nonlinear model of the plant was built based on Newton’s equations.
{"title":"An Adaptive PID Control System for the Attitude and Altitude Control of a Quadcopter","authors":"Leszek Cedro, Krzysztof Wieczorkowski, A. Szcześniak","doi":"10.2478/ama-2024-0004","DOIUrl":"https://doi.org/10.2478/ama-2024-0004","url":null,"abstract":"Abstract In adaptive model-based control systems, determining the appropriate controller gain is a complex and time-consuming task due to noise and external disturbances. Changes in the controller parameters were assumed to be dependent on the quadcopter mass, which was the process variable. A nonlinear model of the plant was used to identify the mass, employing the weighted recursive least squares (WRLS) method for online identification. The identification and control processes involved filtration using differential filters, which provided appropriate derivatives of signals. Proportional integral derivative (PID) controller tuning was performed using the Gauss–Newton optimisation procedure on the plant. Differential filters played a crucial role in all the developed control systems by significantly reducing measurement noise. The results showed that the performance of classical PID controllers can be improved by using differential filters and gain scheduling. The control and identification algorithms were implemented in an National Instruments (NI) myRIO-1900 controller. The nonlinear model of the plant was built based on Newton’s equations.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139140267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zbigniew Tyfa, P. Reorowicz, D. Obidowski, K. Jóźwik
Abstract Results obtained with computational fluid dynamics (CFD) rely on assumptions made during a pre-processing stage, including a mathematical description of a fluid rheology. Up to this date there is no clear answer to several aspects, mainly related to the question of whether and under what conditions blood can be simplified to a Newtonian fluid during CFD analyses. Different research groups present contradictory results, leaving the question unanswered. Therefore, the objective of this research was to perform steady-state and pulsatile blood flow simulations using eight different rheological models in geometries of varying complexity. A qualitative comparison of shear- and viscosity-related parameters showed no meaningful discrepancies, but a quantitative analysis revealed significant differences, especially in the magnitudes of wall shear stress (WSS) and its gradient (WSSG). We suggest that for the large arteries blood should be modelled as a non-Newtonian fluid, whereas for the cerebral vasculature the assumption of blood as a simple Newtonian fluid can be treated as a valid simplification.
{"title":"Influence of Fluid Rheology on Blood Flow Haemodynamics in Patient-Specific Arterial Networks of Varied Complexity – In-Silico Studies","authors":"Zbigniew Tyfa, P. Reorowicz, D. Obidowski, K. Jóźwik","doi":"10.2478/ama-2024-0002","DOIUrl":"https://doi.org/10.2478/ama-2024-0002","url":null,"abstract":"Abstract Results obtained with computational fluid dynamics (CFD) rely on assumptions made during a pre-processing stage, including a mathematical description of a fluid rheology. Up to this date there is no clear answer to several aspects, mainly related to the question of whether and under what conditions blood can be simplified to a Newtonian fluid during CFD analyses. Different research groups present contradictory results, leaving the question unanswered. Therefore, the objective of this research was to perform steady-state and pulsatile blood flow simulations using eight different rheological models in geometries of varying complexity. A qualitative comparison of shear- and viscosity-related parameters showed no meaningful discrepancies, but a quantitative analysis revealed significant differences, especially in the magnitudes of wall shear stress (WSS) and its gradient (WSSG). We suggest that for the large arteries blood should be modelled as a non-Newtonian fluid, whereas for the cerebral vasculature the assumption of blood as a simple Newtonian fluid can be treated as a valid simplification.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139138363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Vibration analysis of industrial robots is one of the key issues in the context of robotisation of machining processes. Low-frequency vibrations result from flexibility in manipulator joints. Within the scope of the article, a model of a two-link robot manipulator was built. Dynamic equations of motion were formulated to study the influence of the robot arm configuration on vibration effects. Based on numerical simulations, the frequency spectrum of vibrations of the robot’s links was determined, and tests were carried out in a number of configurations, obtaining a map of resonant frequencies depending on the configuration of the manipulator. Experimental studies were then carried out, which confirmed the conclusions from the simulation studies. The results obtained confirm that the positioning of the manipulator’s links has a significant effect on vibration effects. Tests conducted using a vision system with a motion amplification application made it easier to interpret the results. The formulated mathematical model of the manipulator generates results that coincide with the results of experimental studies.
{"title":"Influence of the Manipulator Configuration on Vibration Effects","authors":"Paulina Pietruś, P. Gierlak","doi":"10.2478/ama-2023-0060","DOIUrl":"https://doi.org/10.2478/ama-2023-0060","url":null,"abstract":"Abstract Vibration analysis of industrial robots is one of the key issues in the context of robotisation of machining processes. Low-frequency vibrations result from flexibility in manipulator joints. Within the scope of the article, a model of a two-link robot manipulator was built. Dynamic equations of motion were formulated to study the influence of the robot arm configuration on vibration effects. Based on numerical simulations, the frequency spectrum of vibrations of the robot’s links was determined, and tests were carried out in a number of configurations, obtaining a map of resonant frequencies depending on the configuration of the manipulator. Experimental studies were then carried out, which confirmed the conclusions from the simulation studies. The results obtained confirm that the positioning of the manipulator’s links has a significant effect on vibration effects. Tests conducted using a vision system with a motion amplification application made it easier to interpret the results. The formulated mathematical model of the manipulator generates results that coincide with the results of experimental studies.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139192629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The paper presents the results of the numerical analysis of the stability of C-section profiles together with the determination of the influence of the geometrical parameters of the holes and their arrangement on the strength properties of the profile, made of multilayer composite materials in a symmetrical arrangement of layers, which is deformed under the influence of the compressive force. Numerical calculations were carried out in the linear range (solution of the eigenvalue problem - critical state) using the finite element method (FEM) using the ABAQUS calculation package. Based on the obtained results, it was possible to determine the influence of the type and number of holes, their arrangement and geometric dimensions on the values of critical loads as well as the buckling modes of the profiles.
摘要 本文介绍了对 C 截面型材稳定性的数值分析结果，以及孔的几何参数及其排列对型材强度特性影响的确定。使用 ABAQUS 计算软件包的有限元法（FEM）在线性范围内进行了数值计算（特征值问题的求解-临界状态）。根据所得结果，可以确定孔的类型和数量、排列方式和几何尺寸对临界载荷值以及型材屈曲模式的影响。
{"title":"Linear Analysis of Thin-Walled Composite Profiles Weakened by Holes","authors":"K. Falkowicz","doi":"10.2478/ama-2023-0064","DOIUrl":"https://doi.org/10.2478/ama-2023-0064","url":null,"abstract":"Abstract The paper presents the results of the numerical analysis of the stability of C-section profiles together with the determination of the influence of the geometrical parameters of the holes and their arrangement on the strength properties of the profile, made of multilayer composite materials in a symmetrical arrangement of layers, which is deformed under the influence of the compressive force. Numerical calculations were carried out in the linear range (solution of the eigenvalue problem - critical state) using the finite element method (FEM) using the ABAQUS calculation package. Based on the obtained results, it was possible to determine the influence of the type and number of holes, their arrangement and geometric dimensions on the values of critical loads as well as the buckling modes of the profiles.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139195360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The present experimental research work aims to elaborate a new composite material (CM) composed of plasters reinforced with mats of long unidirectional luffa sponge fibres, treated chemically by 1% NaOH solution during 90 min at a temperature of 50°C, in orderto improve its thermomechanical and physical properties. The influence of fibre mat and fibre napping numbers of luffa sponge on density, porosity, flexural strength, thermal conductivity, thermal diffusivity, thermal effusivity and specific heat capacity properties was investigatedto lower building energy consumption. As far as our case is concerned, we processed a composite using single, double and triple-layer luffa sponge fibre mats. In our study, we are basically confined our experiments to three-layer mats. The experimental results revealed that the networking structure of fibres increases the flexural strength and decreases the thermal conductivity for a two-layer fibre wire mesh imbedded in the plaster matrix as compared with the neat plaster. However, there is a decrease in strength for a triple-layer composite, which referred to poor wetting of the fiber with the matrix material.
{"title":"Effect of Luffa Sponge Fibre Mats Embedded in the Plaster Matrix","authors":"Khaled Kharrati, Madiha Salhi, Abdelmoumen Hidouri, Ridha Abdeljabar","doi":"10.2478/ama-2023-0061","DOIUrl":"https://doi.org/10.2478/ama-2023-0061","url":null,"abstract":"Abstract The present experimental research work aims to elaborate a new composite material (CM) composed of plasters reinforced with mats of long unidirectional luffa sponge fibres, treated chemically by 1% NaOH solution during 90 min at a temperature of 50°C, in orderto improve its thermomechanical and physical properties. The influence of fibre mat and fibre napping numbers of luffa sponge on density, porosity, flexural strength, thermal conductivity, thermal diffusivity, thermal effusivity and specific heat capacity properties was investigatedto lower building energy consumption. As far as our case is concerned, we processed a composite using single, double and triple-layer luffa sponge fibre mats. In our study, we are basically confined our experiments to three-layer mats. The experimental results revealed that the networking structure of fibres increases the flexural strength and decreases the thermal conductivity for a two-layer fibre wire mesh imbedded in the plaster matrix as compared with the neat plaster. However, there is a decrease in strength for a triple-layer composite, which referred to poor wetting of the fiber with the matrix material.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139188649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The non-integer order derivatives, Caputo (C) and Caputo Fabrizio (CF), were employed to analyse the natural convective flow of magnetohydrodynamic (MHD) Jeffrey fluid. The aim is to generalise the idea of Jeffrey’s fluid flow. The fluid flow is elaborated between two vertical parallel plates. One plate is kept fixed while the other is moving with the velocity U0f(t), which induces the motion in the fluid. The fluid flow problem is modelled in terms of the partial differential equation along with generalised physical conditions. The appropriate parameters are introduced to the dimensionless system of equations. To obtain the solutions, the Laplace transform (LT) is operated on the fractional system of equations, and the results are presented in series form. The pertinent parameter’s influence on the fluid flow is brought under consideration to reveal interesting results. In comparison, we noticed that the C approach shows better results than CF, and graphs are drawn to show the results. The results for ordinary Jeffrey fluid, second-grade and viscous fluid are obtained in a limiting sense.
{"title":"Exact Analysis of Fractionalised Jeffrey Fluid in a Channel with Caputo and Caputo Fabrizio Time Derivative: A Comparative Study","authors":"Maryam Asgir, M. B. Riaz, Ayesha Islam","doi":"10.2478/ama-2023-0068","DOIUrl":"https://doi.org/10.2478/ama-2023-0068","url":null,"abstract":"Abstract The non-integer order derivatives, Caputo (C) and Caputo Fabrizio (CF), were employed to analyse the natural convective flow of magnetohydrodynamic (MHD) Jeffrey fluid. The aim is to generalise the idea of Jeffrey’s fluid flow. The fluid flow is elaborated between two vertical parallel plates. One plate is kept fixed while the other is moving with the velocity U0f(t), which induces the motion in the fluid. The fluid flow problem is modelled in terms of the partial differential equation along with generalised physical conditions. The appropriate parameters are introduced to the dimensionless system of equations. To obtain the solutions, the Laplace transform (LT) is operated on the fractional system of equations, and the results are presented in series form. The pertinent parameter’s influence on the fluid flow is brought under consideration to reveal interesting results. In comparison, we noticed that the C approach shows better results than CF, and graphs are drawn to show the results. The results for ordinary Jeffrey fluid, second-grade and viscous fluid are obtained in a limiting sense.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139188571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A control strategy is derived for fractional-order dynamic systems with Caputo derivative to guarantee collision-free trajectories for two agents. To guarantee that one agent keeps the state of the system out of a given set regardless of the other agent’s actions a Lyapunov-based approach is adopted. As a special case showing that the given approach to choosing proposed strategy is constructive for a fractional-order system with the Caputo derivative, a linear system as an example is discussed. Obtained results extend to the fractional order case the avoidance problem Leitman’s and Skowronski’s approach.
{"title":"Avoidence Strategies for Fractional Order Systems with Caputo Derivative","authors":"E. Pawłuszewicz","doi":"10.2478/ama-2023-0066","DOIUrl":"https://doi.org/10.2478/ama-2023-0066","url":null,"abstract":"Abstract A control strategy is derived for fractional-order dynamic systems with Caputo derivative to guarantee collision-free trajectories for two agents. To guarantee that one agent keeps the state of the system out of a given set regardless of the other agent’s actions a Lyapunov-based approach is adopted. As a special case showing that the given approach to choosing proposed strategy is constructive for a fractional-order system with the Caputo derivative, a linear system as an example is discussed. Obtained results extend to the fractional order case the avoidance problem Leitman’s and Skowronski’s approach.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139194904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yaşar Sert, T. Küçükömeroğlu, Hojjat Ghahramanzadeh Asl, L. Kara
Abstract The present study aims to determine the effect of target voltage of boron on elevated temperature wear behaviour of newly designed (Ti, Cr, Nb)-hBN PVD coatings. For this purpose, this layer is grown on the AISI L6 (55NiCrMoV7) at various target voltages (600 V, 700 V) using a high-power impulse magnetron sputtering setup. The coating layer has a graded design and has been coated on the substrate surface in adherence with the following order: Cr – CrN – TiCrN – TiCrNbN and finally TiCrNb-hBN (constituting the working layer). The surface properties of the layer were determined using SEM and an optical profilometer. It is seen that the coatings were deposited on the surface in a granular structure pattern away from the deposition defect (such as a droplet or hole), and the roughness values increase as the target voltage increases. Phase analysis is determined using XRD, and average grain size calculations are performed using the XRD data. The coating layer has grown on the surface at TiN (112), CrN (311), NbN (111) and h-BN (001) orientations. Then, mechanical tests including microhardness and scratch tests were conducted on the specimens. Although the layer that is produced with both different parameters improves the hardness of the substrate (4.7 GPa), the hardness of the coating layer at the voltage of 700 V (24.67 GPa) is higher than that of others. Based on scratch tests, scratch crack propagation resistance (CPR) values were determined as 40 N2 and 1,650 N2 for coatings produced at 600 V and 700 V, respectively. The wear behaviours of specimens are specified using a ball-on-disc type tribometer at 450°C. It is seen that the coating with high hardness and scratch resistance offers unique contributions to the wear performance of the substrate. The optimum value of the target voltage to be used in the production of this innovative coating has been introduced into the literature.
{"title":"The Effect of “B” Target Voltage on Wear Properties of TiCrNb-hBN Coatings","authors":"Yaşar Sert, T. Küçükömeroğlu, Hojjat Ghahramanzadeh Asl, L. Kara","doi":"10.2478/ama-2023-0067","DOIUrl":"https://doi.org/10.2478/ama-2023-0067","url":null,"abstract":"Abstract The present study aims to determine the effect of target voltage of boron on elevated temperature wear behaviour of newly designed (Ti, Cr, Nb)-hBN PVD coatings. For this purpose, this layer is grown on the AISI L6 (55NiCrMoV7) at various target voltages (600 V, 700 V) using a high-power impulse magnetron sputtering setup. The coating layer has a graded design and has been coated on the substrate surface in adherence with the following order: Cr – CrN – TiCrN – TiCrNbN and finally TiCrNb-hBN (constituting the working layer). The surface properties of the layer were determined using SEM and an optical profilometer. It is seen that the coatings were deposited on the surface in a granular structure pattern away from the deposition defect (such as a droplet or hole), and the roughness values increase as the target voltage increases. Phase analysis is determined using XRD, and average grain size calculations are performed using the XRD data. The coating layer has grown on the surface at TiN (112), CrN (311), NbN (111) and h-BN (001) orientations. Then, mechanical tests including microhardness and scratch tests were conducted on the specimens. Although the layer that is produced with both different parameters improves the hardness of the substrate (4.7 GPa), the hardness of the coating layer at the voltage of 700 V (24.67 GPa) is higher than that of others. Based on scratch tests, scratch crack propagation resistance (CPR) values were determined as 40 N2 and 1,650 N2 for coatings produced at 600 V and 700 V, respectively. The wear behaviours of specimens are specified using a ball-on-disc type tribometer at 450°C. It is seen that the coating with high hardness and scratch resistance offers unique contributions to the wear performance of the substrate. The optimum value of the target voltage to be used in the production of this innovative coating has been introduced into the literature.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper is focusses on developing a novel method for vibration damage estimation for military helicopters, fighter aircrafts and any other aircraft exposed to combined stochastic and deterministic loading. The first stage of the research focused on frequency domain damage prediction, which is the legacy method proposed by Bishop and developed by Sweitzer, Schlesinger, Woodward, Kerr, Murthy, Datta and, Atkins. The mentioned frequency domain-based method is used in commercial software, e.g., MSC CAE Fatigue. Frequency domain damage prediction is based on superposition of spectral moments and Dirlik method of Rainflow Cycle Counting algorithm in frequency domain. The first phase of the research showed the legacy algorithm based on transfer function developed using FEM (Finite Element Method) method in Abaqus environment and is very conservative. The second stage of the research aims to develop a novel method which allowing for more robust and accurate damage estimation. For this purpose, the Monte Carlo method for retrieving random signal in the time domain from signal in frequency domain was used. To obtain the system transfer function, – the 1 g load harmonic system response was obtained using FEM analysis. It was subsequently scaled linearly by the PSD input curve for random loading and sine wave, or sine sweep function for deterministic loading to calculate the cumulative system response of the linear system. The research allows the development of a novel method to precisely estimate vibration damage using combined time and frequency domains approach, based on effective frequency domain FEM analysis of the linear system. The new proposed method can be also used for precise replication of test conditions via considering signal clipping and frequency resolution used for real testing.
{"title":"Using Computer Technique for Developing Method for Vibration Damage Estimation Under Combined Random and Deterministic Loading","authors":"Michał Ptak, Jerzy Czmochowski","doi":"10.2478/ama-2023-0065","DOIUrl":"https://doi.org/10.2478/ama-2023-0065","url":null,"abstract":"Abstract This paper is focusses on developing a novel method for vibration damage estimation for military helicopters, fighter aircrafts and any other aircraft exposed to combined stochastic and deterministic loading. The first stage of the research focused on frequency domain damage prediction, which is the legacy method proposed by Bishop and developed by Sweitzer, Schlesinger, Woodward, Kerr, Murthy, Datta and, Atkins. The mentioned frequency domain-based method is used in commercial software, e.g., MSC CAE Fatigue. Frequency domain damage prediction is based on superposition of spectral moments and Dirlik method of Rainflow Cycle Counting algorithm in frequency domain. The first phase of the research showed the legacy algorithm based on transfer function developed using FEM (Finite Element Method) method in Abaqus environment and is very conservative. The second stage of the research aims to develop a novel method which allowing for more robust and accurate damage estimation. For this purpose, the Monte Carlo method for retrieving random signal in the time domain from signal in frequency domain was used. To obtain the system transfer function, – the 1 g load harmonic system response was obtained using FEM analysis. It was subsequently scaled linearly by the PSD input curve for random loading and sine wave, or sine sweep function for deterministic loading to calculate the cumulative system response of the linear system. The research allows the development of a novel method to precisely estimate vibration damage using combined time and frequency domains approach, based on effective frequency domain FEM analysis of the linear system. The new proposed method can be also used for precise replication of test conditions via considering signal clipping and frequency resolution used for real testing.","PeriodicalId":44942,"journal":{"name":"Acta Mechanica et Automatica","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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