In this paper, the application possibilities of the ultra-high strength (UHSS) Domex 960 steel in the underwater welded structures are analyzed. In the research, the investigated material has been tested in bead-on-plate wet welding conditions with the usage of different heat input values, namely 0.63 kJ/mm, 0.72 kJ/mm and 0.93 kJ/mm. Specimens were performed by the manual metal arc (MMA) welding method with the usage of rutile covered electrodes. Firstly, the nondestructive visual testing (VT) was carried out. In the next step, the metallographic macro- and microscopic tests were performed. Finally, the hardness of the weld metal and heat-affected zone (HAZ) was measured by the Vickers HV10 method. The performed experiments allow the statement that the Domex 960 steel could be welded in a water environment. It also showed that increasing heat input leads to decreasing the hardness in HAZ by 30 HV10. It may result in decreasing the susceptibility to cold cracking during butt- and filet welding in the water environment.
{"title":"APPLICATION POSSIBILITIES OF THE S960 STEEL IN UNDERWATER WELDED STRUCTURES","authors":"J. Tomków, M. Landowski, G. Rogalski","doi":"10.22190/fume210722066t","DOIUrl":"https://doi.org/10.22190/fume210722066t","url":null,"abstract":"In this paper, the application possibilities of the ultra-high strength (UHSS) Domex 960 steel in the underwater welded structures are analyzed. In the research, the investigated material has been tested in bead-on-plate wet welding conditions with the usage of different heat input values, namely 0.63 kJ/mm, 0.72 kJ/mm and 0.93 kJ/mm. Specimens were performed by the manual metal arc (MMA) welding method with the usage of rutile covered electrodes. Firstly, the nondestructive visual testing (VT) was carried out. In the next step, the metallographic macro- and microscopic tests were performed. Finally, the hardness of the weld metal and heat-affected zone (HAZ) was measured by the Vickers HV10 method. The performed experiments allow the statement that the Domex 960 steel could be welded in a water environment. It also showed that increasing heat input leads to decreasing the hardness in HAZ by 30 HV10. It may result in decreasing the susceptibility to cold cracking during butt- and filet welding in the water environment.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91236616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Hamiltonian-based frequency formulation has been hailed as an unprecedented success for it gives a straightforward insight into a complex nonlinear vibration system with simple calculation. This paper gives a systematical analysis of the formulation, and two simplified formulations are suggested. The cubic-quintic Duffing oscillator is used as an example to show extremely simple calculation and remarkable accuracy. It can be used as a paradigm for many other applications, and the one-step solving process has cleaned up the road of the nonlinear vibration theory.
{"title":"SIMPLIFIED HAMILTONIAN-BASED FREQUENCY-AMPLITUDE FORMULATION FOR NONLINEAR VIBRATION SYSTEMS","authors":"Hong-ping Ma","doi":"10.22190/fume220420023m","DOIUrl":"https://doi.org/10.22190/fume220420023m","url":null,"abstract":"The Hamiltonian-based frequency formulation has been hailed as an unprecedented success for it gives a straightforward insight into a complex nonlinear vibration system with simple calculation. This paper gives a systematical analysis of the formulation, and two simplified formulations are suggested. The cubic-quintic Duffing oscillator is used as an example to show extremely simple calculation and remarkable accuracy. It can be used as a paradigm for many other applications, and the one-step solving process has cleaned up the road of the nonlinear vibration theory. ","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76680466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yongliang Yuan, Jianli Ren, Zhenxi Wang, Xiaokai Mu
In this paper, the excavator’s dynamic performance is considered together with the study of its trajectory, stress distribution and vibration. Many researchers have focused their study on the kinematics principle while a few others focused their work on dynamic performance, especially the vibration analysis. Previous studies of dynamic performance analysis have ignored the vibration effects. To address these challenges, the rigid-flexible coupling model of the excavator attachment is established and carried out based on virtual prototyping in this study. The dipper handle, the boom and the hoist rope are modeled as a flexible multi-body system for structural strength. The other components are modeled as a rigid multi-body system to catch the dynamic characteristics. The results show that the number of flexible bodies has little effect on the excavation trajectory. The maximum stress determined for the dipper handle and the boom are 96.45 MPa and 212.24 MPa, respectively. The dynamic performance of the excavator is greatly influenced by the clearance and is characterized by two phases: as the clearance decreases, the dynamic response decreases at first and then increases.
{"title":"DYNAMIC ANALYSIS OF THE RIGID-FLEXIBLE EXCAVATOR MECHANISM BASED ON VIRTUAL PROTOTYPE","authors":"Yongliang Yuan, Jianli Ren, Zhenxi Wang, Xiaokai Mu","doi":"10.22190/fume211028008y","DOIUrl":"https://doi.org/10.22190/fume211028008y","url":null,"abstract":"In this paper, the excavator’s dynamic performance is considered together with the study of its trajectory, stress distribution and vibration. Many researchers have focused their study on the kinematics principle while a few others focused their work on dynamic performance, especially the vibration analysis. Previous studies of dynamic performance analysis have ignored the vibration effects. To address these challenges, the rigid-flexible coupling model of the excavator attachment is established and carried out based on virtual prototyping in this study. The dipper handle, the boom and the hoist rope are modeled as a flexible multi-body system for structural strength. The other components are modeled as a rigid multi-body system to catch the dynamic characteristics. The results show that the number of flexible bodies has little effect on the excavation trajectory. The maximum stress determined for the dipper handle and the boom are 96.45 MPa and 212.24 MPa, respectively. The dynamic performance of the excavator is greatly influenced by the clearance and is characterized by two phases: as the clearance decreases, the dynamic response decreases at first and then increases.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86431837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Safaei, Emmanuel Chukwueloka Onyibo, Dogus Hurdoganoglu
The aim of this paper is to present a proposed honeycomb core shape and compare it with a normal hexagonal shape core in a sandwich beam. The sandwich cores are simulated in finite element with different materials; aluminum and epoxy-carbon with six layers are used as face sheet and the results are compared to those obtained theoretically. Simulation of 3-point bending test is performed in commercial software ANSYS to verify the analytical results with the numerical ones. Hence, for simplicity one layer of the skin is used on the equivalent model of sandwich for lesser computational time and more accurate evaluation. Simulation of harmonic analysis of hexagonal core and proposed core shape is carried out in frequency domain to identify the core with less deformation under high frequency and it can withstand harmful effects. The proposed core shape model having the same cell numbers and material as the normal hexagonal model is compared with experimental results; it is observed that the proposed core shape model has good flexural stiffness, resonance, fatigue, and stress resistance at a higher frequency.
{"title":"EFFECT OF STATIC AND HARMONIC LOADING ON THE HONEYCOMB SANDWICH BEAM BY USING FINITE ELEMENT METHOD","authors":"B. Safaei, Emmanuel Chukwueloka Onyibo, Dogus Hurdoganoglu","doi":"10.22190/fume220201009s","DOIUrl":"https://doi.org/10.22190/fume220201009s","url":null,"abstract":"The aim of this paper is to present a proposed honeycomb core shape and compare it with a normal hexagonal shape core in a sandwich beam. The sandwich cores are simulated in finite element with different materials; aluminum and epoxy-carbon with six layers are used as face sheet and the results are compared to those obtained theoretically. Simulation of 3-point bending test is performed in commercial software ANSYS to verify the analytical results with the numerical ones. Hence, for simplicity one layer of the skin is used on the equivalent model of sandwich for lesser computational time and more accurate evaluation. Simulation of harmonic analysis of hexagonal core and proposed core shape is carried out in frequency domain to identify the core with less deformation under high frequency and it can withstand harmful effects. The proposed core shape model having the same cell numbers and material as the normal hexagonal model is compared with experimental results; it is observed that the proposed core shape model has good flexural stiffness, resonance, fatigue, and stress resistance at a higher frequency.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90986165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work is devoted to the study of a one-dimensional phenomenological model of a focal defect regenerative rehabilitation in the articular cartilage. The model is based on six differential equations in partial derivatives of the “Diffusion-Reaction” type, which was previously used by a number of authors to study cellular processes in various tissues under cell therapy conditions. To take into account the influence of moderate mechanical stimulation of immature tissue, an indirect approach was used, as a result of which some model parameters that directly affect cell proliferation and differentiation were varied considering experimental data. The results of the model study show that moderate stimulation of immature tissue in the early stages of repair the focal articular cartilage defect under conditions of cell therapy leads to an intensification of regenerative processes in the tissue and promotes more rapid formation of the extracellular matrix.
{"title":"ONE-DIMENSIONAL BIOLOGICAL MODEL OF SYNOVIAL JOINTS REGENERATIVE REHABILITATION IN OSTEOARTHRITIS","authors":"V. Popov, Aleksandr M. Poliakov, V. Pakhaliuk","doi":"10.22190/fume220203014p","DOIUrl":"https://doi.org/10.22190/fume220203014p","url":null,"abstract":"This work is devoted to the study of a one-dimensional phenomenological model of a focal defect regenerative rehabilitation in the articular cartilage. The model is based on six differential equations in partial derivatives of the “Diffusion-Reaction” type, which was previously used by a number of authors to study cellular processes in various tissues under cell therapy conditions. To take into account the influence of moderate mechanical stimulation of immature tissue, an indirect approach was used, as a result of which some model parameters that directly affect cell proliferation and differentiation were varied considering experimental data. The results of the model study show that moderate stimulation of immature tissue in the early stages of repair the focal articular cartilage defect under conditions of cell therapy leads to an intensification of regenerative processes in the tissue and promotes more rapid formation of the extracellular matrix.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87151578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study aims at investigating effectiveness of the quadruple (early-pilot-main-after [epMa]) injection strategy over three different triple [early-main-after (eMa), early-pilot-main (epM) and pilot-main-after (pMa)] injection scheduling in terms of emissions, performance [brake specific fuel consumption (BSFC), torque, brake thermal efficiency (BTE) and fuel economy] and noise. The experimentation was carried out on a heavy-duty BS-IV diesel engine with 45% EGR fraction and fixed main injection (Crank-angle) scheduling at eight different RPMs and three loads of engine (20%, 60% and 100%) using design of experiments(DOE). This comprehensive study showed that the quadruple injection strategy provides optimum results in both performance and emissions compared to the promising three triple injection strategy. The quadruple injection strategy exhibits the best BTE at all operating conditions and best BSFC at medium to high-speed zone around 0.5–1% inline to reduce combustion noise (CN) level, especially at low speeds and low to medium load of 0.2–2.2 dBA. Among triple injections, the pMa shows the best performance in BSFC, BTE, smoke and THC emissions. The epM is the best in the CO emissions and torque performance in the low-speed zone. Smoke value is marginally higher for the epMa at low to medium speed than the pMa, although average smoke emissions were the best. Taken together, the overall PM emission level was marginally better than Triple Injections, due to the impact of double pilots in combination with post-injection. In addition, NOx emissions were improved (around 3–6%) significantly with quadruple than with triple injections. The epMa injection scheduling also showed improvement in constant speed fuel economy and in pass-by-noise at the vehicle.
本研究旨在通过三种不同的三种[早期主-后(eMa)、早期主-后(epM)和早期主-后(pMa)]喷射计划，研究四重(早期先导-主-后)喷射策略在排放、性能(制动比油耗(BSFC)、扭矩、制动热效率(BTE)和燃油经济性)和噪音方面的有效性。实验采用DOE设计(design of experiments, DOE)，在EGR分数为45%、主喷射(曲柄角)调度固定的重型BS-IV柴油机上，在8种不同转速、20%、60%和100%发动机负荷下进行。这项综合研究表明，与前景看好的三次三次喷射策略相比，四次喷射策略在性能和排放方面都具有最佳效果。四缸喷射策略在所有工况下都表现出最佳的BTE，在中高速区域的最佳BSFC约为0.5-1%，以降低燃烧噪声(CN)水平，特别是在低速和0.2-2.2 dBA的中低负荷下。在三次注入中，pMa在BSFC、BTE、smoke和THC排放方面表现最佳。epM在低速区CO排放和扭矩性能最好。低至中速时，epMa的烟雾值略高于pMa，尽管平均烟雾排放量最好。综上所述，由于双重驾驶员和后注射的影响，总体PM排放水平略好于三重注射。此外，与三次注入相比，四次注入能显著改善氮氧化物排放量(约3-6%)。epMa喷射调度也显示出等速燃油经济性和车辆通过噪声的改善。
{"title":"ASSESSMENT OF THE QUADRUPLE INJECTION STRATEGY OVER TRIPLE INJECTIONS TO IMPROVE EMISSIONS, PERFORMANCE AND NOISE OF THE AUTOMOTIVE DIESEL ENGINE","authors":"S. Biswas, A. Mukhopadhyay","doi":"10.22190/fume210329049b","DOIUrl":"https://doi.org/10.22190/fume210329049b","url":null,"abstract":"The present study aims at investigating effectiveness of the quadruple (early-pilot-main-after [epMa]) injection strategy over three different triple [early-main-after (eMa), early-pilot-main (epM) and pilot-main-after (pMa)] injection scheduling in terms of emissions, performance [brake specific fuel consumption (BSFC), torque, brake thermal efficiency (BTE) and fuel economy] and noise. The experimentation was carried out on a heavy-duty BS-IV diesel engine with 45% EGR fraction and fixed main injection (Crank-angle) scheduling at eight different RPMs and three loads of engine (20%, 60% and 100%) using design of experiments(DOE). This comprehensive study showed that the quadruple injection strategy provides optimum results in both performance and emissions compared to the promising three triple injection strategy. The quadruple injection strategy exhibits the best BTE at all operating conditions and best BSFC at medium to high-speed zone around 0.5–1% inline to reduce combustion noise (CN) level, especially at low speeds and low to medium load of 0.2–2.2 dBA. Among triple injections, the pMa shows the best performance in BSFC, BTE, smoke and THC emissions. The epM is the best in the CO emissions and torque performance in the low-speed zone. Smoke value is marginally higher for the epMa at low to medium speed than the pMa, although average smoke emissions were the best. Taken together, the overall PM emission level was marginally better than Triple Injections, due to the impact of double pilots in combination with post-injection. In addition, NOx emissions were improved (around 3–6%) significantly with quadruple than with triple injections. The epMa injection scheduling also showed improvement in constant speed fuel economy and in pass-by-noise at the vehicle.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88948622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Stojković, M. Trifunovic, J. Milovanovic, S. Arsic
There is a growing demand for application of personalized bone implants (endoprostheses or macro-scaffolds, and fixators) which conform the anatomy of patient. Hence the need for a CAD procedure that enables fast and sufficiently accurate digital reconstruction of the traumatized bone geometry. Research presented in this paper addresses digital reconstruction of the femoral neck fracture. The results point out that User-Defined (geometric) Feature (UDF) concept is the most convenient to use in digital reconstruction of numerous variants of the same topology, such as in this kind of bone region. UDF, named FemoNeck, is developed to demonstrate capability of the chosen concept. Its geometry, controlled by a dozen of parameters, can be easily shaped according to anatomy of femoral neck region of the specific patient. That kind of CAD procedure should use minimally required set of geometric (anatomical) parameters, which can be easily captured from X-ray or Computed Tomography (CT) images. For the statistical analysis of geometry and UDF development we used CT scans of proximal femur of 24 Caucasian female and male adults. The validation of the proposed method was done by applying it for remodeling four femoral necks of four different proximal femurs and by comparing the geometrical congruency between the raw polygonal models gained directly from CT scan and reconstructed models.
{"title":"USER DEFINED GEOMETRIC FEATURE FOR THE CREATION OF THE FEMORAL NECK ENVELOPING SURFACE","authors":"M. Stojković, M. Trifunovic, J. Milovanovic, S. Arsic","doi":"10.22190/fume200220034s","DOIUrl":"https://doi.org/10.22190/fume200220034s","url":null,"abstract":"There is a growing demand for application of personalized bone implants (endoprostheses or macro-scaffolds, and fixators) which conform the anatomy of patient. Hence the need for a CAD procedure that enables fast and sufficiently accurate digital reconstruction of the traumatized bone geometry. Research presented in this paper addresses digital reconstruction of the femoral neck fracture. The results point out that User-Defined (geometric) Feature (UDF) concept is the most convenient to use in digital reconstruction of numerous variants of the same topology, such as in this kind of bone region. UDF, named FemoNeck, is developed to demonstrate capability of the chosen concept. Its geometry, controlled by a dozen of parameters, can be easily shaped according to anatomy of femoral neck region of the specific patient. That kind of CAD procedure should use minimally required set of geometric (anatomical) parameters, which can be easily captured from X-ray or Computed Tomography (CT) images. For the statistical analysis of geometry and UDF development we used CT scans of proximal femur of 24 Caucasian female and male adults. The validation of the proposed method was done by applying it for remodeling four femoral necks of four different proximal femurs and by comparing the geometrical congruency between the raw polygonal models gained directly from CT scan and reconstructed models.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90508153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Harouz, A. Lakehal, K. Khelil, O. Dedry, N. Hashemi, S. Boudebane
The paper examines the friction and wear behavior of four different WC/TiC-Co cermets, where three of them are composed of 5%, 10% and 15% TiC additions, and a WC-Co grade without TiC, taken as a reference material for comparison purpose. The principal aim is to improve wear resistance to high sliding speeds (hot rolling) of the WC-Co material as a reference by adding previously-listed percentage of TiC. The samples (cermets) were prepared according to the powder metallurgy procedure, which includes the preparation of the powder mixture, its compression shaping and liquid phase sintering. Sintering was carried out at 1460 ° C, for 14 hours, in a reducing medium (H2). The TiC materials are added in order to boost hardness of the WC-15Co cermet and, consequently, its resistance to wear under thermomechanical conditions. The experiments are conducted using a pin-on-disc tribometer in contact with Al2O3 alumina ball at two sliding speeds of 0.5m/s and 0.75m/s, at a high temperature of 450°C, and a 20 N load. It has been noticed that some recorded friction coefficients are unstable and exhibit many peaks during almost the whole friction test period. The obtained results from the SEM microscope show that the wear behavior of the new proposed material is improved, where it has been shown that, at the sliding speed of 0.75m/s, the greater the TiC percentage is, the lower the average friction coefficient will be. Also, for the speed of 0.5 m/s, the average friction coefficient is relatively more stable with the TiC percentage increase. Moreover, the obtained experimental results show an average wear rate decrease, with respect to reference grades (NA), that amounts to nearly 36% and 41% at the two sliding speeds P1 (0.5m/s) and P2 (0.75m/s), respectively.
{"title":"DRY SLIDING FRICTION AND WEAR OF THE WC/TIC-CO IN CONTACT WITH AL2O3 FOR TWO SLIDING SPEEDS","authors":"R. Harouz, A. Lakehal, K. Khelil, O. Dedry, N. Hashemi, S. Boudebane","doi":"10.22190/fume200310039h","DOIUrl":"https://doi.org/10.22190/fume200310039h","url":null,"abstract":"The paper examines the friction and wear behavior of four different WC/TiC-Co cermets, where three of them are composed of 5%, 10% and 15% TiC additions, and a WC-Co grade without TiC, taken as a reference material for comparison purpose. The principal aim is to improve wear resistance to high sliding speeds (hot rolling) of the WC-Co material as a reference by adding previously-listed percentage of TiC. The samples (cermets) were prepared according to the powder metallurgy procedure, which includes the preparation of the powder mixture, its compression shaping and liquid phase sintering. Sintering was carried out at 1460 ° C, for 14 hours, in a reducing medium (H2). The TiC materials are added in order to boost hardness of the WC-15Co cermet and, consequently, its resistance to wear under thermomechanical conditions. The experiments are conducted using a pin-on-disc tribometer in contact with Al2O3 alumina ball at two sliding speeds of 0.5m/s and 0.75m/s, at a high temperature of 450°C, and a 20 N load. It has been noticed that some recorded friction coefficients are unstable and exhibit many peaks during almost the whole friction test period. The obtained results from the SEM microscope show that the wear behavior of the new proposed material is improved, where it has been shown that, at the sliding speed of 0.75m/s, the greater the TiC percentage is, the lower the average friction coefficient will be. Also, for the speed of 0.5 m/s, the average friction coefficient is relatively more stable with the TiC percentage increase. Moreover, the obtained experimental results show an average wear rate decrease, with respect to reference grades (NA), that amounts to nearly 36% and 41% at the two sliding speeds P1 (0.5m/s) and P2 (0.75m/s), respectively.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75831176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article presents research on the erosion of the metamorphic rock - marble by the Abrasive Water Jet (AWJ). The fragmentation of abrasive grains during the erosion process is demonstrated. The effect of the cutting process's most important parameters as traverse speed, nozzle ID, and abrasive mass flow rate, on the maximum cutting depth, is shown. To create a mathematical-statistic model of the erosion process, the methodology of the response surface (RSM) was used for modeling. The polynomial equation of the second degree is chosen for developing the regression model. Studies have shown the optimal parameters of the process, to reach the highest depth of the cut. Additionally, the erosion wear of a focusing tube under different process conditions is presented.
{"title":"EXPERIMENTAL RESEARCH INTO MARBLE CUTTING BY ABRASIVE WATER JET","authors":"A. Perec, A. Radomska-Zalas, A. Fajdek-Bieda","doi":"10.22190/fume210203037p","DOIUrl":"https://doi.org/10.22190/fume210203037p","url":null,"abstract":"The article presents research on the erosion of the metamorphic rock - marble by the Abrasive Water Jet (AWJ). The fragmentation of abrasive grains during the erosion process is demonstrated. The effect of the cutting process's most important parameters as traverse speed, nozzle ID, and abrasive mass flow rate, on the maximum cutting depth, is shown. To create a mathematical-statistic model of the erosion process, the methodology of the response surface (RSM) was used for modeling. The polynomial equation of the second degree is chosen for developing the regression model. Studies have shown the optimal parameters of the process, to reach the highest depth of the cut. Additionally, the erosion wear of a focusing tube under different process conditions is presented.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79167551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In many tribological systems, an intermediate layer of a limited number of abrasive particles exist. Thereby, the resulting wear and friction phenomena are desirable in many manufacturing processes, such as lapping or polishing, whereas in machine elements, they are unwanted due to reducing lifetime or performance.For a better understanding of the contact phenomena and the interaction of tribological systems with an intermediate layer of a limited number of particles, fundamental investigations are carried out on a tribometer test rig. For this purpose, two test scenarios are investigated, a) the kinematics and contact forces of single geometrically defined particles such as dodecahedron, icosahedron and hexahedron, and b) the contact forces and surface roughness of a layer of silicon carbide particles of different sizes.The measured ratio of tangential to normal force can be used as an indicator of the dominating kinematics of the particles and of the generated surface roughness, respectively. The higher the force ratio, the higher the tendency to slide for a given particle type and paring of particle and counter body.For one geometrically defined particle the short-time Fourier transform additionally helps to distinguish the state of motion since the excited frequencies during rolling are reduced. For a layer of silicon carbide particles, the velocity and particle size have the strongest influence on the overall motion and the surface roughness produced. Larger particles tend to slide and create more scratches, while smaller particles tend to roll and create indentations in the counter body. Furthermore, for the same particle size, an increase in velocity causes a transition from sliding to rolling, resulting in an increased surface roughness.
{"title":"RELATION OF KINEMATICS AND CONTACT FORCES IN THREE-BODY SYSTEMS WITH A LIMITED NUMBER OF PARTICLES","authors":"Kristin M. de Payrebrune","doi":"10.22190/fume210310035p","DOIUrl":"https://doi.org/10.22190/fume210310035p","url":null,"abstract":"In many tribological systems, an intermediate layer of a limited number of abrasive particles exist. Thereby, the resulting wear and friction phenomena are desirable in many manufacturing processes, such as lapping or polishing, whereas in machine elements, they are unwanted due to reducing lifetime or performance.For a better understanding of the contact phenomena and the interaction of tribological systems with an intermediate layer of a limited number of particles, fundamental investigations are carried out on a tribometer test rig. For this purpose, two test scenarios are investigated, a) the kinematics and contact forces of single geometrically defined particles such as dodecahedron, icosahedron and hexahedron, and b) the contact forces and surface roughness of a layer of silicon carbide particles of different sizes.The measured ratio of tangential to normal force can be used as an indicator of the dominating kinematics of the particles and of the generated surface roughness, respectively. The higher the force ratio, the higher the tendency to slide for a given particle type and paring of particle and counter body.For one geometrically defined particle the short-time Fourier transform additionally helps to distinguish the state of motion since the excited frequencies during rolling are reduced. For a layer of silicon carbide particles, the velocity and particle size have the strongest influence on the overall motion and the surface roughness produced. Larger particles tend to slide and create more scratches, while smaller particles tend to roll and create indentations in the counter body. Furthermore, for the same particle size, an increase in velocity causes a transition from sliding to rolling, resulting in an increased surface roughness.","PeriodicalId":51338,"journal":{"name":"Facta Universitatis-Series Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":7.9,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84052118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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