Pub Date : 2024-04-04DOI: 10.3389/fmech.2024.1357087
Sujit Kumar, Sasanka Sekhor Sharma, J. Giri, Emad Makki, T. Sathish, Hitesh Panchal
Finding innovative, stable, and environmentally acceptable perovskite (PVK) sunlit absorber constituents has developed a major area of study in photovoltaics (PVs). As an alternative to lead-based organic-inorganic halide PVKs, these PVKs are being researched for use in cutting-edge PVK solar cells. While there has been progress in this field as of late, there are still several scientific and technical questions that have yet to be answered. Here, we offer insights into the big picture of PVK toxicity/instability research, and then we discuss methods for creating stable, non-toxic PVKs from scratch. It is also believed that the processing of the proposed PVKs, which occurs between materials design and actual devices, poses novel challenges. PVK PVs that are both stable and ecologically benign can be created if these topics receive more attention. It is interesting to note that although perovskite solar cells (PSCs) have impressive power conversion efficiency, their commercial adoption is hindered by lead toxicity. Lead is a hazardous material that can cause harm to humans and the environment. As a result, researchers worldwide are exploring non-toxic lead-free photovoltaics (PSCs) for a sustainable and safe environment. To achieve this goal, lead in PSCs is replaced by non-toxic or less harmful metals such as tin, germanium, titanium, silver, bismuth, and copper. A study has been conducted that provides information on the characteristics, sustainability, and obstacles of replacing lead with these metals in PSCs. The paper also explores solutions for stability and efficiency issues in lead-free, non-toxic PSC commercialization, including altering manufacturing techniques and adding additives. Lastly, it covers the latest developments/future perspectives in lead-free perovskite solar cells that can be implemented in lead-free PSCs.
{"title":"Perovskite materials with improved stability and environmental friendliness for photovoltaics","authors":"Sujit Kumar, Sasanka Sekhor Sharma, J. Giri, Emad Makki, T. Sathish, Hitesh Panchal","doi":"10.3389/fmech.2024.1357087","DOIUrl":"https://doi.org/10.3389/fmech.2024.1357087","url":null,"abstract":"Finding innovative, stable, and environmentally acceptable perovskite (PVK) sunlit absorber constituents has developed a major area of study in photovoltaics (PVs). As an alternative to lead-based organic-inorganic halide PVKs, these PVKs are being researched for use in cutting-edge PVK solar cells. While there has been progress in this field as of late, there are still several scientific and technical questions that have yet to be answered. Here, we offer insights into the big picture of PVK toxicity/instability research, and then we discuss methods for creating stable, non-toxic PVKs from scratch. It is also believed that the processing of the proposed PVKs, which occurs between materials design and actual devices, poses novel challenges. PVK PVs that are both stable and ecologically benign can be created if these topics receive more attention. It is interesting to note that although perovskite solar cells (PSCs) have impressive power conversion efficiency, their commercial adoption is hindered by lead toxicity. Lead is a hazardous material that can cause harm to humans and the environment. As a result, researchers worldwide are exploring non-toxic lead-free photovoltaics (PSCs) for a sustainable and safe environment. To achieve this goal, lead in PSCs is replaced by non-toxic or less harmful metals such as tin, germanium, titanium, silver, bismuth, and copper. A study has been conducted that provides information on the characteristics, sustainability, and obstacles of replacing lead with these metals in PSCs. The paper also explores solutions for stability and efficiency issues in lead-free, non-toxic PSC commercialization, including altering manufacturing techniques and adding additives. Lastly, it covers the latest developments/future perspectives in lead-free perovskite solar cells that can be implemented in lead-free PSCs.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140745453","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}
Pub Date : 2024-04-04DOI: 10.3389/fmech.2024.1391315
Govind Ghule, S. Sanap, S. Chinchanikar, R. Čep, Ajay Kumar, Suresh Y. Bhave, Rakesh Kumar, Faisal Altarazi
This study compares conventional turning (CT) and ultrasonic vibration-assisted turning (UVAT) in machining hardened AISI 52100 steel (62 HRC) with a PVD-coated TiAlSiN carbide tool. UVAT experiments, utilizing an ultrasonic frequency of 20 kHz and vibration amplitude of 20 µm, varied the cutting speed, feed, and depth of cut. Remarkably, UVAT reduced tool wear, extending tool longevity. Surprisingly, power consumption showed no significant differences between CT and UVAT. Mathematical models based on experimental data highlight the substantial impact of the cutting speed on tool wear, followed closely by the depth of cut. For power consumption, the depth of cut took precedence, with the cutting speed and feed rate playing pronounced roles in UVAT. This emphasizes the potential for further research on machinability, particularly exploring different vibration directions on the tool in feed, tangential, and radial aspects.
{"title":"Investigation of conventional and ultrasonic vibration-assisted turning of hardened steel using a coated carbide tool","authors":"Govind Ghule, S. Sanap, S. Chinchanikar, R. Čep, Ajay Kumar, Suresh Y. Bhave, Rakesh Kumar, Faisal Altarazi","doi":"10.3389/fmech.2024.1391315","DOIUrl":"https://doi.org/10.3389/fmech.2024.1391315","url":null,"abstract":"This study compares conventional turning (CT) and ultrasonic vibration-assisted turning (UVAT) in machining hardened AISI 52100 steel (62 HRC) with a PVD-coated TiAlSiN carbide tool. UVAT experiments, utilizing an ultrasonic frequency of 20 kHz and vibration amplitude of 20 µm, varied the cutting speed, feed, and depth of cut. Remarkably, UVAT reduced tool wear, extending tool longevity. Surprisingly, power consumption showed no significant differences between CT and UVAT. Mathematical models based on experimental data highlight the substantial impact of the cutting speed on tool wear, followed closely by the depth of cut. For power consumption, the depth of cut took precedence, with the cutting speed and feed rate playing pronounced roles in UVAT. This emphasizes the potential for further research on machinability, particularly exploring different vibration directions on the tool in feed, tangential, and radial aspects.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140744180","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}
Pub Date : 2024-04-02DOI: 10.3389/fmech.2024.1362431
Lundun Zhang, Teng Wan, Chunyou Zhang
Introduction: With the rapid development of the gearbox manufacturing industry, the internal gear response has received attention, and the control of meshing noise during gear operation has been studied. Conventional noise reduction methods are usually based on gear order, and with the improvement of gearbox manufacturing technology, this method gradually becomes difficult to cope with a wide range of data.Methods: To expand the search domain of noise control systems, this study combines gear response and gear order, and adds the condition of gear uniform load. For common noise reduction problems in composite systems, this study improves the time-varying stiffness excitation mechanism and generates a coupled system.Results: Finally, this study conducts experiments on the Gmnoi dataset and compares it with three systems including quantum genetics to verify the superiority of the proposed system. The suppression effects of the four systems on gear meshing noise were 98.4%, 95.8%, 93.5%, and 92.7%, respectively. Their highest performance for different gear groups was 623, 514, 406, and 423, respectively.Discussion: The experimental results showed that the proposed coupling system has strong robustness and high accuracy in controlling gearbox meshing noise, and is of great significance in reducing noise pollution and improving the working environment of the gearbox.
{"title":"The influence of gear load distribution based on coupled systems on gearbox meshing noise","authors":"Lundun Zhang, Teng Wan, Chunyou Zhang","doi":"10.3389/fmech.2024.1362431","DOIUrl":"https://doi.org/10.3389/fmech.2024.1362431","url":null,"abstract":"Introduction: With the rapid development of the gearbox manufacturing industry, the internal gear response has received attention, and the control of meshing noise during gear operation has been studied. Conventional noise reduction methods are usually based on gear order, and with the improvement of gearbox manufacturing technology, this method gradually becomes difficult to cope with a wide range of data.Methods: To expand the search domain of noise control systems, this study combines gear response and gear order, and adds the condition of gear uniform load. For common noise reduction problems in composite systems, this study improves the time-varying stiffness excitation mechanism and generates a coupled system.Results: Finally, this study conducts experiments on the Gmnoi dataset and compares it with three systems including quantum genetics to verify the superiority of the proposed system. The suppression effects of the four systems on gear meshing noise were 98.4%, 95.8%, 93.5%, and 92.7%, respectively. Their highest performance for different gear groups was 623, 514, 406, and 423, respectively.Discussion: The experimental results showed that the proposed coupling system has strong robustness and high accuracy in controlling gearbox meshing noise, and is of great significance in reducing noise pollution and improving the working environment of the gearbox.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140751342","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}
Pub Date : 2024-04-02DOI: 10.3389/fmech.2024.1367690
Yuhui Kang, Rongshang Chen
In the era of intelligence and automation, robots play a significant role in the field of automated welding, enhancing efficiency and precision. However, challenges persist in scenarios demanding complexity and higher precision, such as low welding planning efficiency and inaccurate weld seam defect detection. Therefore, based on digital twin technology and kernel correlation filtering algorithm, a welding tracking model is proposed. Firstly, the kernel correlation filtering algorithm is used to train the filter on the first frame of the collected image, determine the position of image features in the region, extract histogram features of image blocks, and then train the filter using ridge regression to achieve welding trajectory tracking. Additionally, an intelligent weld seam detection model is introduced, employing a backbone feature network for feature extraction, feature fusion through a feature pyramid, and quality detection of weld seams through head classification. During testing of the tracking model, the maximum tracking error is −0.232 mm, with an average absolute tracking error of 0.08 mm, outperforming other models. Comparatively, in tracking accuracy, the proposed model exhibits the fastest convergence with a precision rate of 0.845, surpassing other models. In weld seam detection, the proposed model excels with a detection accuracy of 97.35% and minimal performance loss at 0.023. In weld seam quality and melt depth error detection, the proposed model achieves errors within the range of −0.06 mm, outperforming the other two models. These results highlight the outstanding detection capabilities of the proposed model. The research findings will serve as technical references for the development of automated welding robots and welding quality inspection.
{"title":"Welding robot automation technology based on digital twin","authors":"Yuhui Kang, Rongshang Chen","doi":"10.3389/fmech.2024.1367690","DOIUrl":"https://doi.org/10.3389/fmech.2024.1367690","url":null,"abstract":"In the era of intelligence and automation, robots play a significant role in the field of automated welding, enhancing efficiency and precision. However, challenges persist in scenarios demanding complexity and higher precision, such as low welding planning efficiency and inaccurate weld seam defect detection. Therefore, based on digital twin technology and kernel correlation filtering algorithm, a welding tracking model is proposed. Firstly, the kernel correlation filtering algorithm is used to train the filter on the first frame of the collected image, determine the position of image features in the region, extract histogram features of image blocks, and then train the filter using ridge regression to achieve welding trajectory tracking. Additionally, an intelligent weld seam detection model is introduced, employing a backbone feature network for feature extraction, feature fusion through a feature pyramid, and quality detection of weld seams through head classification. During testing of the tracking model, the maximum tracking error is −0.232 mm, with an average absolute tracking error of 0.08 mm, outperforming other models. Comparatively, in tracking accuracy, the proposed model exhibits the fastest convergence with a precision rate of 0.845, surpassing other models. In weld seam detection, the proposed model excels with a detection accuracy of 97.35% and minimal performance loss at 0.023. In weld seam quality and melt depth error detection, the proposed model achieves errors within the range of −0.06 mm, outperforming the other two models. These results highlight the outstanding detection capabilities of the proposed model. The research findings will serve as technical references for the development of automated welding robots and welding quality inspection.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140752571","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}
Pub Date : 2024-03-25DOI: 10.3389/fmech.2024.1378166
Hongyu Jin
Introduction: As an important part of ship manufacturing, parts are of great significance in the calculation of its reliability level.Methods: To achieve rapid damage detection of ship parts, a method for measuring the reliability level of ship casting and forging parts based on spectral subtraction and vibration-acoustic principles was proposed. This method improves the spectral subtraction method by adding a percussion vibration signal and time-frequency analysis, and uses the principle of resonance acoustics to complete the construction of the test platform to obtain the natural frequency of the part and achieve non-destructive testing of the part.Results: The results show that using the Fabric data set as the task data set for experiments, the accuracy of the research method is 98.54%; the uncertainty is 5.58; the sensitivity detection is 0.26 μm. In the comparison of the spectrogram of the sound signal after noise reduction, this method has fewer yellow spots remaining on the spectrogram of the noise reduction sound signal, and almost no excess noise remains. In the comparison of modal simulation data of ship parts, the maximum relative error between the simulation data obtained by this method and the natural frequency value obtained from the experimental data is 2.3%, and there is no value exceeding 2.5%, so the error is small.Discussion: The above results show that this method can obtain more accurate natural frequencies of parts, can effectively calculate the reliability level of ship casting and forging parts, and provides a new method reference for the safe operation of ships.
{"title":"Detection technology application based on spectral subtraction and vibro acoustic principle in the measurement of ship reliability level","authors":"Hongyu Jin","doi":"10.3389/fmech.2024.1378166","DOIUrl":"https://doi.org/10.3389/fmech.2024.1378166","url":null,"abstract":"Introduction: As an important part of ship manufacturing, parts are of great significance in the calculation of its reliability level.Methods: To achieve rapid damage detection of ship parts, a method for measuring the reliability level of ship casting and forging parts based on spectral subtraction and vibration-acoustic principles was proposed. This method improves the spectral subtraction method by adding a percussion vibration signal and time-frequency analysis, and uses the principle of resonance acoustics to complete the construction of the test platform to obtain the natural frequency of the part and achieve non-destructive testing of the part.Results: The results show that using the Fabric data set as the task data set for experiments, the accuracy of the research method is 98.54%; the uncertainty is 5.58; the sensitivity detection is 0.26 μm. In the comparison of the spectrogram of the sound signal after noise reduction, this method has fewer yellow spots remaining on the spectrogram of the noise reduction sound signal, and almost no excess noise remains. In the comparison of modal simulation data of ship parts, the maximum relative error between the simulation data obtained by this method and the natural frequency value obtained from the experimental data is 2.3%, and there is no value exceeding 2.5%, so the error is small.Discussion: The above results show that this method can obtain more accurate natural frequencies of parts, can effectively calculate the reliability level of ship casting and forging parts, and provides a new method reference for the safe operation of ships.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140384735","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}
Pub Date : 2024-03-19DOI: 10.3389/fmech.2024.1360743
Afrah Faadhila, Mohamad Taufiqurrakhman, Puspita A. Katili, Siti Fauziyah Rahman, Delly Chipta Lestari, Y. Whulanza
Polyether–ether–ketone (PEEK) is a commonly employed biomaterial for spinal, cranial, and dental implant applications due to its mechanical properties, bio-stability, and radiolucency, especially when compared to metal alloys. However, its biologically inert behavior poses a substantial challenge in osseointegration between host bone and PEEK implants, resulting in implant loosening. Previous studies identified PEEK surface modification methods that prove beneficial in enhancing implant stability and supporting cell growth, but simultaneously, those modifications have the potential to promote bacterial attachment. In this study, sandblasting and sputter coating are performed to address the aforementioned issues as preclinical work. The aim is to investigate the effects of surface roughness through alumina sandblasting and a platinum (Pt) sputtered coating on the surface friction, cell viability, and bacterial adhesion rates of PEEK material. This study reveals that a higher average surface roughness of the PEEK sample (the highest was 1.2 μm obtained after sandblasting) increases the coefficient of friction, which was 0.25 compared to the untreated PEEK of 0.14, indicating better stability performance but also increased bacterial adhesion. A novelty of this study is that the method of Pt coating after alumina sandblasting is seen to significantly reduce the bacterial adhesion by 67% when compared to the sandblasted PEEK sample after 24 h immersion, implying better biocompatibility without changing the cell viability performance.
{"title":"Optimizing PEEK implant surfaces for improved stability and biocompatibility through sandblasting and the platinum coating approach","authors":"Afrah Faadhila, Mohamad Taufiqurrakhman, Puspita A. Katili, Siti Fauziyah Rahman, Delly Chipta Lestari, Y. Whulanza","doi":"10.3389/fmech.2024.1360743","DOIUrl":"https://doi.org/10.3389/fmech.2024.1360743","url":null,"abstract":"Polyether–ether–ketone (PEEK) is a commonly employed biomaterial for spinal, cranial, and dental implant applications due to its mechanical properties, bio-stability, and radiolucency, especially when compared to metal alloys. However, its biologically inert behavior poses a substantial challenge in osseointegration between host bone and PEEK implants, resulting in implant loosening. Previous studies identified PEEK surface modification methods that prove beneficial in enhancing implant stability and supporting cell growth, but simultaneously, those modifications have the potential to promote bacterial attachment. In this study, sandblasting and sputter coating are performed to address the aforementioned issues as preclinical work. The aim is to investigate the effects of surface roughness through alumina sandblasting and a platinum (Pt) sputtered coating on the surface friction, cell viability, and bacterial adhesion rates of PEEK material. This study reveals that a higher average surface roughness of the PEEK sample (the highest was 1.2 μm obtained after sandblasting) increases the coefficient of friction, which was 0.25 compared to the untreated PEEK of 0.14, indicating better stability performance but also increased bacterial adhesion. A novelty of this study is that the method of Pt coating after alumina sandblasting is seen to significantly reduce the bacterial adhesion by 67% when compared to the sandblasted PEEK sample after 24 h immersion, implying better biocompatibility without changing the cell viability performance.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140229663","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}
Pub Date : 2024-03-15DOI: 10.3389/fmech.2024.1371479
S. Shahrokhi, M. Taeibi Rahni, P. Akbari
The objective of this study is to develop and simulate a double slotted morphed flap with the intention of reducing drag and enhancing lift, thereby leading to a smaller flap size and reduced weight.A flap was meticulously designed to accommodate conditions at Mach 0.2 and Reynolds numbers of 4.7×106. To conduct the simulation, ANSYS FLUENT flow solver and POINTWISE grid generator were utilized. The morphing technique employed involved adjusting both flap mean camber and flap slots, ensuring minimal flow interferences. By discretizing the flap mean camber line, various flap geometries were achieved.The findings reveal a significant enhancement in the airfoil’s aerodynamic efficiency attributed to the implementation of the new flap design. The study shows that utilizing double-slotted morphing in the NACA 4412 airfoil at a 30° flap deflection angle increased the lift coefficient by 82% compared to the un-morphed state. A comparison of lift coefficients between this research and the NACA 4412 split flap at a 60° deflection angle indicates that the double-slotted morphing in the NACA 4412 airfoil at a smaller deflection angle of 30° results in a 14% higher maximum lift coefficient.
{"title":"Aerodynamic design of a double slotted morphed flap airfoil– a numerical study","authors":"S. Shahrokhi, M. Taeibi Rahni, P. Akbari","doi":"10.3389/fmech.2024.1371479","DOIUrl":"https://doi.org/10.3389/fmech.2024.1371479","url":null,"abstract":"The objective of this study is to develop and simulate a double slotted morphed flap with the intention of reducing drag and enhancing lift, thereby leading to a smaller flap size and reduced weight.A flap was meticulously designed to accommodate conditions at Mach 0.2 and Reynolds numbers of 4.7×106. To conduct the simulation, ANSYS FLUENT flow solver and POINTWISE grid generator were utilized. The morphing technique employed involved adjusting both flap mean camber and flap slots, ensuring minimal flow interferences. By discretizing the flap mean camber line, various flap geometries were achieved.The findings reveal a significant enhancement in the airfoil’s aerodynamic efficiency attributed to the implementation of the new flap design. The study shows that utilizing double-slotted morphing in the NACA 4412 airfoil at a 30° flap deflection angle increased the lift coefficient by 82% compared to the un-morphed state. A comparison of lift coefficients between this research and the NACA 4412 split flap at a 60° deflection angle indicates that the double-slotted morphing in the NACA 4412 airfoil at a smaller deflection angle of 30° results in a 14% higher maximum lift coefficient.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140237893","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}
Pub Date : 2024-03-15DOI: 10.3389/fmech.2024.1366543
Stepán Pravda, D. Sedenka, Jan Blata, Leopold Hrabovsky
Insoluble contaminants and varnish, resulting from oil degradation byproducts and sometimes depleted additive molecules, are initiated primarily due to thermal stress on the oil. This poses significant challenges in tribology, particularly for the lubrication systems of modern complex machinery, leading to severe debilitating effects such as loss of operating clearances and impaired heat transfer. Addressing varnish buildup is crucial, and timely oil analysis emerges as a valuable tool, offering essential insights into the oil degradation level and the potential presence of insoluble contaminants. Among the various laboratory testing methods available to assess varnish potential, colorimetric analysis, specifically Membrane Patch Colorimetry (MPC), is widely applied owing to its efficiency and cost-effectiveness. This study extends the application of MPC test principles, commonly utilized for turbine oils, to measure insoluble contaminants generated by degraded hydraulic fluids. Adhering to the ASTM D7843-21 standard, which stipulates the precision of this testing method for turbine oils is contingent upon the sample’s incubation period, our investigation focuses on exploring modifications to the standard 72-hour incubation period. We aim to assess the viability of shortening or extending this duration for conducting MPC tests on used hydraulic fluids, thereby potentially enhancing the precision and relevance of MPC tests in hydraulic fluid analysis.
{"title":"Influence of incubation period on membrane patch color for insoluble contaminant measurement in degraded hydraulic oils","authors":"Stepán Pravda, D. Sedenka, Jan Blata, Leopold Hrabovsky","doi":"10.3389/fmech.2024.1366543","DOIUrl":"https://doi.org/10.3389/fmech.2024.1366543","url":null,"abstract":"Insoluble contaminants and varnish, resulting from oil degradation byproducts and sometimes depleted additive molecules, are initiated primarily due to thermal stress on the oil. This poses significant challenges in tribology, particularly for the lubrication systems of modern complex machinery, leading to severe debilitating effects such as loss of operating clearances and impaired heat transfer. Addressing varnish buildup is crucial, and timely oil analysis emerges as a valuable tool, offering essential insights into the oil degradation level and the potential presence of insoluble contaminants. Among the various laboratory testing methods available to assess varnish potential, colorimetric analysis, specifically Membrane Patch Colorimetry (MPC), is widely applied owing to its efficiency and cost-effectiveness. This study extends the application of MPC test principles, commonly utilized for turbine oils, to measure insoluble contaminants generated by degraded hydraulic fluids. Adhering to the ASTM D7843-21 standard, which stipulates the precision of this testing method for turbine oils is contingent upon the sample’s incubation period, our investigation focuses on exploring modifications to the standard 72-hour incubation period. We aim to assess the viability of shortening or extending this duration for conducting MPC tests on used hydraulic fluids, thereby potentially enhancing the precision and relevance of MPC tests in hydraulic fluid analysis.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140239143","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}
Pub Date : 2024-03-13DOI: 10.3389/fmech.2024.1355711
A. Shams Taleghani, Arsalan Ghajar
The main objective of this study is to investigate the impact of ground effects on the aerodynamic coefficients of a delta wing aircraft model. Since the flow on the delta wing exhibits vortical flow inherently, it is crucial to examine the influence of ground effects under these conditions. An experimental study was conducted to enhance understanding of the aerodynamic behavior of an aircraft model incorporating a delta wing-body-vertical tail. Experiments were conducted in a subsonic wind tunnel with a test section measuring 2.8 m × 2.2 m. Measurements were taken using a sting type balance to determine the aerodynamic forces and moments. All experimental tests were performed at a Reynolds number of 1.5 × 106, with the specific aim of examining and identifying the influence of the ground on aerodynamic coefficients. To investigate how ground effect affects the aerodynamic performance of the model, a fixed plate with an adjustable height was placed underneath it. The distance between the model and the ground was varied, and resulting data indicated that increased proximity to the ground improved longitudinal static stability. The results revealed that the presence of the ground plane resulted in a 6% increase in the maximum lift coefficient. Meanwhile, the lift increases around 25% due to ground effects at an angle of attack of 14° as it approaches the ground. The lift coefficient was enhanced across all angles of attack, while the induced drag coefficient decreased, resulting in an overall increase in aerodynamic efficiency. The lift curve slope saw a 16.9% increase when the model’s height from the ground plane was less than half of the wing span. As the height decreased further, the aerodynamic center shifted backward, leading to an increase in longitudinal static stability. The rolling moment and yawing moment coefficients becomes unstable at angles of attack above 30°.
{"title":"Aerodynamic characteristics of a delta wing aircraft under ground effect","authors":"A. Shams Taleghani, Arsalan Ghajar","doi":"10.3389/fmech.2024.1355711","DOIUrl":"https://doi.org/10.3389/fmech.2024.1355711","url":null,"abstract":"The main objective of this study is to investigate the impact of ground effects on the aerodynamic coefficients of a delta wing aircraft model. Since the flow on the delta wing exhibits vortical flow inherently, it is crucial to examine the influence of ground effects under these conditions. An experimental study was conducted to enhance understanding of the aerodynamic behavior of an aircraft model incorporating a delta wing-body-vertical tail. Experiments were conducted in a subsonic wind tunnel with a test section measuring 2.8 m × 2.2 m. Measurements were taken using a sting type balance to determine the aerodynamic forces and moments. All experimental tests were performed at a Reynolds number of 1.5 × 106, with the specific aim of examining and identifying the influence of the ground on aerodynamic coefficients. To investigate how ground effect affects the aerodynamic performance of the model, a fixed plate with an adjustable height was placed underneath it. The distance between the model and the ground was varied, and resulting data indicated that increased proximity to the ground improved longitudinal static stability. The results revealed that the presence of the ground plane resulted in a 6% increase in the maximum lift coefficient. Meanwhile, the lift increases around 25% due to ground effects at an angle of attack of 14° as it approaches the ground. The lift coefficient was enhanced across all angles of attack, while the induced drag coefficient decreased, resulting in an overall increase in aerodynamic efficiency. The lift curve slope saw a 16.9% increase when the model’s height from the ground plane was less than half of the wing span. As the height decreased further, the aerodynamic center shifted backward, leading to an increase in longitudinal static stability. The rolling moment and yawing moment coefficients becomes unstable at angles of attack above 30°.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140245957","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}
Pub Date : 2024-03-11DOI: 10.3389/fmech.2024.1325623
M. Jiménez-Xamán, M. Hernández-Hernández, Rasikh Tariq, Saulo Landa-Damas, M. Rodríguez-Vázquez, A. Aranda-Arizmendi, P. Cruz-Alcantar
The dominant phenomenon in laser welding processes is heat transfer by conduction, making it crucial to gain insights into energy distribution within the heat-affected region, including the melt pool. Thermal analysis enables the description of thermo-mechanical, metallurgical aspects, and also addresses studies related to fluid flow and energy transfer. As research in welding processes has advanced, these models have evolved. This is why it is now efficient to use computational modeling techniques as it allows us to analyze the behavior of laser welding during the process. This underlines the importance of this work which has carried out an exhaustive theoretical literature review with the objective of classifying and describing the numerical simulations of laser welding based on the physics involved. In that sense, the mathematical models and strategies used in laser welding are explored in a general way. Therefore, two types of laser welding by conduction and deep penetration are defined from this point and they are categorized according to the phenomena involved in Model Heat Conduction and Model Integral Multiphysics. This comprehensive review article serves as a valuable resource for higher education students by providing a structured and detailed exploration of laser welding and its mathematical modeling. By classifying and describing numerical simulations based on the physics involved, it offers a framework for students to understand the complexities of this field. Additionally, this innovative approach to organizing and presenting research contributes to educational innovation by facilitating a more efficient and effective learning experience, helping students acquire the knowledge and research skills necessary for advancements in the laser welding domain.
{"title":"Numerical simulations and mathematical models in laser welding: a review based on physics and heat source models","authors":"M. Jiménez-Xamán, M. Hernández-Hernández, Rasikh Tariq, Saulo Landa-Damas, M. Rodríguez-Vázquez, A. Aranda-Arizmendi, P. Cruz-Alcantar","doi":"10.3389/fmech.2024.1325623","DOIUrl":"https://doi.org/10.3389/fmech.2024.1325623","url":null,"abstract":"The dominant phenomenon in laser welding processes is heat transfer by conduction, making it crucial to gain insights into energy distribution within the heat-affected region, including the melt pool. Thermal analysis enables the description of thermo-mechanical, metallurgical aspects, and also addresses studies related to fluid flow and energy transfer. As research in welding processes has advanced, these models have evolved. This is why it is now efficient to use computational modeling techniques as it allows us to analyze the behavior of laser welding during the process. This underlines the importance of this work which has carried out an exhaustive theoretical literature review with the objective of classifying and describing the numerical simulations of laser welding based on the physics involved. In that sense, the mathematical models and strategies used in laser welding are explored in a general way. Therefore, two types of laser welding by conduction and deep penetration are defined from this point and they are categorized according to the phenomena involved in Model Heat Conduction and Model Integral Multiphysics. This comprehensive review article serves as a valuable resource for higher education students by providing a structured and detailed exploration of laser welding and its mathematical modeling. By classifying and describing numerical simulations based on the physics involved, it offers a framework for students to understand the complexities of this field. Additionally, this innovative approach to organizing and presenting research contributes to educational innovation by facilitating a more efficient and effective learning experience, helping students acquire the knowledge and research skills necessary for advancements in the laser welding domain.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140252201","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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