Pub Date : 2023-08-28DOI: 10.3389/fmech.2023.1156721
Ole-Martin Grindheim, Y. Xing, T. Impelluso
This research applies the moving frame method (MFM) to the multi-body dynamic analysis of an OC3 phase IV spar buoy with the NREL 5MW turbine. Further, it verifies previous results obtained through numerical comparisons with commercial software. The long-term goal is to lay the foundation for leveraging the MFM to create a self-contained software system for future analyses that can incorporate effects that are more sophisticated, when commercial codes fall short. In this first evidentiary phase, this project treats the floating turbine as a three-bodied system consisting of the platform (platform + tower), nacelle and rotor (hub + blades). Then the paper presents the MFM in a tutorial style—in the context of this problem’s resolution. The paper supplements the multi-body dynamic equations of motion obtained through the MFM with simplified and reduced hydrodynamic, aerodynamic and mooring loads to simulate the translational and rotational response of the floating turbine under various load conditions. The results closely approximate those found in previous work and, in the process, demonstrates MFM’s analytical advantage. Current results capture the coupled responses in all degrees of freedom and gyroscopic effects occurring when the platform pitches with the spinning rotor. The project thus provides an accurate model for the dynamics of the turbine and opens the door to inserting correct advanced hydrodynamics to validate the model further. The work presents simulations for the different load cases through a 3D web page using WebGL and the ThreeJS library. Users may download all software to verify the results. An undergraduate student conducted the work alone, demonstrating the ease of implementation of the MFM.
{"title":"Dynamic analysis and validation of a multi-body floating wind turbine using the moving frame method","authors":"Ole-Martin Grindheim, Y. Xing, T. Impelluso","doi":"10.3389/fmech.2023.1156721","DOIUrl":"https://doi.org/10.3389/fmech.2023.1156721","url":null,"abstract":"This research applies the moving frame method (MFM) to the multi-body dynamic analysis of an OC3 phase IV spar buoy with the NREL 5MW turbine. Further, it verifies previous results obtained through numerical comparisons with commercial software. The long-term goal is to lay the foundation for leveraging the MFM to create a self-contained software system for future analyses that can incorporate effects that are more sophisticated, when commercial codes fall short. In this first evidentiary phase, this project treats the floating turbine as a three-bodied system consisting of the platform (platform + tower), nacelle and rotor (hub + blades). Then the paper presents the MFM in a tutorial style—in the context of this problem’s resolution. The paper supplements the multi-body dynamic equations of motion obtained through the MFM with simplified and reduced hydrodynamic, aerodynamic and mooring loads to simulate the translational and rotational response of the floating turbine under various load conditions. The results closely approximate those found in previous work and, in the process, demonstrates MFM’s analytical advantage. Current results capture the coupled responses in all degrees of freedom and gyroscopic effects occurring when the platform pitches with the spinning rotor. The project thus provides an accurate model for the dynamics of the turbine and opens the door to inserting correct advanced hydrodynamics to validate the model further. The work presents simulations for the different load cases through a 3D web page using WebGL and the ThreeJS library. Users may download all software to verify the results. An undergraduate student conducted the work alone, demonstrating the ease of implementation of the MFM.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"68 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73553003","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 : 2023-08-17DOI: 10.3389/fmech.2023.1228466
Osama Haggag, M. Demir, Sabri Cetin, W. Worek, Jeffrey Premer, D. Pandelidis
Increasing the energy efficiency of cooling in buildings is an important component of the management of global energy consumption. A super-efficient cooling system based on the evaporation concept has been developed, and initial simulation results using the MATLAB/Simulink software tool have already been published by our team. In this paper, we present the results of hardware-in-the-loop (HIL) testing of the real-time controller for the cooler. HIL testing is an engineering process in which the actual controller hardware and software are implemented and interfaced with a real-time simulated model of the controlled system. Using HIL testing, many real-world problems can be fixed before testing on the actual prototype. The controller design is implemented on a small-footprint industrial PC with CODESYS RTE and application code, while control software is implemented using IEC 61131-3 programming languages. Similarly, a real-time thermodynamic and input–output variable-based model of the room, environment, and cooler and its mechanical components (sensors and actuators) are modeled using another industrial PC with the same software tools. HIL test results show very good agreement with the offline simulations.
{"title":"Hardware-in-the-loop testing of control of a precooled desiccant air-cooling system","authors":"Osama Haggag, M. Demir, Sabri Cetin, W. Worek, Jeffrey Premer, D. Pandelidis","doi":"10.3389/fmech.2023.1228466","DOIUrl":"https://doi.org/10.3389/fmech.2023.1228466","url":null,"abstract":"Increasing the energy efficiency of cooling in buildings is an important component of the management of global energy consumption. A super-efficient cooling system based on the evaporation concept has been developed, and initial simulation results using the MATLAB/Simulink software tool have already been published by our team. In this paper, we present the results of hardware-in-the-loop (HIL) testing of the real-time controller for the cooler. HIL testing is an engineering process in which the actual controller hardware and software are implemented and interfaced with a real-time simulated model of the controlled system. Using HIL testing, many real-world problems can be fixed before testing on the actual prototype. The controller design is implemented on a small-footprint industrial PC with CODESYS RTE and application code, while control software is implemented using IEC 61131-3 programming languages. Similarly, a real-time thermodynamic and input–output variable-based model of the room, environment, and cooler and its mechanical components (sensors and actuators) are modeled using another industrial PC with the same software tools. HIL test results show very good agreement with the offline simulations.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"54 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90036428","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 : 2023-08-09DOI: 10.3389/fmech.2023.1216927
N. Y. Bykov, Y. Gorbachev, S. Fyodorov
A highly underexpanded jet outflow into the background in transition and scattering regimes is studied computationally. The direct simulation Monte Carlo method and Navier–Stokes equations are used. The main parameters’ impact on the jet flow is analyzed. It is shown that a drastic flow structure transformation occurs in a relatively narrow Reynolds numbers’ range, 5 ≤ ReL ≤ 30, featuring the jet–surrounding gas interaction. At ReL = 5, a shock wave structure that is typical for the underexpanded jet degenerates completely. The existing empirical expressions application for the estimation of the characteristic dimensions of the shock wave structure in the transition regime leads to significant inaccuracy. For the considered parameters’ range, the approaches based on the direct simulation Monte Carlo method and Navier–Stokes (NS) equations’ solution lead to similar results in the nozzle region, where the flow regime is hydrodynamic. Nevertheless, the NS approach employment for the assessment of flow parameters within rarefied shock layers is debatable.
{"title":"Highly underexpanded rarefied jet flows","authors":"N. Y. Bykov, Y. Gorbachev, S. Fyodorov","doi":"10.3389/fmech.2023.1216927","DOIUrl":"https://doi.org/10.3389/fmech.2023.1216927","url":null,"abstract":"A highly underexpanded jet outflow into the background in transition and scattering regimes is studied computationally. The direct simulation Monte Carlo method and Navier–Stokes equations are used. The main parameters’ impact on the jet flow is analyzed. It is shown that a drastic flow structure transformation occurs in a relatively narrow Reynolds numbers’ range, 5 ≤ ReL ≤ 30, featuring the jet–surrounding gas interaction. At ReL = 5, a shock wave structure that is typical for the underexpanded jet degenerates completely. The existing empirical expressions application for the estimation of the characteristic dimensions of the shock wave structure in the transition regime leads to significant inaccuracy. For the considered parameters’ range, the approaches based on the direct simulation Monte Carlo method and Navier–Stokes (NS) equations’ solution lead to similar results in the nozzle region, where the flow regime is hydrodynamic. Nevertheless, the NS approach employment for the assessment of flow parameters within rarefied shock layers is debatable.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"9 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78495752","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 : 2023-08-08DOI: 10.3389/fmech.2023.1232562
Daniel P. da Silva, João Pinheiro, Saba Abdulghani, C. Kamma-Lorger, J. Martinez, E. Solano, A. Mateus, Paula Pascoal‐Faria, G. Mitchell
Direct digital manufacturing has been identified as one of the key tools of Industry 4.0 and it enables the creation of products directly through digital definition. Commonly known as additive manufacturing, it comprises a set of technologies that are expressively agile in small-scale productions and prototyping, in comparison to conventional mass manufacturing processes, such as injection molding of plastics. It streamlines mass customization, allows the production of highly complex objects, and has been broadly applied in several fields, from medical devices to the aerospace industry. Although a new era of design possibilities and accessibility was unveiled, most developments are focused on shape reproduction precision and the development of new feeding systems and materials. This work is focused on a shift in design for additive manufacturing, where the polymer properties, by means of the adjustment of the process conditions (extrusion rate, the write speed, and the nozzle temperature, among others), constitute a decision-making variable. In order to evaluate the morphology of semicrystalline polymers during extrusion-based 3D printing, in-situ time-resolving small and wide-angle X-ray scattering measurements were performed at the ALBA synchrotron light source in Barcelona (Spain). The goal of this research is to develop a material property mapping methodology during semicrystalline polymer melt extrusion-based 3D printing Some experiments were performed with low-density polyethylene, and we were able to confirm a correlation between the extrusion rate and writing speed of the printing with the level of preferred orientation of the chain folded lamellar crystals in the extrudate.
{"title":"Property mapping of LDPE during 3D printing: evaluating morphological development with X-ray scattering","authors":"Daniel P. da Silva, João Pinheiro, Saba Abdulghani, C. Kamma-Lorger, J. Martinez, E. Solano, A. Mateus, Paula Pascoal‐Faria, G. Mitchell","doi":"10.3389/fmech.2023.1232562","DOIUrl":"https://doi.org/10.3389/fmech.2023.1232562","url":null,"abstract":"Direct digital manufacturing has been identified as one of the key tools of Industry 4.0 and it enables the creation of products directly through digital definition. Commonly known as additive manufacturing, it comprises a set of technologies that are expressively agile in small-scale productions and prototyping, in comparison to conventional mass manufacturing processes, such as injection molding of plastics. It streamlines mass customization, allows the production of highly complex objects, and has been broadly applied in several fields, from medical devices to the aerospace industry. Although a new era of design possibilities and accessibility was unveiled, most developments are focused on shape reproduction precision and the development of new feeding systems and materials. This work is focused on a shift in design for additive manufacturing, where the polymer properties, by means of the adjustment of the process conditions (extrusion rate, the write speed, and the nozzle temperature, among others), constitute a decision-making variable. In order to evaluate the morphology of semicrystalline polymers during extrusion-based 3D printing, in-situ time-resolving small and wide-angle X-ray scattering measurements were performed at the ALBA synchrotron light source in Barcelona (Spain). The goal of this research is to develop a material property mapping methodology during semicrystalline polymer melt extrusion-based 3D printing Some experiments were performed with low-density polyethylene, and we were able to confirm a correlation between the extrusion rate and writing speed of the printing with the level of preferred orientation of the chain folded lamellar crystals in the extrudate.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"30 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77229768","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 : 2023-07-28DOI: 10.3389/fmech.2023.1185231
Natacha Elster, J. Boutillier, P. Magnan, P. Naz, R. Willinger, C. Deck
Although blast-induced Traumatic Brain Injury (bTBI) has become a signature wound of conflict, its cause is not yet fully understood. Regarding primary blast injuries, i.e., those caused by the propagation of shock waves in the body, four direct and two indirect injury mechanisms have been mainly proposed in the literature. Since numerous authors have exposed instrumented animals, Post-Mortem Human Subjects (PMHS), and head substitutes to blast conditions, the aim of this review is to classify them in terms of threat, instrumentation, and investigated mechanisms. In the first part, data are collected from 6 studies on PMHS, 1 on primates, 11 on rodents, and 6 on swine for comparison purposes. Peak amplitudes of reflected pressures, intracranial pressures and cranial strains are extracted and analyzed to establish trends. Despite the small number of comparable studies, several similarities can be highlighted. Indeed, the analyses revealed a dose-response effect for most measurements. The results also depend on the orientation of the subject (forward, backward, and sideways) for the PMHS, primates, and swine. The second goal of this review is to evaluate the behavior of substitutes developed to replace PMHS experiments. Shell strains and internal pressures are thus collected on 19 geometric and anthropomorphic substitutes to assess whether they faithfully represent a human head. The results showed that these substitutes are for the most part not properly designed and therefore cannot yet reliably replace PMHS experimental data.
{"title":"A critical review of experimental analyses performed on animals, post-mortem human subjects, and substitutes to explore primary blast-induced Traumatic Brain Injuries","authors":"Natacha Elster, J. Boutillier, P. Magnan, P. Naz, R. Willinger, C. Deck","doi":"10.3389/fmech.2023.1185231","DOIUrl":"https://doi.org/10.3389/fmech.2023.1185231","url":null,"abstract":"Although blast-induced Traumatic Brain Injury (bTBI) has become a signature wound of conflict, its cause is not yet fully understood. Regarding primary blast injuries, i.e., those caused by the propagation of shock waves in the body, four direct and two indirect injury mechanisms have been mainly proposed in the literature. Since numerous authors have exposed instrumented animals, Post-Mortem Human Subjects (PMHS), and head substitutes to blast conditions, the aim of this review is to classify them in terms of threat, instrumentation, and investigated mechanisms. In the first part, data are collected from 6 studies on PMHS, 1 on primates, 11 on rodents, and 6 on swine for comparison purposes. Peak amplitudes of reflected pressures, intracranial pressures and cranial strains are extracted and analyzed to establish trends. Despite the small number of comparable studies, several similarities can be highlighted. Indeed, the analyses revealed a dose-response effect for most measurements. The results also depend on the orientation of the subject (forward, backward, and sideways) for the PMHS, primates, and swine. The second goal of this review is to evaluate the behavior of substitutes developed to replace PMHS experiments. Shell strains and internal pressures are thus collected on 19 geometric and anthropomorphic substitutes to assess whether they faithfully represent a human head. The results showed that these substitutes are for the most part not properly designed and therefore cannot yet reliably replace PMHS experimental data.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"59 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89427095","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 : 2023-07-28DOI: 10.3389/fmech.2023.1087021
Ziheng Wu, A. E. Wilson-Heid, R. J. Griffiths, Eric S. Elton
Additive manufacturing (AM) is a revolutionary technology. One of the key AM categories, metal powder-based fusion processes, has many advantages compared to conventional methods for fabricating structural materials, such as permitting increased geometric complexity. While single material metal powder AM has advanced significantly in the past decade, multi-material AM is gradually attracting more attention owing to the recent breakthrough in multi-material feedstock delivery and the growing interest of fabricating functionally graded components. Multi-material AM offers an alternative route for applications that require location dependent material properties and high geometrical complexity. The AM community has invented several ways to achieve compositional gradients and discrete boundaries in two and three dimensions using mechanical spreading, nozzle-based, electrophotographic, and hybrid techniques. This article reviews the current state of laser powder bed fusion based multi-material AM of metals with focuses on the characteristics of the material interface as well as the properties and performance of the AM built functionally graded materials. We show the common challenges and issues related to material transitions, such as defects, segregation, phase separation, and the efficacy of some potential solutions including material and process optimizations. Additionally, this study evaluates the applicability and limitations of the existing testing standards and methods for measuring mechanical performance of functionally graded materials. Finally, we discuss mechanical testing development opportunities, which can help multi-material AM move towards higher technological maturity. In general, we find that the link between gradient microstructure and mechanical properties is not well understood or studied and suggest several mechanical tests that may better inform this knowledge gap.
{"title":"A review on experimentally observed mechanical and microstructural characteristics of interfaces in multi-material laser powder bed fusion","authors":"Ziheng Wu, A. E. Wilson-Heid, R. J. Griffiths, Eric S. Elton","doi":"10.3389/fmech.2023.1087021","DOIUrl":"https://doi.org/10.3389/fmech.2023.1087021","url":null,"abstract":"Additive manufacturing (AM) is a revolutionary technology. One of the key AM categories, metal powder-based fusion processes, has many advantages compared to conventional methods for fabricating structural materials, such as permitting increased geometric complexity. While single material metal powder AM has advanced significantly in the past decade, multi-material AM is gradually attracting more attention owing to the recent breakthrough in multi-material feedstock delivery and the growing interest of fabricating functionally graded components. Multi-material AM offers an alternative route for applications that require location dependent material properties and high geometrical complexity. The AM community has invented several ways to achieve compositional gradients and discrete boundaries in two and three dimensions using mechanical spreading, nozzle-based, electrophotographic, and hybrid techniques. This article reviews the current state of laser powder bed fusion based multi-material AM of metals with focuses on the characteristics of the material interface as well as the properties and performance of the AM built functionally graded materials. We show the common challenges and issues related to material transitions, such as defects, segregation, phase separation, and the efficacy of some potential solutions including material and process optimizations. Additionally, this study evaluates the applicability and limitations of the existing testing standards and methods for measuring mechanical performance of functionally graded materials. Finally, we discuss mechanical testing development opportunities, which can help multi-material AM move towards higher technological maturity. In general, we find that the link between gradient microstructure and mechanical properties is not well understood or studied and suggest several mechanical tests that may better inform this knowledge gap.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"84 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89158244","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 : 2023-07-24DOI: 10.3389/fmech.2023.1217645
R. Groll, T. Frieler
Introduction: In the present work, an inflow model for the DSMC method is presented and validated. The approach is based on inflow mass flow rate and temperature and is particularly suitable for arbitrary nozzle flow cases with higher density, subsonic inflow conditions.Methods: The validation is performed on a nozzle test case and the results are compared with experimental and numerical results based on DSMC and Navier-Stokes methods. Calculation of inflow and outflow boundary conditions on an analytical and numerical basis is presented.Results: Results for axial and radial density, temperature, and pressure are in good agreement and reasonable relationships are obtained.Discussion: Since only the inflow mass flow rate and temperature and the vacuum background pressure need to be known to apply the model, the calculation of the inflow velocity from analytical theory can be omitted, potentially eliminating possible sources of error resulting from theorybased calculations.
{"title":"Validation of DSMC mass flow modeling for transsonic gas flows in micro-propulsion systems","authors":"R. Groll, T. Frieler","doi":"10.3389/fmech.2023.1217645","DOIUrl":"https://doi.org/10.3389/fmech.2023.1217645","url":null,"abstract":"Introduction: In the present work, an inflow model for the DSMC method is presented and validated. The approach is based on inflow mass flow rate and temperature and is particularly suitable for arbitrary nozzle flow cases with higher density, subsonic inflow conditions.Methods: The validation is performed on a nozzle test case and the results are compared with experimental and numerical results based on DSMC and Navier-Stokes methods. Calculation of inflow and outflow boundary conditions on an analytical and numerical basis is presented.Results: Results for axial and radial density, temperature, and pressure are in good agreement and reasonable relationships are obtained.Discussion: Since only the inflow mass flow rate and temperature and the vacuum background pressure need to be known to apply the model, the calculation of the inflow velocity from analytical theory can be omitted, potentially eliminating possible sources of error resulting from theorybased calculations.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"49 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80759370","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 : 2023-07-19DOI: 10.3389/fmech.2023.1163293
G. Costa, N. Sepehri
Hydraulic accumulators have long been used in hydraulic circuits. Applications vary from keeping the pressure within a circuit branch to saving load energy. Among these applications, storing and releasing energy has gained attention in recent years due to the need for efficient circuits. In this sense, accumulators are the hydraulic counterparts of batteries and capacitors in electrical circuits. From hydraulic hybrid vehicles to complex agricultural machinery, accumulators have been successfully implemented, and significant energetic gains have been reported. This article reviews typical applications where accumulators can be used to this end and discusses the challenges that still have to be overcome in each situation.
{"title":"Hydraulic accumulators in energy efficient circuits","authors":"G. Costa, N. Sepehri","doi":"10.3389/fmech.2023.1163293","DOIUrl":"https://doi.org/10.3389/fmech.2023.1163293","url":null,"abstract":"Hydraulic accumulators have long been used in hydraulic circuits. Applications vary from keeping the pressure within a circuit branch to saving load energy. Among these applications, storing and releasing energy has gained attention in recent years due to the need for efficient circuits. In this sense, accumulators are the hydraulic counterparts of batteries and capacitors in electrical circuits. From hydraulic hybrid vehicles to complex agricultural machinery, accumulators have been successfully implemented, and significant energetic gains have been reported. This article reviews typical applications where accumulators can be used to this end and discusses the challenges that still have to be overcome in each situation.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"5 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79319269","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 : 2023-07-18DOI: 10.3389/fmech.2023.1232643
Ayedh Eid Alajmi, Talal Alsaeed, J. Alotaibi, Jayanth Kumar Srelam, B. Yousif
Bonding synthetic fibres to metals to improve strength, durability, and corrosion resistance is a prevalent practise in the automotive, marine, and aerospace industries. Lap shear adhesion, a measurement of the bonding strength between composites and metallic substrates, is essential for structural integrity. The emergence of natural fibre composites as sustainable alternatives to synthetic composites makes it essential to investigate their lap shear behaviour and the effect of fibre volume fraction on composite properties. This research investigates the adhesion behaviour of coir and glass fibre epoxy composites to mild steel. Coir fibres, which are known for their resilience and tenacity, were treated with an alkaline solution to improve their adhesion to the resin. Samples of lap shear adhesion were prepared in accordance with ASTM specifications, and tests were conducted using a tensile machine. Increasing the volume fraction of coir or glass fibres decreased the bond strength, as demonstrated by the results. Due to the fibres’ greater tensile strength and rigidity, glass fibre composites exhibited superior strength. However, under tensile loading conditions, coir fibres exhibited superior adhesion to mild steel surfaces. SEM micrographs confirmed that coir composites exhibit shear failure while glass composites exhibit fibre pull-out behaviour. This study concludes by highlighting the engineering potential of coir fibres, considering their natural properties and cost-effectiveness. It is necessary to further optimise the fiber-matrix interface and comprehend the mechanical behaviour of coir composites in order to maximise their effectiveness. To assure the long-term durability of composite-metal joints, surface preparation, adhesive type, application procedure, and environmental conditions must also be considered. At a content percentage of 10%, glass fibres exhibited 100% higher shear strength compared to coir fibres in epoxy composites. Conversely, coir fibres at 10% content demonstrated approximately 75% greater shear strength than the values obtained with 40% glass fibres. The failure mechanisms observed are delamination or fibre fracture in the bonding area under tensile and shear loading. Increasing the fibre volume fraction reduces bond strength. Factors such as limited space for the matrix, tension concentrations, and the mechanical properties of the fibres contribute to weakened bonds. Glass fibres have better strength and rigidity than coir fibres, affecting load transfer and adhesion. Interfacial bonding is crucial, and maintaining it becomes more difficult with higher fibre volume fractions, resulting in weakened bonds.
{"title":"Investigating the lap shear adhesion of coir and glass-fibre reinforced epoxy bonding to mild steel with varying volume fractions","authors":"Ayedh Eid Alajmi, Talal Alsaeed, J. Alotaibi, Jayanth Kumar Srelam, B. Yousif","doi":"10.3389/fmech.2023.1232643","DOIUrl":"https://doi.org/10.3389/fmech.2023.1232643","url":null,"abstract":"Bonding synthetic fibres to metals to improve strength, durability, and corrosion resistance is a prevalent practise in the automotive, marine, and aerospace industries. Lap shear adhesion, a measurement of the bonding strength between composites and metallic substrates, is essential for structural integrity. The emergence of natural fibre composites as sustainable alternatives to synthetic composites makes it essential to investigate their lap shear behaviour and the effect of fibre volume fraction on composite properties. This research investigates the adhesion behaviour of coir and glass fibre epoxy composites to mild steel. Coir fibres, which are known for their resilience and tenacity, were treated with an alkaline solution to improve their adhesion to the resin. Samples of lap shear adhesion were prepared in accordance with ASTM specifications, and tests were conducted using a tensile machine. Increasing the volume fraction of coir or glass fibres decreased the bond strength, as demonstrated by the results. Due to the fibres’ greater tensile strength and rigidity, glass fibre composites exhibited superior strength. However, under tensile loading conditions, coir fibres exhibited superior adhesion to mild steel surfaces. SEM micrographs confirmed that coir composites exhibit shear failure while glass composites exhibit fibre pull-out behaviour. This study concludes by highlighting the engineering potential of coir fibres, considering their natural properties and cost-effectiveness. It is necessary to further optimise the fiber-matrix interface and comprehend the mechanical behaviour of coir composites in order to maximise their effectiveness. To assure the long-term durability of composite-metal joints, surface preparation, adhesive type, application procedure, and environmental conditions must also be considered. At a content percentage of 10%, glass fibres exhibited 100% higher shear strength compared to coir fibres in epoxy composites. Conversely, coir fibres at 10% content demonstrated approximately 75% greater shear strength than the values obtained with 40% glass fibres. The failure mechanisms observed are delamination or fibre fracture in the bonding area under tensile and shear loading. Increasing the fibre volume fraction reduces bond strength. Factors such as limited space for the matrix, tension concentrations, and the mechanical properties of the fibres contribute to weakened bonds. Glass fibres have better strength and rigidity than coir fibres, affecting load transfer and adhesion. Interfacial bonding is crucial, and maintaining it becomes more difficult with higher fibre volume fractions, resulting in weakened bonds.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"63 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76249681","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 : 2023-07-18DOI: 10.3389/fmech.2023.1207464
Patrich Ferretti, Curzio Pagliari, Andrea Montalti, A. Liverani
In wide-ranging areas, including hydraulics, biomedical, automotive, and aerospace, there is often a need to move a fluid with a constant flow rate. This is difficult to achieve with any type of pump and usually other elements are inserted to regularize the output. This study focused on the peristaltic pump because there are few studies on it and it has some interesting features, such as extreme simplicity, a small number of components, and the extreme compactness of the whole system. The first part of this study is focused on analyzing the classical geometry of the peristaltic pump to understand the origin of the discontinuity in the flow rate; the second part proposes a new geometry that mitigates the flow irregularity by more than 200%. In this way, it is possible to use it in all the sectors where a constant flow rate is required but where insulation between the fluid and the machine is required. Together with the flow study, an analysis of how the main geometric parameters affect the operation of the pump is provided, complete with explanatory graphs and tables. A prototype made through additive manufacturing technologies is also proposed.
{"title":"Design and development of a peristaltic pump for constant flow applications","authors":"Patrich Ferretti, Curzio Pagliari, Andrea Montalti, A. Liverani","doi":"10.3389/fmech.2023.1207464","DOIUrl":"https://doi.org/10.3389/fmech.2023.1207464","url":null,"abstract":"In wide-ranging areas, including hydraulics, biomedical, automotive, and aerospace, there is often a need to move a fluid with a constant flow rate. This is difficult to achieve with any type of pump and usually other elements are inserted to regularize the output. This study focused on the peristaltic pump because there are few studies on it and it has some interesting features, such as extreme simplicity, a small number of components, and the extreme compactness of the whole system. The first part of this study is focused on analyzing the classical geometry of the peristaltic pump to understand the origin of the discontinuity in the flow rate; the second part proposes a new geometry that mitigates the flow irregularity by more than 200%. In this way, it is possible to use it in all the sectors where a constant flow rate is required but where insulation between the fluid and the machine is required. Together with the flow study, an analysis of how the main geometric parameters affect the operation of the pump is provided, complete with explanatory graphs and tables. A prototype made through additive manufacturing technologies is also proposed.","PeriodicalId":53220,"journal":{"name":"Frontiers in Mechanical Engineering","volume":"38 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87065687","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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