Ball mills are the foremost equipment used for grinding in the mineral processing sector. Lifters are placed on the internal walls of the mill and are designed to lift the grinding media (balls) to a higher position. In the calculation of energy consumption in ball mills, classical theories mainly consider factors like the charge fill level, lifter dimensions, the number of lifters, and the rotational speed of the mill. This research recognizes the significance of lifter geometry and proposes a new lifter design aimed at optimizing the energy consumption and efficiency of ball mills. Simulation results by discrete elements obtained in this study were validated using experimental results. By conducting this comparative analysis, the aims of the study was to examine the impact of the new lifter's geometry and rotational speed of the mill on torque, power draw, particles behavior, and contact forces. The findings indicate that when the pitch of the lifters is increased, there is a reduction of 3.30% in torque and power consumption. Additionally, this change leads to an increase in the number of cataracting particles and a 6 to 7% increase in contact forces compared to lifters with a straight shape.
{"title":"Analyzing the influence of lifter design and ball mill speed on grinding performance, particle behavior and contact forces","authors":"Ali Safa, Sahraoui Aissat","doi":"10.1051/meca/2023035","DOIUrl":"https://doi.org/10.1051/meca/2023035","url":null,"abstract":"Ball mills are the foremost equipment used for grinding in the mineral processing sector. Lifters are placed on the internal walls of the mill and are designed to lift the grinding media (balls) to a higher position. In the calculation of energy consumption in ball mills, classical theories mainly consider factors like the charge fill level, lifter dimensions, the number of lifters, and the rotational speed of the mill. This research recognizes the significance of lifter geometry and proposes a new lifter design aimed at optimizing the energy consumption and efficiency of ball mills. Simulation results by discrete elements obtained in this study were validated using experimental results. By conducting this comparative analysis, the aims of the study was to examine the impact of the new lifter's geometry and rotational speed of the mill on torque, power draw, particles behavior, and contact forces. The findings indicate that when the pitch of the lifters is increased, there is a reduction of 3.30% in torque and power consumption. Additionally, this change leads to an increase in the number of cataracting particles and a 6 to 7% increase in contact forces compared to lifters with a straight shape.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135312107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The shape optimization design of the developable surface is an important research topic in CAD/CAM, and it is widely used in engineering manufacturing. In this paper, NSGA-II (the elitist non-dominated sorting genetic algorithm) is used to study the multi-objective shape optimization problem of generalized cubic developable Bézier-like surfaces (GCDBLS, for short) to promote the application of GCDBLS in industrial software and engineering design. Firstly, the shape optimization of developable surfaces is transformed into the shape optimization of dyadic curves based on the point-to-plane duality theory. Secondly, a multi-objective shape parameter optimization model is developed based on three surface optimality criteria (the shortest arc length, the smallest energy, and the smallest curvature change rate of the dual curve). Finally, the results of shape parameter optimization of GCDBLS obtained by NSGA-II are compared with MSSA and MOGOA to verify the feasibility and superiority of NSGA-II in solving multi-objective shape optimization problems for developable surfaces and the flexibility of GCDBLS in the construction of developable surfaces.
{"title":"Multi-objective shape optimization of developable Bézier-like surfaces using non-dominated sorting genetic algorithm","authors":"Jing Lu, XiaoBo Su, Jingyu Zhong, Gang Hu","doi":"10.1051/meca/2023031","DOIUrl":"https://doi.org/10.1051/meca/2023031","url":null,"abstract":"The shape optimization design of the developable surface is an important research topic in CAD/CAM, and it is widely used in engineering manufacturing. In this paper, NSGA-II (the elitist non-dominated sorting genetic algorithm) is used to study the multi-objective shape optimization problem of generalized cubic developable Bézier-like surfaces (GCDBLS, for short) to promote the application of GCDBLS in industrial software and engineering design. Firstly, the shape optimization of developable surfaces is transformed into the shape optimization of dyadic curves based on the point-to-plane duality theory. Secondly, a multi-objective shape parameter optimization model is developed based on three surface optimality criteria (the shortest arc length, the smallest energy, and the smallest curvature change rate of the dual curve). Finally, the results of shape parameter optimization of GCDBLS obtained by NSGA-II are compared with MSSA and MOGOA to verify the feasibility and superiority of NSGA-II in solving multi-objective shape optimization problems for developable surfaces and the flexibility of GCDBLS in the construction of developable surfaces.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135505453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The homogenized elastic properties of polycrystals depend on the grain morphology and crystallographic orientations. For simplification purposes, the orientations of the grains are usually considered three independent Euler angles. However, experimental investigations reveal spatial correlations in these angles. The Karhunen–Loève expansion is used to generate random fields of Euler angles having exponential kernel functions with varying correlation lengths. The effective elastic moduli for numerically generated statistically equiaxed cubic polycrystals are estimated via the classical Eshelby–Kröner Self-Consistent homogenization model. The influence of the correlation lengths of the orientations’ random fields on the statistical properties of the effective elastic moduli has been investigated. Our results show that spatially correlated Euler angles could increase the variability of the homogenized elastic properties compared to the ones having uncorrelated Euler angles. Nevertheless, using independent random variables for Euler angles remains valid when correlation lengths are close to the average grain size.
{"title":"Statistical properties of effective elastic moduli of random cubic polycrystals","authors":"Ningyue Sheng, Shahram Khazaie, Mathilde Chevreuil, Sylvain Fréour","doi":"10.1051/meca/2023030","DOIUrl":"https://doi.org/10.1051/meca/2023030","url":null,"abstract":"The homogenized elastic properties of polycrystals depend on the grain morphology and crystallographic orientations. For simplification purposes, the orientations of the grains are usually considered three independent Euler angles. However, experimental investigations reveal spatial correlations in these angles. The Karhunen–Loève expansion is used to generate random fields of Euler angles having exponential kernel functions with varying correlation lengths. The effective elastic moduli for numerically generated statistically equiaxed cubic polycrystals are estimated via the classical Eshelby–Kröner Self-Consistent homogenization model. The influence of the correlation lengths of the orientations’ random fields on the statistical properties of the effective elastic moduli has been investigated. Our results show that spatially correlated Euler angles could increase the variability of the homogenized elastic properties compared to the ones having uncorrelated Euler angles. Nevertheless, using independent random variables for Euler angles remains valid when correlation lengths are close to the average grain size.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135784543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Afsal Pulikkathodi, Elisabeth Lacazedieu, Ludovic Chamoin, Juan Pedro Berro Ramirez, Laurent Rota, Malek Zarroug
Solving large structural problems with multiple complex localized behaviors is extremely challenging. To address this difficulty, both intrusive and non-intrusive Domain Decomposition Methods (DDM) have been developed in the past, where the refined model (local) is solved separately in its own space and time scales. In this work, the Finite Element Method (FEM) at the local scale is replaced with a data-driven Reduced Order Model (ROM) to further decrease computational time. The reduced model aims to create a low-cost, accurate and efficient mapping from interface velocities to interface forces and enable the prediction of their time evolution. The present work proposes a modeling technique based on the Physics-Guided Architecture of Neural Networks (PGANNs), which incorporates physical variables other than input/output variables into the neural network architecture. We develop this approach on a 2D plate with a hole as well as a 3D case with spot-welded plates undergoing fast deformation, representing nonlinear elastoplasticity problems. Neural networks are trained using simulation data generated by explicit dynamic FEM solvers. The PGANN results are in good agreement with the FEM solutions for both test cases, including those in the training dataset as well as the unseen dataset, given the loading type is present in the training set.
{"title":"A neural network-based data-driven local modeling of spotwelded plates under impact","authors":"Afsal Pulikkathodi, Elisabeth Lacazedieu, Ludovic Chamoin, Juan Pedro Berro Ramirez, Laurent Rota, Malek Zarroug","doi":"10.1051/meca/2023029","DOIUrl":"https://doi.org/10.1051/meca/2023029","url":null,"abstract":"Solving large structural problems with multiple complex localized behaviors is extremely challenging. To address this difficulty, both intrusive and non-intrusive Domain Decomposition Methods (DDM) have been developed in the past, where the refined model (local) is solved separately in its own space and time scales. In this work, the Finite Element Method (FEM) at the local scale is replaced with a data-driven Reduced Order Model (ROM) to further decrease computational time. The reduced model aims to create a low-cost, accurate and efficient mapping from interface velocities to interface forces and enable the prediction of their time evolution. The present work proposes a modeling technique based on the Physics-Guided Architecture of Neural Networks (PGANNs), which incorporates physical variables other than input/output variables into the neural network architecture. We develop this approach on a 2D plate with a hole as well as a 3D case with spot-welded plates undergoing fast deformation, representing nonlinear elastoplasticity problems. Neural networks are trained using simulation data generated by explicit dynamic FEM solvers. The PGANN results are in good agreement with the FEM solutions for both test cases, including those in the training dataset as well as the unseen dataset, given the loading type is present in the training set.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135495403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stereo digital image correlation (Stereo-DIC) is recurrent in photo-mechanics to measure kinematic fields which can be of high interest for instrumenting open-mould forming processes. Nevertheless, in the presence of pre-heating operations, as observed in the context of thermoforming processes, natural convective heat flows risk emerging and causing optical distortions in the recorded images. Consequently, this alters the precision of the measured full-fields of displacements. To address these challenges, this study proposes an experimental approach with two distinctive features. Firstly, it focuses on regenerating the heat haze effect at a laboratory scale within a partially opened vertical enclosure and without utilizing any filtering air flows. Secondly, the study quantifies the spatial and temporal variations of errors through statistical analyses of the differences between measurements obtained from quasi-static speckle translations and known imposed displacements. Experimental results indicate that the main cause of displacement errors is related to the 3D nature of the hot air turbulence caused by the natural convection phenomenon. This observation is supported by the detection of feather-shaped heat flows causing optical out-of-plane surface deviations. Furthermore, the study validates the possibility of obtaining time-dependent corrective functions for bias errors, which characterize the performance of the calibrated Stereo-DIC system in the presence of heat haze. Despite the limitation of extensive measurements required by the proposed approach, this study contributes to addressing the heat haze effect and constitutes a step towards extending the use of stereo-DIC for in-situ instrumentation of short-duration thermomechanical tests in the presence of heat haze.
{"title":"Experimental quantification of heat haze errors in stereo-DIC displacements: Application to thermoplastics thermoforming temperature range","authors":"Aniket Ghosh Dastidar, Abderrahmane Ayadi, Marie-France Lacrampe","doi":"10.1051/meca/2023034","DOIUrl":"https://doi.org/10.1051/meca/2023034","url":null,"abstract":"Stereo digital image correlation (Stereo-DIC) is recurrent in photo-mechanics to measure kinematic fields which can be of high interest for instrumenting open-mould forming processes. Nevertheless, in the presence of pre-heating operations, as observed in the context of thermoforming processes, natural convective heat flows risk emerging and causing optical distortions in the recorded images. Consequently, this alters the precision of the measured full-fields of displacements. To address these challenges, this study proposes an experimental approach with two distinctive features. Firstly, it focuses on regenerating the heat haze effect at a laboratory scale within a partially opened vertical enclosure and without utilizing any filtering air flows. Secondly, the study quantifies the spatial and temporal variations of errors through statistical analyses of the differences between measurements obtained from quasi-static speckle translations and known imposed displacements. Experimental results indicate that the main cause of displacement errors is related to the 3D nature of the hot air turbulence caused by the natural convection phenomenon. This observation is supported by the detection of feather-shaped heat flows causing optical out-of-plane surface deviations. Furthermore, the study validates the possibility of obtaining time-dependent corrective functions for bias errors, which characterize the performance of the calibrated Stereo-DIC system in the presence of heat haze. Despite the limitation of extensive measurements required by the proposed approach, this study contributes to addressing the heat haze effect and constitutes a step towards extending the use of stereo-DIC for in-situ instrumentation of short-duration thermomechanical tests in the presence of heat haze.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135559776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leandro M. da Silva, Christophe Cellard, Edouard Geslain, Laurent Sohier, Olivier Ponte-Felgueiras, Romain Créac'hcadec
The automotive industry is undergoing significant changes driven by factors such as reducing carbon dioxide emissions, advancing technology, evolving regulations, and the emergence of new energy sources. Lightweight materials, particularly aluminum alloys, are being extensively researched and integrated into vehicles to reduce weight and improve performance. However, the heating process during vehicle production can cause thermal buckling in thin aluminum alloy structures, affecting their appearance and quality. While thermal buckling has been studied in other industries, research in the automotive sector, particularly for non-structural parts like car roofs, is limited. This study uses numerical simulation to predict thermal buckling and post-buckling behavior of a EN AW 6016-T4 alloy car roof assembled in a predominantly steel body-in-white. The research findings indicate that roof buckling occurs at a relatively low temperature difference of approximately 60 °C, which is lower than the maximum temperatures experienced during the painting phases in the automotive industry. Consequently, undulations in the roof's shape become apparent, underscoring the importance of design modifications to ensure visual conformity. Validation through physical testing confirms the model's accuracy, providing valuable insights for designing lightweight structures with improved performance and aesthetics.
{"title":"Numerical investigation of thermal buckling and post-buckling behavior of an EN AW 6016-T4 car roof assembled in a steel body-in-white","authors":"Leandro M. da Silva, Christophe Cellard, Edouard Geslain, Laurent Sohier, Olivier Ponte-Felgueiras, Romain Créac'hcadec","doi":"10.1051/meca/2023032","DOIUrl":"https://doi.org/10.1051/meca/2023032","url":null,"abstract":"The automotive industry is undergoing significant changes driven by factors such as reducing carbon dioxide emissions, advancing technology, evolving regulations, and the emergence of new energy sources. Lightweight materials, particularly aluminum alloys, are being extensively researched and integrated into vehicles to reduce weight and improve performance. However, the heating process during vehicle production can cause thermal buckling in thin aluminum alloy structures, affecting their appearance and quality. While thermal buckling has been studied in other industries, research in the automotive sector, particularly for non-structural parts like car roofs, is limited. This study uses numerical simulation to predict thermal buckling and post-buckling behavior of a EN AW 6016-T4 alloy car roof assembled in a predominantly steel body-in-white. The research findings indicate that roof buckling occurs at a relatively low temperature difference of approximately 60 °C, which is lower than the maximum temperatures experienced during the painting phases in the automotive industry. Consequently, undulations in the roof's shape become apparent, underscoring the importance of design modifications to ensure visual conformity. Validation through physical testing confirms the model's accuracy, providing valuable insights for designing lightweight structures with improved performance and aesthetics.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135058664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Milling with minimum quantity lubrication (MQL) is now a commonly used machining technique in industry. This paper proposed an analytical model for residual stress prediction in milling with MQL based on chip formation orthogonal cutting model and boundary lubrication effect. The effect of lubrication is considered to the change of friction coefficients and the heat loss at the flank surface, which would further affect the prediction of the cutting force and temperature. The proposed model is validated with experimental data done to AZ61A magnesium alloy and obtained a reasonable validation result. The predictive results show at the case investigated, neither feed per tooth nor depth of cut has a significant influence to the general trend of residual stress, where at the surface the residual stress is highly tensile and come to compressive at deeper depth. However, the application of MQL is shown to be able to significantly reduce the average magnitude of the residual stress.
{"title":"Analytical modeling of residual stress in end-milling with minimum quantity lubrication","authors":"Linger Cai, Yixuan Feng, S. Liang","doi":"10.1051/meca/2022002","DOIUrl":"https://doi.org/10.1051/meca/2022002","url":null,"abstract":"Milling with minimum quantity lubrication (MQL) is now a commonly used machining technique in industry. This paper proposed an analytical model for residual stress prediction in milling with MQL based on chip formation orthogonal cutting model and boundary lubrication effect. The effect of lubrication is considered to the change of friction coefficients and the heat loss at the flank surface, which would further affect the prediction of the cutting force and temperature. The proposed model is validated with experimental data done to AZ61A magnesium alloy and obtained a reasonable validation result. The predictive results show at the case investigated, neither feed per tooth nor depth of cut has a significant influence to the general trend of residual stress, where at the surface the residual stress is highly tensile and come to compressive at deeper depth. However, the application of MQL is shown to be able to significantly reduce the average magnitude of the residual stress.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89435997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on the first-order shear deformation theory, numerical methods and mechanical experiments, the shear buckling characteristics of hull plates with different holes are investigated. Through eigenvalue buckling analysis, the critical buckling stress of square plate with hole under uniform shear load on four edges was calculated. The relationship between the critical shear stress and the hole type, hole size and plate thickness was obtained by parameterization. The reduction coefficient (ki) was defined to characterize the effect of the hole on the plate, and the reduction effect of circular hole, square hole and fillet square hole was simplified by graph and fitting polynomial. The results show that the critical buckling shear stress obtained from numerical simulation is in good agreement with the experimental value. For different types of holes, the critical buckling shear stress of the square plate has the same trend with the plate thickness. Both plate thickness and hole size have great influence on the shear stability of the perforated square plate. When the hole size is constant, the critical shear stress increases with the increase of plate thickness. The smaller the hole size is, the greater the influence of plate thickness. The critical shear stress decreases with the increase of hole size, and there is a similar linear relationship. The smaller the plate thickness, the more obvious the linear relationship. In addition, based on the reduction coefficient curve or fitting polynomial proposed in this paper, the influence rules of the three different holes on the shear stability of hull plates can be obtained quickly and effectively, thus providing a useful reference for the design optimization and mechanical property evaluation of ship structures with holes.
{"title":"Shear buckling of ship plates with different holes","authors":"Zhao Zhu, Xiaowen Li, Q. Chen, Yingqiang Cai","doi":"10.1051/meca/2022004","DOIUrl":"https://doi.org/10.1051/meca/2022004","url":null,"abstract":"Based on the first-order shear deformation theory, numerical methods and mechanical experiments, the shear buckling characteristics of hull plates with different holes are investigated. Through eigenvalue buckling analysis, the critical buckling stress of square plate with hole under uniform shear load on four edges was calculated. The relationship between the critical shear stress and the hole type, hole size and plate thickness was obtained by parameterization. The reduction coefficient (ki) was defined to characterize the effect of the hole on the plate, and the reduction effect of circular hole, square hole and fillet square hole was simplified by graph and fitting polynomial. The results show that the critical buckling shear stress obtained from numerical simulation is in good agreement with the experimental value. For different types of holes, the critical buckling shear stress of the square plate has the same trend with the plate thickness. Both plate thickness and hole size have great influence on the shear stability of the perforated square plate. When the hole size is constant, the critical shear stress increases with the increase of plate thickness. The smaller the hole size is, the greater the influence of plate thickness. The critical shear stress decreases with the increase of hole size, and there is a similar linear relationship. The smaller the plate thickness, the more obvious the linear relationship. In addition, based on the reduction coefficient curve or fitting polynomial proposed in this paper, the influence rules of the three different holes on the shear stability of hull plates can be obtained quickly and effectively, thus providing a useful reference for the design optimization and mechanical property evaluation of ship structures with holes.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74605600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Albahrani, J. T. Alves, A. Duval, T. Chaise, Jean-Pierre de Vaujany, M. Guingand
A nonconventional application of worm gears exploits the irreversibility of these power transmission devices in order to realize fast emergency braking. This application can be used to secure lifting devices. A limiting factor in the design of these instantaneous braking systems is the residual deformations of the worm/wheel contacting teeth, due to the impact between them at each emergency stop. The prediction of these residual displacements requires solving of an elastic–plastic, multi-scale and multi-contact problem. Original numerical tools were developed in this study to solve the problem at global and local scales. The method has been validated by comparing the obtained results with 3D measurements on new and deformed worm/wheel pairs. In order to predict the issue of the worm gear after an impact, a criterion based on kinematic errors is proposed. Applying this criterion gives the maximal admissible torque for the braking system to be operational after the impact.
{"title":"Modelling of elastoplastic, multi-scale and multi-contact problems: application to worm gears","authors":"S. Albahrani, J. T. Alves, A. Duval, T. Chaise, Jean-Pierre de Vaujany, M. Guingand","doi":"10.1051/meca/2022003","DOIUrl":"https://doi.org/10.1051/meca/2022003","url":null,"abstract":"A nonconventional application of worm gears exploits the irreversibility of these power transmission devices in order to realize fast emergency braking. This application can be used to secure lifting devices. A limiting factor in the design of these instantaneous braking systems is the residual deformations of the worm/wheel contacting teeth, due to the impact between them at each emergency stop. The prediction of these residual displacements requires solving of an elastic–plastic, multi-scale and multi-contact problem. Original numerical tools were developed in this study to solve the problem at global and local scales. The method has been validated by comparing the obtained results with 3D measurements on new and deformed worm/wheel pairs. In order to predict the issue of the worm gear after an impact, a criterion based on kinematic errors is proposed. Applying this criterion gives the maximal admissible torque for the braking system to be operational after the impact.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73199785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nicolas Béraud, Akram Chergui, M. Limousin, F. Villeneuve, F. Vignat
Managing the quality of functional parts is a key challenge in wire arc additive manufacturing. In case of additive production of aluminum parts, porosity is one of the main limitations of this process. This paper provides an indicator of porosity through the simulation of melt pool volume in aluminum wire arc additive manufacturing. First, a review of porosity formation during WAAM process is presented. This review leads to the proposal of this article: monitoring the porosity inside produced part can be achieved through the melt pool volume monitoring. An adapted Finite Element model is then proposed to determine the evolution of the melt pool volume throughout the manufacturing process of the part. This model is validated by experimental temperature measurement. Then, in order to study the link between the porosity and the melt pool volume, two test parts are chosen to access to two different pore distributions. These two parts are simulated and produced. The porosity rates of produced parts are then measured by X-ray tomography and compared to the simulated melt pool volumes. The analysis of the results highlights the interest of the melt pool volume as a predictive indicator of the porosity rate.
{"title":"An indicator of porosity through simulation of melt pool volume in aluminum wire arc additive manufacturing","authors":"Nicolas Béraud, Akram Chergui, M. Limousin, F. Villeneuve, F. Vignat","doi":"10.1051/meca/2021052","DOIUrl":"https://doi.org/10.1051/meca/2021052","url":null,"abstract":"Managing the quality of functional parts is a key challenge in wire arc additive manufacturing. In case of additive production of aluminum parts, porosity is one of the main limitations of this process. This paper provides an indicator of porosity through the simulation of melt pool volume in aluminum wire arc additive manufacturing. First, a review of porosity formation during WAAM process is presented. This review leads to the proposal of this article: monitoring the porosity inside produced part can be achieved through the melt pool volume monitoring. An adapted Finite Element model is then proposed to determine the evolution of the melt pool volume throughout the manufacturing process of the part. This model is validated by experimental temperature measurement. Then, in order to study the link between the porosity and the melt pool volume, two test parts are chosen to access to two different pore distributions. These two parts are simulated and produced. The porosity rates of produced parts are then measured by X-ray tomography and compared to the simulated melt pool volumes. The analysis of the results highlights the interest of the melt pool volume as a predictive indicator of the porosity rate.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91015273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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