A numerical methodology has been developed to analyze the thermo-hydrodynamic aspect of airflow occurring in solar chimney power plants (SCPP) according to some dominant parameters. The general curvilinear coordinates finite volume method (GCCFVM), which is necessary in the case of turbulent flow through complex geometries, is used in this work. The governing equations describing the steady state turbulent fluid flow are solved numerically using this technique. It is shown that the chimney tower dimensions control directly the hydrodynamic field. However, the collector dimensions control directly the thermal field and indirectly the hydrodynamic field. It is demonstrated that the solar radiation influences strongly and positively the thermo-hydrodynamic field by increasing the mass flow rate. The mass flow decreases with the increase of the ambient temperature and then the system is more efficient with low ambient temperature. Indeed, the mass flow rate increases from 0.8 kg/s up to approximately 2 kg/s when the solar radiation varies between 200 W/m2 and 1000 W/m2 for fixed ambient temperature value of 30 °C. When ambient temperature increases from 10 °C up to 50 °C, the mass flow rate decreases slightly and in a linear manner from 1.7 kg/s to 1.5 kg/s for fixed solar radiation intensity value of 600 W/m2. Contrasting to other studies, conclusion based on simplified analytical models, ambient temperature affects adversely the performance of a SCPP in decreasing the mass flow rate. This conclusion should be taken into consideration when analyzing models dedicated to the prediction of solar chimney power plant performance.
{"title":"Thermo-hydrodynamic Airflow Behavior Analysis in Solar Chimney Device","authors":"T. Chergui, A. Bouhdjar, S. Larbi, A. Boualit","doi":"10.3311/ppme.17971","DOIUrl":"https://doi.org/10.3311/ppme.17971","url":null,"abstract":"A numerical methodology has been developed to analyze the thermo-hydrodynamic aspect of airflow occurring in solar chimney power plants (SCPP) according to some dominant parameters. The general curvilinear coordinates finite volume method (GCCFVM), which is necessary in the case of turbulent flow through complex geometries, is used in this work. The governing equations describing the steady state turbulent fluid flow are solved numerically using this technique. It is shown that the chimney tower dimensions control directly the hydrodynamic field. However, the collector dimensions control directly the thermal field and indirectly the hydrodynamic field. It is demonstrated that the solar radiation influences strongly and positively the thermo-hydrodynamic field by increasing the mass flow rate. The mass flow decreases with the increase of the ambient temperature and then the system is more efficient with low ambient temperature. Indeed, the mass flow rate increases from 0.8 kg/s up to approximately 2 kg/s when the solar radiation varies between 200 W/m2 and 1000 W/m2 for fixed ambient temperature value of 30 °C. When ambient temperature increases from 10 °C up to 50 °C, the mass flow rate decreases slightly and in a linear manner from 1.7 kg/s to 1.5 kg/s for fixed solar radiation intensity value of 600 W/m2. Contrasting to other studies, conclusion based on simplified analytical models, ambient temperature affects adversely the performance of a SCPP in decreasing the mass flow rate. This conclusion should be taken into consideration when analyzing models dedicated to the prediction of solar chimney power plant performance.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"42 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86572152","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}
Billel Hamadi, M. Yallese, L. Boulanouar, A. Khellaf, A. Haddad
An experimental study has been carried out to investigate and compare the cutting tool performances represented by insert wear, surface roughness and cutting forces of an uncoated carbide (H13A) and three coated carbides GC2015 ( TiCN / Al2O3 / TiN ), GC1015 (TiN) and GC4215 ( TiCN / Al2O3 ) during the dry turning of AISI4140 steel. Turning was carried out during 5 minutes on cylindrical specimens (80 mm diameter and 400 mm cutting length) along with a depth of 0.5 mm, a feed rate of 0.08 mm/rev, and with a cutting speed of 350 m/min. The wear results show the effectiveness of both GC2015 and GC4215 cutting inserts where the flank wear rate of the monolayer insert (GC1015) reaches approximately 2 times that of the bilayer insert (GC4215) and 4-times that of the multilayer insert (GC2015), while insert H13A demonstrated the highest wear. Moreover, SEM analysis shows that abrasion, adhesion and chipping are the dominant wear mechanisms. The surface quality obtained with the coated GC2015 insert is found to be 1.38, 1.63 and 4.63 times better than those obtained with GC4215, GC1015 and H13A inserts respectively. Finally, the coated GC2015 (CVD) cutting insert is identified as the leading material in terms of cutting force as the results found show that the ratios are ( Ft-GC4215 / Ft-GC2015 ) = 1.05, ( Ft-GC1015 / Ft-GC2015 ) = 1.13 and ( Ft-H13A / Ft-GC2015 ) = 1.77.
{"title":"A Comparative Study of the Performance of Uncoated, PVD, CVD and MTCVD Coated Carbide Inserts in Dry Turning of AISI4140 Steel","authors":"Billel Hamadi, M. Yallese, L. Boulanouar, A. Khellaf, A. Haddad","doi":"10.3311/ppme.18591","DOIUrl":"https://doi.org/10.3311/ppme.18591","url":null,"abstract":"An experimental study has been carried out to investigate and compare the cutting tool performances represented by insert wear, surface roughness and cutting forces of an uncoated carbide (H13A) and three coated carbides GC2015 ( TiCN / Al2O3 / TiN ), GC1015 (TiN) and GC4215 ( TiCN / Al2O3 ) during the dry turning of AISI4140 steel. Turning was carried out during 5 minutes on cylindrical specimens (80 mm diameter and 400 mm cutting length) along with a depth of 0.5 mm, a feed rate of 0.08 mm/rev, and with a cutting speed of 350 m/min. The wear results show the effectiveness of both GC2015 and GC4215 cutting inserts where the flank wear rate of the monolayer insert (GC1015) reaches approximately 2 times that of the bilayer insert (GC4215) and 4-times that of the multilayer insert (GC2015), while insert H13A demonstrated the highest wear. Moreover, SEM analysis shows that abrasion, adhesion and chipping are the dominant wear mechanisms. The surface quality obtained with the coated GC2015 insert is found to be 1.38, 1.63 and 4.63 times better than those obtained with GC4215, GC1015 and H13A inserts respectively. Finally, the coated GC2015 (CVD) cutting insert is identified as the leading material in terms of cutting force as the results found show that the ratios are ( Ft-GC4215 / Ft-GC2015 ) = 1.05, ( Ft-GC1015 / Ft-GC2015 ) = 1.13 and ( Ft-H13A / Ft-GC2015 ) = 1.77.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"18 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81577092","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}
B. Varbai, Patrik Bolyhos, D. Kemény, K. Májlinger
In several applications duplex stainless steels should be joint welded to conventional austenitic stainless steels. In this research LDX 2101 lean duplex stainless steel sheets were welded to conventional 304 austenitic stainless steels, using gas tungsten arc welding. For the welded joints three different welding rods were used: ER 308L, ER 309LSi, and ER 2209. For gas shielding two different shielding gases were used: argon and argon +2% nitrogen. It was found that the nitrogen addition to the shielding gas promoted austenite formation in the weld metal. It was also found Schaeffler-diagram modified by Outokumpu showed a very good estimation to the ferrite content and chemical composition of the weld metal. The ferrite content estimated by the Outokumpu-diagram, showed a close correlation to measured ferrite contents, the highest error was 30%. In case of the chemical composition of the weld metal, the Cr- and Ni-contents were estimated with a maximum of 15% error. In terms of the corrosion resistance, the best pitting corrosion resistance was achieved using the 308L welding rod with argon shielding gas, where the weight loss was 1.6% after the 24 hours immersion test.
{"title":"Microstructure and Corrosion Properties of Austenitic and Duplex Stainless Steel Dissimilar Joints","authors":"B. Varbai, Patrik Bolyhos, D. Kemény, K. Májlinger","doi":"10.3311/ppme.21007","DOIUrl":"https://doi.org/10.3311/ppme.21007","url":null,"abstract":"In several applications duplex stainless steels should be joint welded to conventional austenitic stainless steels. In this research LDX 2101 lean duplex stainless steel sheets were welded to conventional 304 austenitic stainless steels, using gas tungsten arc welding. For the welded joints three different welding rods were used: ER 308L, ER 309LSi, and ER 2209. For gas shielding two different shielding gases were used: argon and argon +2% nitrogen. It was found that the nitrogen addition to the shielding gas promoted austenite formation in the weld metal. It was also found Schaeffler-diagram modified by Outokumpu showed a very good estimation to the ferrite content and chemical composition of the weld metal. The ferrite content estimated by the Outokumpu-diagram, showed a close correlation to measured ferrite contents, the highest error was 30%. In case of the chemical composition of the weld metal, the Cr- and Ni-contents were estimated with a maximum of 15% error. In terms of the corrosion resistance, the best pitting corrosion resistance was achieved using the 308L welding rod with argon shielding gas, where the weight loss was 1.6% after the 24 hours immersion test.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"42 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72799535","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}
Ibolya Tavaszi, A. Toth, T. Pilissy, M. Bauer, Zsolt Hodosán, G. Stépán, B. Magyar, G. Fazekas
The REHAROB robotic upper limb rehabilitation system was improved with a custom-designed and developed hand/finger therapy module. The new module extends the scope of the applicable motion therapy from passive to active reach-to-grasp activities of daily living tasks, and the range of treated anatomical joints was also extended to every proximal and distal upper limb anatomical joint. Finger exercising and object grasping are supported with a pair of two degree-of-freedom (DOF) robotic fingers. One of the robotic fingers moves the index/middle/ring fingers together, whereas the other robotic finger moves the thumb. A novel hypothesis was established, analyzed, and tested for setting the orientation of the robotic finger moving the thumb. The robotic thumb is not aligned with the patient's thumb; its orientation is optimized in the patient's hand reference system to maximize the efficiency in the opposite grasping task. While most concurrent systems utilize virtual objects for grasping tasks, the REHAROB system exercises five carefully selected reach-and-grasp type activities of daily living (ADL) with real objects. Actuating the human finger phalanges through custom development finger orthoses is described. An advanced feature of the hand/finger therapy module is the left-right hand side changeover by only alternating the orientation of the robotic fingers and exchanging the finger orthoses.
{"title":"Robotic Fingers in Reach-to-Grasp Tasks of Rehabilitation","authors":"Ibolya Tavaszi, A. Toth, T. Pilissy, M. Bauer, Zsolt Hodosán, G. Stépán, B. Magyar, G. Fazekas","doi":"10.3311/ppme.17484","DOIUrl":"https://doi.org/10.3311/ppme.17484","url":null,"abstract":"The REHAROB robotic upper limb rehabilitation system was improved with a custom-designed and developed hand/finger therapy module. The new module extends the scope of the applicable motion therapy from passive to active reach-to-grasp activities of daily living tasks, and the range of treated anatomical joints was also extended to every proximal and distal upper limb anatomical joint. Finger exercising and object grasping are supported with a pair of two degree-of-freedom (DOF) robotic fingers. One of the robotic fingers moves the index/middle/ring fingers together, whereas the other robotic finger moves the thumb. A novel hypothesis was established, analyzed, and tested for setting the orientation of the robotic finger moving the thumb. The robotic thumb is not aligned with the patient's thumb; its orientation is optimized in the patient's hand reference system to maximize the efficiency in the opposite grasping task. While most concurrent systems utilize virtual objects for grasping tasks, the REHAROB system exercises five carefully selected reach-and-grasp type activities of daily living (ADL) with real objects. Actuating the human finger phalanges through custom development finger orthoses is described. An advanced feature of the hand/finger therapy module is the left-right hand side changeover by only alternating the orientation of the robotic fingers and exchanging the finger orthoses.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"17 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90036599","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}
Effect of plastic deformation on the lattice misorientation in lath martensite was investigated by Electron Backscatter Diffraction (EBSD). As-quenched rod-like specimens were plastically deformed until 9000 N, 14000 N, 19000 N and 21000 N of tensile loading. Grain average misorientation maps were collected by EBSD. It was shown that the average misorientation during plastic deformation increased from 0.887 to 1.156 degrees. Results showed that the density of geometrically necessary dislocations, which caused the lattice misorientation, slightly increased during plastic deformation of lath martensite.
{"title":"Deformation Induced Lattice Misorientation in Lath Martensite","authors":"P. Szabó","doi":"10.3311/ppme.21216","DOIUrl":"https://doi.org/10.3311/ppme.21216","url":null,"abstract":"Effect of plastic deformation on the lattice misorientation in lath martensite was investigated by Electron Backscatter Diffraction (EBSD). As-quenched rod-like specimens were plastically deformed until 9000 N, 14000 N, 19000 N and 21000 N of tensile loading. Grain average misorientation maps were collected by EBSD. It was shown that the average misorientation during plastic deformation increased from 0.887 to 1.156 degrees. Results showed that the density of geometrically necessary dislocations, which caused the lattice misorientation, slightly increased during plastic deformation of lath martensite.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"25 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85811362","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}
The deviation between the designed lattice structures and the 3D-printed ones has been studied in this research. Three types of lattice structures were designed using the SpaceClaim application in the ANSYS software and then fabricated using Direct Metal Laser Sintering (DMLS) via EOS M 290 3D printer. Considering the orthopedic application, Ti6Al4V alloy of grade 23 was selected as a material for all samples of the structures. A thorough comparison was done on the volume, mass, and porosity to effectively map the possible deviations between the designed and the printed version. The shape accuracy of the 3D printing process was discussed during the study. As the complexity of the shape of the unit cell increases, the accuracy of the printing process becomes lower. Dimensional accuracy in the XY plane is higher than accuracy in the Z plane. Simple unit cell shape was proven to be more accurate in the 3D printing process.
本文研究了设计晶格结构与3d打印晶格结构之间的偏差。利用ANSYS软件中的spacecclaim应用程序设计了三种类型的点阵结构，然后通过EOS M 290 3D打印机使用直接金属激光烧结(DMLS)进行了制造。考虑到矫形应用，所有组织样品均选用23级Ti6Al4V合金作为材料。在体积、质量和孔隙度上进行了彻底的比较，以有效地绘制设计版本和印刷版本之间可能存在的偏差。在研究过程中，讨论了3D打印过程中的形状精度。随着单晶胞形状的复杂性增加，打印过程的精度会降低。XY平面的尺寸精度高于Z平面的尺寸精度。在3D打印过程中，简单的单细胞形状被证明是更准确的。
{"title":"A Study on the Shape and Dimensional Accuracy of Additively Manufactured Titanium Lattice Structures for Orthopedic Purposes","authors":"Rashwan Alkentar, T. Mankovits","doi":"10.3311/ppme.20382","DOIUrl":"https://doi.org/10.3311/ppme.20382","url":null,"abstract":"The deviation between the designed lattice structures and the 3D-printed ones has been studied in this research. Three types of lattice structures were designed using the SpaceClaim application in the ANSYS software and then fabricated using Direct Metal Laser Sintering (DMLS) via EOS M 290 3D printer. Considering the orthopedic application, Ti6Al4V alloy of grade 23 was selected as a material for all samples of the structures. A thorough comparison was done on the volume, mass, and porosity to effectively map the possible deviations between the designed and the printed version. The shape accuracy of the 3D printing process was discussed during the study. As the complexity of the shape of the unit cell increases, the accuracy of the printing process becomes lower. Dimensional accuracy in the XY plane is higher than accuracy in the Z plane. Simple unit cell shape was proven to be more accurate in the 3D printing process.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87696952","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}
We have developed a complex Thermoplastic Resin Transfer Molding procedure to create polyamide 6 composites and their multifunctional coatings in a single production cycle with low cycle time. The advantage of the new process is that it has low emission of volatile organic compounds due to the closed mold and the products can be recycled easily, decreasing the negative impact on the environment. In addition to developing the process steps and parameters, we produced samples with different curing time and fabric content of the base layer, waiting time before coating injection, surface thickness and titanium dioxide content of the surface layer. Then we analyzed the adhesion between the surface and base layers and the warpage of the complex part. SEM analysis proved that the reinforcement fabrics could be properly impregnated with the reactive thermoplastic system during the production of the base layer. Furthermore, we showed that the strength of the interlayer bonding can be improved when the base layer is properly polymerized in the first step. Using our method developed to assess warpage, we demonstrated that the warpage of the base layer can be reduced by applying the appropriate manufacturing parameters to the surface layer.
{"title":"Development and Analysis of an In-Mold Coating Procedure for Thermoplastic Resin Transfer Molding to Produce PA6 Composites with a Multifunctional Surface","authors":"O. V. Semperger, Dániel Török, A. Suplicz","doi":"10.3311/ppme.21048","DOIUrl":"https://doi.org/10.3311/ppme.21048","url":null,"abstract":"We have developed a complex Thermoplastic Resin Transfer Molding procedure to create polyamide 6 composites and their multifunctional coatings in a single production cycle with low cycle time. The advantage of the new process is that it has low emission of volatile organic compounds due to the closed mold and the products can be recycled easily, decreasing the negative impact on the environment. In addition to developing the process steps and parameters, we produced samples with different curing time and fabric content of the base layer, waiting time before coating injection, surface thickness and titanium dioxide content of the surface layer. Then we analyzed the adhesion between the surface and base layers and the warpage of the complex part. SEM analysis proved that the reinforcement fabrics could be properly impregnated with the reactive thermoplastic system during the production of the base layer. Furthermore, we showed that the strength of the interlayer bonding can be improved when the base layer is properly polymerized in the first step. Using our method developed to assess warpage, we demonstrated that the warpage of the base layer can be reduced by applying the appropriate manufacturing parameters to the surface layer.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"9 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87173903","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}
The aim of this study is to examine displacements, strains and stresses as well as to predict possible failure mechanisms arising at the yarn-matrix level of a test specimen of a railway composite cord-rubber air brake tube undergoing uniaxial tension by microscale modelling.Furthermore, this paper also aims to verify the material properties of the micromodel of the test specimen.The micromodel is based on macromodels (by matching the boundary conditions of the micromodels with displacements of the macromodels) created previously by authors of this article. The reinforcing yarns are described by an orthotropic, elastic material model, whereas the matrix has been described by a 2 parameter Mooney-Rivlin model, which all have been validated before by a uniaxial tensile test and a three-point bending test.Force-displacement curves of the micromodel and experimental results show a considerably good agreement.Yarns have a less dominant role in the load transfer mechanism of the reinforcement layers, because of the short-yarn reinforced nature of the specimen. Shear strains are high at free yarn ends marking the possible locations of failure initiation in debonding in the shear mechanism of the reinforcement layers. High shear strain values imply that the dominant mode of load transfer is shear in the matrix in the reinforcement layers.
{"title":"FE Micromodel of a Cord-rubber Composite Test Specimen Subjected to Uniaxial Tension","authors":"G. Szabó, K. Varadi","doi":"10.3311/ppme.20363","DOIUrl":"https://doi.org/10.3311/ppme.20363","url":null,"abstract":"The aim of this study is to examine displacements, strains and stresses as well as to predict possible failure mechanisms arising at the yarn-matrix level of a test specimen of a railway composite cord-rubber air brake tube undergoing uniaxial tension by microscale modelling.Furthermore, this paper also aims to verify the material properties of the micromodel of the test specimen.The micromodel is based on macromodels (by matching the boundary conditions of the micromodels with displacements of the macromodels) created previously by authors of this article. The reinforcing yarns are described by an orthotropic, elastic material model, whereas the matrix has been described by a 2 parameter Mooney-Rivlin model, which all have been validated before by a uniaxial tensile test and a three-point bending test.Force-displacement curves of the micromodel and experimental results show a considerably good agreement.Yarns have a less dominant role in the load transfer mechanism of the reinforcement layers, because of the short-yarn reinforced nature of the specimen. Shear strains are high at free yarn ends marking the possible locations of failure initiation in debonding in the shear mechanism of the reinforcement layers. High shear strain values imply that the dominant mode of load transfer is shear in the matrix in the reinforcement layers.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"19 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83393189","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}
This paper presents the Finite Element (FE) analyses carried out with the aim to predict the tooth root fatigue and Rolling Contact Fatigue (RCF) behavior of spur gears, in terms of crack propagation maximum number of cycles. The combination of different materials, i.e. steel and titanium, and surface treatments, i.e. case-hardening and application of surface layers by Physical Vapor Deposition (PVD), are investigated. The residual stresses induced by the deposition of the coating are modelled. The stress intensity is described by linear elastic relations based on the crack tip opening displacement and the crack propagation in the case-hardened spur gears is described with the help of mathematical models. Experiments are carried out to evaluate tooth damage under RCF for different treated gears. The best solutions in terms of bulk material – treatment combination among the ones investigated are identified, also highlighting innovative possibilities which can guarantee appreciable performance.
{"title":"Finite Element Analysis and Experiments for Predicting Fatigue and Rolling Contact Fatigue Behavior of Spur Gears","authors":"S. Baragetti","doi":"10.3311/ppme.18423","DOIUrl":"https://doi.org/10.3311/ppme.18423","url":null,"abstract":"This paper presents the Finite Element (FE) analyses carried out with the aim to predict the tooth root fatigue and Rolling Contact Fatigue (RCF) behavior of spur gears, in terms of crack propagation maximum number of cycles. The combination of different materials, i.e. steel and titanium, and surface treatments, i.e. case-hardening and application of surface layers by Physical Vapor Deposition (PVD), are investigated. The residual stresses induced by the deposition of the coating are modelled. The stress intensity is described by linear elastic relations based on the crack tip opening displacement and the crack propagation in the case-hardened spur gears is described with the help of mathematical models. Experiments are carried out to evaluate tooth damage under RCF for different treated gears. The best solutions in terms of bulk material – treatment combination among the ones investigated are identified, also highlighting innovative possibilities which can guarantee appreciable performance.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"24 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87302225","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}
The treatment of large acetabular bone defects is a challenging task for the clinical experts. One of the most important part is the selection or the design the most appropriate implant. The aim of the study is to explore the potential of topology optimization for the treatment of extensive pelvic bone defects. Using a finite element method, the authors investigate different design spaces and load cases. Sensitivity tests for the material characteristic of the bone and the constraint of the applied volume-fraction were performed. The results are topology-optimized acetabular cage concepts with similar designs. The conceptual designs are not sensitive to the changing of the elastic modulus of the bone and the volume-fraction constraint. The reason for the similarity between the designs is the close connections, they have a special role in maximizing the stiffness. With the use of our design space, a lot of bone grafts can be put behind the cage and it can give an idea for sheet metal conceptual designs. Due to the close connections, similar conceptual variants are generated under normal walking load, which can be used for faster calculations in similar cases.
{"title":"Effect of the Design Constraints and the Loading Model on the Geometry of Topology Optimized Acetabular Cages","authors":"Martin O. Dóczi, Róbert Sződy, P. Zwierczyk","doi":"10.3311/ppme.20238","DOIUrl":"https://doi.org/10.3311/ppme.20238","url":null,"abstract":"The treatment of large acetabular bone defects is a challenging task for the clinical experts. One of the most important part is the selection or the design the most appropriate implant. The aim of the study is to explore the potential of topology optimization for the treatment of extensive pelvic bone defects. Using a finite element method, the authors investigate different design spaces and load cases. Sensitivity tests for the material characteristic of the bone and the constraint of the applied volume-fraction were performed. The results are topology-optimized acetabular cage concepts with similar designs. The conceptual designs are not sensitive to the changing of the elastic modulus of the bone and the volume-fraction constraint. The reason for the similarity between the designs is the close connections, they have a special role in maximizing the stiffness. With the use of our design space, a lot of bone grafts can be put behind the cage and it can give an idea for sheet metal conceptual designs. Due to the close connections, similar conceptual variants are generated under normal walking load, which can be used for faster calculations in similar cases.","PeriodicalId":43630,"journal":{"name":"PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89893780","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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