Pub Date : 2024-05-15DOI: 10.21741/9781644903131-178
Zhenyuan Qin
Abstract. Incremental sheet forming (ISF) is an advanced forming technology with high flexibility and excellent adaptability. However, conventional ISF encounters challenges in processing of hard-to-deformed materials at room temperature. To address this problem, friction stir incremental forming (FSIF) has been introduced to improve material formability at high temperatures. The aim of this work is to investigate the spindle speed effect on the forming quality for materials with different thermal conductivities by using an experimental and FE simulation. The experimental results presented the combined effect of spindle speed and conductivity on the springback and surface finish of AA1050 and CP Ti Grade 1. A good agreement was obtained in the temperature increase and distribution from experimental testing and FE simulation.
摘要增量式板材成形（ISF）是一种先进的成形技术，具有高度灵活性和出色的适应性。然而，传统的增量板材成形技术在室温下加工难变形材料时遇到了挑战。为解决这一问题，人们引入了摩擦搅拌增量成形（FSIF）技术，以改善材料在高温下的成形性。这项工作的目的是通过实验和 FE 仿真研究主轴转速对不同导热系数材料成型质量的影响。实验结果显示了主轴速度和导热系数对 AA1050 和 CP Ti Grade 1 的回弹和表面光洁度的综合影响。实验测试和 FE 仿真在温度升高和分布方面取得了良好的一致性。
{"title":"Spindle speed effect on the ISF processing of materials with different thermal conductivities","authors":"Zhenyuan Qin","doi":"10.21741/9781644903131-178","DOIUrl":"https://doi.org/10.21741/9781644903131-178","url":null,"abstract":"Abstract. Incremental sheet forming (ISF) is an advanced forming technology with high flexibility and excellent adaptability. However, conventional ISF encounters challenges in processing of hard-to-deformed materials at room temperature. To address this problem, friction stir incremental forming (FSIF) has been introduced to improve material formability at high temperatures. The aim of this work is to investigate the spindle speed effect on the forming quality for materials with different thermal conductivities by using an experimental and FE simulation. The experimental results presented the combined effect of spindle speed and conductivity on the springback and surface finish of AA1050 and CP Ti Grade 1. A good agreement was obtained in the temperature increase and distribution from experimental testing and FE simulation.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"63 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140972146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-312
D. Farioli
Abstract. This paper investigates the potential for remanufacturing aluminium sheets from end-of-life vehicles (ELVs), specifically focusing on car hoods. The study explores various pre-flattening procedures and reshaping techniques, with warm flattening showing promise despite challenges such as paint degradation. A Design of Experiment (DoE) was used to assess the impact of various factors on the flattening process, and Finite Element (FE) simulations were used to validate the experimental findings. An economic feasibility analysis was also conducted, which revealed that while technically feasible, the economic viability of this remanufacturing process is currently challenging due to the high costs compared to purchasing new sheets. However, with the increasing use of aluminium in automotive body panels and potential market shifts, these remanufacturing initiatives could become economically viable in the future, contributing to sustainability goals in the automotive sector.
{"title":"Remanufacturing process chain for end-of-life aluminium car body parts: Technical and economic analysis","authors":"D. Farioli","doi":"10.21741/9781644903131-312","DOIUrl":"https://doi.org/10.21741/9781644903131-312","url":null,"abstract":"Abstract. This paper investigates the potential for remanufacturing aluminium sheets from end-of-life vehicles (ELVs), specifically focusing on car hoods. The study explores various pre-flattening procedures and reshaping techniques, with warm flattening showing promise despite challenges such as paint degradation. A Design of Experiment (DoE) was used to assess the impact of various factors on the flattening process, and Finite Element (FE) simulations were used to validate the experimental findings. An economic feasibility analysis was also conducted, which revealed that while technically feasible, the economic viability of this remanufacturing process is currently challenging due to the high costs compared to purchasing new sheets. However, with the increasing use of aluminium in automotive body panels and potential market shifts, these remanufacturing initiatives could become economically viable in the future, contributing to sustainability goals in the automotive sector.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"36 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140972670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-123
Kaisei Akiyama
Abstract. The tension-compression asymmetry (TCA, referred to as the strength differential effect, SDE, for annealed materials) of a 1.1-mm-thick 6000-series aluminum alloy sheet, A6116-T4, which is 3-months age hardened is measured using a uniaxial tensile test and an in-plane compression test. It is found that the in-plane compressive flow stress is 1-7 % higher than the uniaxial tensile flow stress; therefore, the material exhibits the SDE. Moreover, a stacked compression test in the normal (through-thickness) direction (ND) of the test sample is also performed to measure the hydrostatic stress dependence of the yield stress. It is found that the uniaxial compressive flow stress in the ND is 4-9 % higher than the equibiaxial tensile flow stress measured using a cruciform equibiaxial tension test (ISO 16842); therefore, the hydrostatic stress dependence of the yield stress is confirmed. Hence, it is concluded that the SDE observed in A6116-T4 is caused by the hydrostatic stress dependence of the yield stress.
{"title":"Measurement and analysis of the strength differential effect of 6000-series aluminum alloy sheet","authors":"Kaisei Akiyama","doi":"10.21741/9781644903131-123","DOIUrl":"https://doi.org/10.21741/9781644903131-123","url":null,"abstract":"Abstract. The tension-compression asymmetry (TCA, referred to as the strength differential effect, SDE, for annealed materials) of a 1.1-mm-thick 6000-series aluminum alloy sheet, A6116-T4, which is 3-months age hardened is measured using a uniaxial tensile test and an in-plane compression test. It is found that the in-plane compressive flow stress is 1-7 % higher than the uniaxial tensile flow stress; therefore, the material exhibits the SDE. Moreover, a stacked compression test in the normal (through-thickness) direction (ND) of the test sample is also performed to measure the hydrostatic stress dependence of the yield stress. It is found that the uniaxial compressive flow stress in the ND is 4-9 % higher than the equibiaxial tensile flow stress measured using a cruciform equibiaxial tension test (ISO 16842); therefore, the hydrostatic stress dependence of the yield stress is confirmed. Hence, it is concluded that the SDE observed in A6116-T4 is caused by the hydrostatic stress dependence of the yield stress.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"21 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140974384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-132
A. Yamanaka
Abstract. This study proposes a new method for the inverse estimation of the parameters included in material models from full-field measurement data that are obtained using the digital image correlation method. This approach is based on data assimilation according to the Bayes’ theorem (Bayesian data assimilation). In this study, we demonstrate the assimilation of experimental data obtained from uniaxial tensile, forming, and fracture tests of aluminum alloys into elastoplastic finite element and phase-field crack propagation simulations. The proposed method allows the simultaneous estimation of multiple material model parameters. The Bayesian data assimilation is a promising methodology for estimating the parameters of different material models and constructing digital twins of material deformation.
{"title":"Inverse estimation of material model parameters using Bayesian data assimilation","authors":"A. Yamanaka","doi":"10.21741/9781644903131-132","DOIUrl":"https://doi.org/10.21741/9781644903131-132","url":null,"abstract":"Abstract. This study proposes a new method for the inverse estimation of the parameters included in material models from full-field measurement data that are obtained using the digital image correlation method. This approach is based on data assimilation according to the Bayes’ theorem (Bayesian data assimilation). In this study, we demonstrate the assimilation of experimental data obtained from uniaxial tensile, forming, and fracture tests of aluminum alloys into elastoplastic finite element and phase-field crack propagation simulations. The proposed method allows the simultaneous estimation of multiple material model parameters. The Bayesian data assimilation is a promising methodology for estimating the parameters of different material models and constructing digital twins of material deformation.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"6 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140972826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-8
Lilou de Peindray d'Ambelle
Abstract. Directed energy deposition (DED) is an additive manufacturing process with growing industrial interests. Nonetheless, its industrialization will not be possible until it is fully mature. Such maturity lies in the upstream research to optimize and control it. In DED, process parameters, physical quantities and parts properties are interrelated which makes it a complex process. To have a better understanding of these relations, the experimental approach of instrumentation has been chosen. Multi-sensor method has been implemented for its more extensive possibilities in comparison to single-sensor methods. A bichromatic pyrometer was coupled to an IR camera to measure the temperature distributions in real time. Post-process characterizations of the aspects and geometries of the parts were related to the sensors’ measurements and consequently, to the process parameters. Twelves sets of parameters were tested to conclude that the energy input impacts the size of the melting pool and the temperature distribution. High energies lead to defects such as edge defects and layer thickening but can mitigate surface roughness. Both the pyrometer and camera proved to have a relevance in this study for the enhancement of the DED process.
{"title":"Thermal multi-sensor instrumentation for the enhancement of a directed energy deposition process","authors":"Lilou de Peindray d'Ambelle","doi":"10.21741/9781644903131-8","DOIUrl":"https://doi.org/10.21741/9781644903131-8","url":null,"abstract":"Abstract. Directed energy deposition (DED) is an additive manufacturing process with growing industrial interests. Nonetheless, its industrialization will not be possible until it is fully mature. Such maturity lies in the upstream research to optimize and control it. In DED, process parameters, physical quantities and parts properties are interrelated which makes it a complex process. To have a better understanding of these relations, the experimental approach of instrumentation has been chosen. Multi-sensor method has been implemented for its more extensive possibilities in comparison to single-sensor methods. A bichromatic pyrometer was coupled to an IR camera to measure the temperature distributions in real time. Post-process characterizations of the aspects and geometries of the parts were related to the sensors’ measurements and consequently, to the process parameters. Twelves sets of parameters were tested to conclude that the energy input impacts the size of the melting pool and the temperature distribution. High energies lead to defects such as edge defects and layer thickening but can mitigate surface roughness. Both the pyrometer and camera proved to have a relevance in this study for the enhancement of the DED process.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"58 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140973359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-208
Liam Cloëz
Abstract. This paper is part of a study focusing on the elaboration of accurate component with complex geometries using bio-sourced as an alternative to petrochemical polymer. The bio-sourced and biodegradable in this study is composed of a Poly Lactic Acid (PLA) matrix and hemp fibers. The final component is obtained by injection followed by a machining operation. the final component is obtained by injection followed by a machining finishing operation. Injection molding will be carried out to be compared with 3D printing on economic, environmental, production and workpiece quality criteria. This paper focuses only on the combination of two processes, injection molding followed by machining on poly (L-lactic acid) or PLLA which is biobased and biodegradable. After injecting the workpiece, thermo-physical characterization tests are realized on PLLA polymer. Rheology, thermal and mechanical tests are carried out in order to study thermomechanical behavior and to understand material flow phenomena at different temperatures and shear rates. The objective of this paper is to overcome the technical challenges of milling this material without any lubricant. In an upcoming project, various machining operations will be carried out such as turning to study continuous cutting, or milling to study discontinuous cutting on workpieces reinforced with bio-sourced fibers as hemp.
{"title":"Machinability of PLA obtained by injection molding under a dry milling process","authors":"Liam Cloëz","doi":"10.21741/9781644903131-208","DOIUrl":"https://doi.org/10.21741/9781644903131-208","url":null,"abstract":"Abstract. This paper is part of a study focusing on the elaboration of accurate component with complex geometries using bio-sourced as an alternative to petrochemical polymer. The bio-sourced and biodegradable in this study is composed of a Poly Lactic Acid (PLA) matrix and hemp fibers. The final component is obtained by injection followed by a machining operation. the final component is obtained by injection followed by a machining finishing operation. Injection molding will be carried out to be compared with 3D printing on economic, environmental, production and workpiece quality criteria. This paper focuses only on the combination of two processes, injection molding followed by machining on poly (L-lactic acid) or PLLA which is biobased and biodegradable. After injecting the workpiece, thermo-physical characterization tests are realized on PLLA polymer. Rheology, thermal and mechanical tests are carried out in order to study thermomechanical behavior and to understand material flow phenomena at different temperatures and shear rates. The objective of this paper is to overcome the technical challenges of milling this material without any lubricant. In an upcoming project, various machining operations will be carried out such as turning to study continuous cutting, or milling to study discontinuous cutting on workpieces reinforced with bio-sourced fibers as hemp.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"72 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140973714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-1
C. Bruni
Abstract. The realization of the additive manufactured components requires the understanding of the variables having an effect on the physical final geometry. One of them is represented by the initial digital information with required tolerance, in particular where the different parts such as planar and curved ones need to be connected together. The other important variable is represented by the extruding conditions in FDM of PLA blend materials. The temperature setting with which to reduce the induced tensions, the volume variation and warpage is determined.
{"title":"Modeling fused deposition of PLA by analysis of the layers","authors":"C. Bruni","doi":"10.21741/9781644903131-1","DOIUrl":"https://doi.org/10.21741/9781644903131-1","url":null,"abstract":"Abstract. The realization of the additive manufactured components requires the understanding of the variables having an effect on the physical final geometry. One of them is represented by the initial digital information with required tolerance, in particular where the different parts such as planar and curved ones need to be connected together. The other important variable is represented by the extruding conditions in FDM of PLA blend materials. The temperature setting with which to reduce the induced tensions, the volume variation and warpage is determined.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"16 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140976685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-27
Théo LE SAINT
Abstract. Mechanical properties of Laser Power Bed Fusion (LPBF) parts, and particularly fatigue properties, are heavily affected by defects including surface roughness or porosity. To mitigate the occurrence of these defects, in-situ and on-line corrective measures can be implemented to the fabrication process, among them, rescanning, which consists in remelting an already solidified layer. Initially porous LPBF samples were created and then rescanned using different scanning parameters and strategies. Results show that it is possible to regain part’s health, compared to a standardly processed one, in terms of density, hardness and even improved roughness. This remelting process is known to refine microstructure of fabricated materials as well as reduce surface roughness and porosity without requiring further post-processing steps. Therefore, employing rescanning as a corrective technique appears to be a promising approach for rectifying detected defects during the fabrication process. The objective of this study is to assess the corrective capabilities of different rescanning strategies to restore the microstructure of an initially porous 316L LPBF simulating a defected part. This study shows that various rescanning strategies allow for densification of initially porous material from 98.83 ± 0.20 % to 99.75 ± 0.09 %, as well as lateral surface roughness reduction from Ra 20.2 ± 5.2 µm to Ra 12.7 ± 0.1 µm and microhardness increase from 243 ± 5 HV0.5 to 253 ± 3 HV0.5.
{"title":"Corrective capabilities of different rescanning strategies to restore microstructure and density of initially porous 316L laser powder bed fusion","authors":"Théo LE SAINT","doi":"10.21741/9781644903131-27","DOIUrl":"https://doi.org/10.21741/9781644903131-27","url":null,"abstract":"Abstract. Mechanical properties of Laser Power Bed Fusion (LPBF) parts, and particularly fatigue properties, are heavily affected by defects including surface roughness or porosity. To mitigate the occurrence of these defects, in-situ and on-line corrective measures can be implemented to the fabrication process, among them, rescanning, which consists in remelting an already solidified layer. Initially porous LPBF samples were created and then rescanned using different scanning parameters and strategies. Results show that it is possible to regain part’s health, compared to a standardly processed one, in terms of density, hardness and even improved roughness. This remelting process is known to refine microstructure of fabricated materials as well as reduce surface roughness and porosity without requiring further post-processing steps. Therefore, employing rescanning as a corrective technique appears to be a promising approach for rectifying detected defects during the fabrication process. The objective of this study is to assess the corrective capabilities of different rescanning strategies to restore the microstructure of an initially porous 316L LPBF simulating a defected part. This study shows that various rescanning strategies allow for densification of initially porous material from 98.83 ± 0.20 % to 99.75 ± 0.09 %, as well as lateral surface roughness reduction from Ra 20.2 ± 5.2 µm to Ra 12.7 ± 0.1 µm and microhardness increase from 243 ± 5 HV0.5 to 253 ± 3 HV0.5.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"59 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140974471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-283
Shixian Li
Abstract. Fused filament fabrication (FFF) as an additive manufacturing process, is a thermal driven method used to produce continuous fiber reinforced composites for engineering applications. Interlayer delamination is a significant concern for composites manufactured by FFF process. To address the problem of interlayer delamination and enhance the macro-mechanical properties of FFF fiber composites, it is necessary to study the thermal behavior of continuous fiber filled composites during the deposition process. A thermal simulation model with the consideration of continuous fiber was proposed. The numerical simulations reproduce the trends of experimental temperature evolution. When the continuous fiber phase is omitted from the heat transfer model, the predicted reheating temperature at the interface is lower compared to the temperature measured via IR monitoring. This result highlights the critical necessity of developing a numerical model that takes the continuous fiber phase into account in order to accurately predict the reheating temperature at the interface. Such a model is essential for deeper exploration into the adhesion mechanisms between adjacent layers and adjacent filaments.
{"title":"Analysis of thermal behavior in 3D printing of continuous fiber reinforced polymer composites","authors":"Shixian Li","doi":"10.21741/9781644903131-283","DOIUrl":"https://doi.org/10.21741/9781644903131-283","url":null,"abstract":"Abstract. Fused filament fabrication (FFF) as an additive manufacturing process, is a thermal driven method used to produce continuous fiber reinforced composites for engineering applications. Interlayer delamination is a significant concern for composites manufactured by FFF process. To address the problem of interlayer delamination and enhance the macro-mechanical properties of FFF fiber composites, it is necessary to study the thermal behavior of continuous fiber filled composites during the deposition process. A thermal simulation model with the consideration of continuous fiber was proposed. The numerical simulations reproduce the trends of experimental temperature evolution. When the continuous fiber phase is omitted from the heat transfer model, the predicted reheating temperature at the interface is lower compared to the temperature measured via IR monitoring. This result highlights the critical necessity of developing a numerical model that takes the continuous fiber phase into account in order to accurately predict the reheating temperature at the interface. Such a model is essential for deeper exploration into the adhesion mechanisms between adjacent layers and adjacent filaments.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"139 30","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140976443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-15DOI: 10.21741/9781644903131-131
Martin L. Kölüs
Abstract. Knowing the large strain flow curve is essential for many simulation processes in the sheet metal forming technology. A prominent example is the clinching, when the strains are one magnitude higher than in tension, but a simple deep-drawing process could also lead to appropriately large strains. To obtain the flow stress - plastic strain curves beyond the range of tension, several processes are known. In the most multi-axial cases, a conversion factor based on the work equivalence is usually applied on the measurement results to obtain the equivalent quantities. However, at compressive experiments, the friction and the geometrical issues may distort the curve shape even further, hiding the real material behavior. In this study we investigate the effect of the friction determination method and the value of the friction coefficient on the curve shape. Pressure dependent and constant friction coefficients were inversely specified by disk compression tests and related finite element modeling. In possession of the friction values, the conversions of the physically measured compressive stress to equivalent flow stress during disk and stack compression tests with different height-diameter ratios are discussed here.
{"title":"The effect of friction compensation on the slope of flow curves obtained by stack compression tests","authors":"Martin L. Kölüs","doi":"10.21741/9781644903131-131","DOIUrl":"https://doi.org/10.21741/9781644903131-131","url":null,"abstract":"Abstract. Knowing the large strain flow curve is essential for many simulation processes in the sheet metal forming technology. A prominent example is the clinching, when the strains are one magnitude higher than in tension, but a simple deep-drawing process could also lead to appropriately large strains. To obtain the flow stress - plastic strain curves beyond the range of tension, several processes are known. In the most multi-axial cases, a conversion factor based on the work equivalence is usually applied on the measurement results to obtain the equivalent quantities. However, at compressive experiments, the friction and the geometrical issues may distort the curve shape even further, hiding the real material behavior. In this study we investigate the effect of the friction determination method and the value of the friction coefficient on the curve shape. Pressure dependent and constant friction coefficients were inversely specified by disk compression tests and related finite element modeling. In possession of the friction values, the conversions of the physically measured compressive stress to equivalent flow stress during disk and stack compression tests with different height-diameter ratios are discussed here.","PeriodicalId":515987,"journal":{"name":"Materials Research Proceedings","volume":"57 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140973219","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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