Pub Date : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0041
Paul L. Briant, Louis G. Malito, J. Schaffer, T. Hamilton
Typical S/N type testing to determine the fatigue limit of Nitinol is done over a range of strain amplitudes; however, each specimen sees only a single peak strain amplitude during cycling. The effect of variable loading on Nitinol is therefore not understood. The purpose of this study was to evaluate any potential cumulative fatigue effect of combining low strain amplitude cycles with high strain amplitudes cycles on Nitinol wire apex specimens. A series of fatigue tests were performed to evaluate the fatigue response of Nitinol to variable loading. The results demonstrated that fatigue cycles at lower strain amplitudes can limit the number of higher amplitude cycles to failure in a variable loading scenario. However, the results also indicate that a small number of higher amplitude cycles can dominate the fatigue damage; almost all fractures occurred shortly after completing a section of higher amplitude cycles.
{"title":"Cumulative Fatigue of Nitinol due to Multiple Applied Cyclic Strains","authors":"Paul L. Briant, Louis G. Malito, J. Schaffer, T. Hamilton","doi":"10.31399/asm.cp.smst2022p0041","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0041","url":null,"abstract":"\u0000 Typical S/N type testing to determine the fatigue limit of Nitinol is done over a range of strain amplitudes; however, each specimen sees only a single peak strain amplitude during cycling. The effect of variable loading on Nitinol is therefore not understood. The purpose of this study was to evaluate any potential cumulative fatigue effect of combining low strain amplitude cycles with high strain amplitudes cycles on Nitinol wire apex specimens. A series of fatigue tests were performed to evaluate the fatigue response of Nitinol to variable loading. The results demonstrated that fatigue cycles at lower strain amplitudes can limit the number of higher amplitude cycles to failure in a variable loading scenario. However, the results also indicate that a small number of higher amplitude cycles can dominate the fatigue damage; almost all fractures occurred shortly after completing a section of higher amplitude cycles.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131152861","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0065
P. Sedlák, M. Frost, H. Seiner, L. Heller, P. Šittner
This paper presents an extension of a well-established constitutive model for NiTi covering both reversible (elastic, martensitic transformation, martensite reorientation) and irreversible (plastic) deformation mechanisms. Besides the inclusion of mechanisms of plastic deformation in both austenitic and martensitic phases in an independent manner, the model also newly captures more complex coupled phenomena of martensitic transformation and plastic deformation, such as transformation-induced plasticity, stabilization of martensite by plastic deformation, or plasticity-induced microstrain heterogeneity leading to functional fatigue. Despite a large number of different mechanisms involved in the model, which is reflected by a considerable number of internal parameters introduced for the description of the evolving microstructure of the material, the model still brings a basic, simple phenomenological understanding of the coupled transformation-plasticity proceeding in NiTi. After successful implementation to FEM software, the model provides new possibilities for simulations of NiTi components' behavior and processing.
{"title":"Thermodynamical Model of NiTi SMA Including Plastic Deformation Mechanisms","authors":"P. Sedlák, M. Frost, H. Seiner, L. Heller, P. Šittner","doi":"10.31399/asm.cp.smst2022p0065","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0065","url":null,"abstract":"\u0000 This paper presents an extension of a well-established constitutive model for NiTi covering both reversible (elastic, martensitic transformation, martensite reorientation) and irreversible (plastic) deformation mechanisms. Besides the inclusion of mechanisms of plastic deformation in both austenitic and martensitic phases in an independent manner, the model also newly captures more complex coupled phenomena of martensitic transformation and plastic deformation, such as transformation-induced plasticity, stabilization of martensite by plastic deformation, or plasticity-induced microstrain heterogeneity leading to functional fatigue. Despite a large number of different mechanisms involved in the model, which is reflected by a considerable number of internal parameters introduced for the description of the evolving microstructure of the material, the model still brings a basic, simple phenomenological understanding of the coupled transformation-plasticity proceeding in NiTi. After successful implementation to FEM software, the model provides new possibilities for simulations of NiTi components' behavior and processing.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123661443","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0043
M. Frotscher, M. Kiekbusch, S. Mews, A. Knopp, D. Serowietzki
The temperature difference between active austenite finish temperature, Af, and the intended operating temperature in the range of 3.2 °C to 20.8 °C. has been reported to have an influence on the fatigue lifetime of a pseudoelastic shape-memory device. The negative effect on fatigue life increases with the temperature difference between active Af and, in case of a biomedical device, 37 °C body temperature. In this study, samples were prepared and processed in a manner to replicate aspects of the complex manufacturing process, device design, and geometry of state-of-the-art stents, and physiological loading conditions. Following explantation from the mock vessels after fatigue testing, the stents were inspected using optical microscopy to detect and document the location and number of strut fractures. The fatigue results were compared and assessed for statistical significance between the groups with various active Af temperatures. The variations in the heat treatments, as part of the manufacturing process, resulted in three distinct groups of samples with varying target active Af temperatures. These variances corresponded to differences in fatigue damage.
{"title":"Influence of Active Af on the Fatigue Performance of Peripheral Stents Subjected to Physiological Loading Conditions","authors":"M. Frotscher, M. Kiekbusch, S. Mews, A. Knopp, D. Serowietzki","doi":"10.31399/asm.cp.smst2022p0043","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0043","url":null,"abstract":"\u0000 The temperature difference between active austenite finish temperature, Af, and the intended operating temperature in the range of 3.2 °C to 20.8 °C. has been reported to have an influence on the fatigue lifetime of a pseudoelastic shape-memory device. The negative effect on fatigue life increases with the temperature difference between active Af and, in case of a biomedical device, 37 °C body temperature. In this study, samples were prepared and processed in a manner to replicate aspects of the complex manufacturing process, device design, and geometry of state-of-the-art stents, and physiological loading conditions. Following explantation from the mock vessels after fatigue testing, the stents were inspected using optical microscopy to detect and document the location and number of strut fractures. The fatigue results were compared and assessed for statistical significance between the groups with various active Af temperatures. The variations in the heat treatments, as part of the manufacturing process, resulted in three distinct groups of samples with varying target active Af temperatures. These variances corresponded to differences in fatigue damage.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114557926","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0055
G. Bigelow, O. Benafan, Zachary D. Toom
This presentation reports on work to create user friendly software to aid in automated data analysis of tests to characterize the shape memory response of alloys. This effort has developed and produced software capable of automated analysis of test data produced using standard test methods and variations of these methods. This software provides a uniform method for analyzing data, which reduces analysis time and reduces error/variation due to different user and organization analysis methods. The software will allow analyzed data to be reported in the ASTM format for material certification, or as compiled data that can be directly imported into the NASA Shape Memory Material Database.
{"title":"SMAnalytics – An Automated Software for the Analysis of Shape Memory Alloy Test Data","authors":"G. Bigelow, O. Benafan, Zachary D. Toom","doi":"10.31399/asm.cp.smst2022p0055","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0055","url":null,"abstract":"\u0000 This presentation reports on work to create user friendly software to aid in automated data analysis of tests to characterize the shape memory response of alloys. This effort has developed and produced software capable of automated analysis of test data produced using standard test methods and variations of these methods. This software provides a uniform method for analyzing data, which reduces analysis time and reduces error/variation due to different user and organization analysis methods. The software will allow analyzed data to be reported in the ASTM format for material certification, or as compiled data that can be directly imported into the NASA Shape Memory Material Database.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129689303","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0081
A. Keck, Katarzyna Plaskonka-Weisenburger, S. Knoll, J. Ulmer, A. Pelton
The continuous rolling of Nitinol alloys is a metalworking process with the ability to produce large quantities of sheet with uniform properties for the use in actuation applications in motion systems with cyclic loads. Great advantages of continuous rolling in comparison with other manufacturing methods are the cold work and heat treatment steps and their ability to influence the properties of the product and keep them in a very tight window over the width and the length of the process. Those tightly controlled properties are key-requirements to use the continuous rolled Nitinol material for subsequent automated processes like stamping in progressive dies or deep- drawing. It is also required for efficient reel-to-reel laser or EDM cutting. The primary objective of this work is to evaluate and obtain the properties of Nitinol continuously flat-rolled sheets and optimization of the process parameters by fatigue evaluation.
{"title":"Nitinol Continuously Flat-Rolled Sheet and their Properties","authors":"A. Keck, Katarzyna Plaskonka-Weisenburger, S. Knoll, J. Ulmer, A. Pelton","doi":"10.31399/asm.cp.smst2022p0081","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0081","url":null,"abstract":"\u0000 The continuous rolling of Nitinol alloys is a metalworking process with the ability to produce large quantities of sheet with uniform properties for the use in actuation applications in motion systems with cyclic loads. Great advantages of continuous rolling in comparison with other manufacturing methods are the cold work and heat treatment steps and their ability to influence the properties of the product and keep them in a very tight window over the width and the length of the process. Those tightly controlled properties are key-requirements to use the continuous rolled Nitinol material for subsequent automated processes like stamping in progressive dies or deep- drawing. It is also required for efficient reel-to-reel laser or EDM cutting. The primary objective of this work is to evaluate and obtain the properties of Nitinol continuously flat-rolled sheets and optimization of the process parameters by fatigue evaluation.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128409446","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0028
G. Ouyang, Benjamin Hilliard, Jun Cui
Elastocaloric applications exploit the latent heat from a shape memory alloy (SMA) through its stress-induced phase transformation. The elastocaloric potential of a SMA depends on its latent heat, critical transformation stress, hysteresis, heat capacity and conductivity, and, most importantly, its cost-effectiveness. Increasing the latent heat and improving the transformation characteristics are critical to increasing the elastocaloric potential in copper-based SMAs, which depend heavily on their compositions and processing conditions. This paper reports on a comprehensive compositional optimization effort to maximize latent heat while maintaining the near room temperature transition window and minimizing hysteresis for copper-based SMAs. The effort uses a high throughput combinatorial approach to prepare and scan multiple samples with different compositions. The transformation characteristics of grouped samples were determined simultaneously using a novel differential thermal analysis (DTA) method via thermal imaging. Differential scanning calorimetry (DSC) was used to examine the down-selected compositions for verification.
{"title":"Elastocaloric Potential in Copper-Based SMAs through a Combinatorial Approach","authors":"G. Ouyang, Benjamin Hilliard, Jun Cui","doi":"10.31399/asm.cp.smst2022p0028","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0028","url":null,"abstract":"\u0000 Elastocaloric applications exploit the latent heat from a shape memory alloy (SMA) through its stress-induced phase transformation. The elastocaloric potential of a SMA depends on its latent heat, critical transformation stress, hysteresis, heat capacity and conductivity, and, most importantly, its cost-effectiveness. Increasing the latent heat and improving the transformation characteristics are critical to increasing the elastocaloric potential in copper-based SMAs, which depend heavily on their compositions and processing conditions. This paper reports on a comprehensive compositional optimization effort to maximize latent heat while maintaining the near room temperature transition window and minimizing hysteresis for copper-based SMAs. The effort uses a high throughput combinatorial approach to prepare and scan multiple samples with different compositions. The transformation characteristics of grouped samples were determined simultaneously using a novel differential thermal analysis (DTA) method via thermal imaging. Differential scanning calorimetry (DSC) was used to examine the down-selected compositions for verification.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124404776","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0067
M. Frost, P. Sedlák, A. Jury, L. Heller
Specific heat treatment or addition of a ternary element may induce a two-stage transformation sequence in NiTi shape memory alloys (SMA). A typical example of intermediating phases is so-called R-phase, a rhombohedral distortion of the cubic austenitic phase, which exhibits much lower transformation strain and thermal hysteresis than the subsequent transition to monoclinic martensite. In specific alloys, e.g., in NiTi slightly enriched by iron, the temperature and stress intervals in which R-phase is stable are quite broad. Hence, the influence of R-phase on the macroscopic (thermo)mechanical response should be considered when developing and designing products from these alloys. Within this context, tailored constitutive models allowing to reproduce the response in complex loading scenarios without additional experimental effort can be extremely beneficial. This paper presents an enhanced constitutive model for NiTi SMA featuring the R-phase transition. The model recognizes R-phase as a distinct phase, respects the coupled influence of stress and temperature on any phase transformation, and covers reorientation (reconfiguration) of both martensite and R-phase with applied stress. The core of the model consists of two material functions: one captures the energy stored in the material at a given thermodynamic state, the other defines the energy released during dissipative processes, which are considered rate-independent. The model was validated through a direct comparison of experimental tests (isothermal tensile tests, isobaric thermal tests, recovery stress tests) with simulated counterparts.
{"title":"Constitutive Model for Ni-Ti-Fe Shape Memory Alloys Exhibiting Pronounced R-Phase Transformation","authors":"M. Frost, P. Sedlák, A. Jury, L. Heller","doi":"10.31399/asm.cp.smst2022p0067","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0067","url":null,"abstract":"\u0000 Specific heat treatment or addition of a ternary element may induce a two-stage transformation sequence in NiTi shape memory alloys (SMA). A typical example of intermediating phases is so-called R-phase, a rhombohedral distortion of the cubic austenitic phase, which exhibits much lower transformation strain and thermal hysteresis than the subsequent transition to monoclinic martensite. In specific alloys, e.g., in NiTi slightly enriched by iron, the temperature and stress intervals in which R-phase is stable are quite broad. Hence, the influence of R-phase on the macroscopic (thermo)mechanical response should be considered when developing and designing products from these alloys. Within this context, tailored constitutive models allowing to reproduce the response in complex loading scenarios without additional experimental effort can be extremely beneficial. This paper presents an enhanced constitutive model for NiTi SMA featuring the R-phase transition. The model recognizes R-phase as a distinct phase, respects the coupled influence of stress and temperature on any phase transformation, and covers reorientation (reconfiguration) of both martensite and R-phase with applied stress. The core of the model consists of two material functions: one captures the energy stored in the material at a given thermodynamic state, the other defines the energy released during dissipative processes, which are considered rate-independent. The model was validated through a direct comparison of experimental tests (isothermal tensile tests, isobaric thermal tests, recovery stress tests) with simulated counterparts.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134302519","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0089
Guoan Zhou, Q. Sun
A promising elastocaloric cooling technology (one of the solid-state cooling technologies) does not require any potentially harmful vaporous refrigerants. Its basic working principle, the martensitic transformation and its reverse transformation of shape memory alloys (SMAs) such as NiTi, NiTiCu, and NiFeGaC is one of the first-order non-diffusible phase transitions between a high-temperature phase (the austenite phase) of a B2 cubic structure and a low-temperature phase (the martensite phase) of a B19' monoclinic structure. This paper investigates the compression behaviors of different NiTi regenerator structures through fatigue tests. An optimized 3-layer sample shows promise to be used in elastocaloric cooling prototypes and gives insight into the structural optimization of regenerators.
{"title":"Compression Behaviors of Different Geometry-Designed NiTi Refrigerants","authors":"Guoan Zhou, Q. Sun","doi":"10.31399/asm.cp.smst2022p0089","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0089","url":null,"abstract":"\u0000 A promising elastocaloric cooling technology (one of the solid-state cooling technologies) does not require any potentially harmful vaporous refrigerants. Its basic working principle, the martensitic transformation and its reverse transformation of shape memory alloys (SMAs) such as NiTi, NiTiCu, and NiFeGaC is one of the first-order non-diffusible phase transitions between a high-temperature phase (the austenite phase) of a B2 cubic structure and a low-temperature phase (the martensite phase) of a B19' monoclinic structure. This paper investigates the compression behaviors of different NiTi regenerator structures through fatigue tests. An optimized 3-layer sample shows promise to be used in elastocaloric cooling prototypes and gives insight into the structural optimization of regenerators.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"378 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133346199","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0006
F. Calkins, D. Nicholson, A. Fassmann, P. Vijgen, Christopher Yeeles, O. Benafan, G. Bigelow, D. Gaydosh
Conventional vortex generators (VG) in aeronautical applications are static vanes mounted on aircraft surfaces used to improve aircraft efficiency during low speed operations. However, during the cruise phase of flight, these static devices are always deployed and produce drag penalties. With the goal of improving aircraft efficiency, Boeing in collaboration with NASA Glen Research Center have developed and successfully flight tested environmentally activated SMART-VGs that repeatedly and accurately retract during cruise and deploy during take- off and landing. This application is distinctively enabled by the ability of shape memory alloy (SMA) actuation to produce large work outputs in compact volumes and operate as both a sensor and actuator. The SMART-VG project highlighted here was built upon recent advancements in SMA rotary actuation technology that included improved alloy systems, design tools, best practices, published standards and high-level wind tunnel and flight test demonstrations. This program successfully matured and validated the targeted alloy development and associated design processes in a unique way by demonstrating shape memory alloy reconfigurable technology (SMART) in-flight. The data from this flight test is being used to optimize a next generation design of the SMART-VGs that will be tested in 2022.
{"title":"Shape Memory Alloy Actuated Vortex Generators: Development and Flight Test","authors":"F. Calkins, D. Nicholson, A. Fassmann, P. Vijgen, Christopher Yeeles, O. Benafan, G. Bigelow, D. Gaydosh","doi":"10.31399/asm.cp.smst2022p0006","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0006","url":null,"abstract":"\u0000 Conventional vortex generators (VG) in aeronautical applications are static vanes mounted on aircraft surfaces used to improve aircraft efficiency during low speed operations. However, during the cruise phase of flight, these static devices are always deployed and produce drag penalties. With the goal of improving aircraft efficiency, Boeing in collaboration with NASA Glen Research Center have developed and successfully flight tested environmentally activated SMART-VGs that repeatedly and accurately retract during cruise and deploy during take- off and landing. This application is distinctively enabled by the ability of shape memory alloy (SMA) actuation to produce large work outputs in compact volumes and operate as both a sensor and actuator. The SMART-VG project highlighted here was built upon recent advancements in SMA rotary actuation technology that included improved alloy systems, design tools, best practices, published standards and high-level wind tunnel and flight test demonstrations. This program successfully matured and validated the targeted alloy development and associated design processes in a unique way by demonstrating shape memory alloy reconfigurable technology (SMART) in-flight. The data from this flight test is being used to optimize a next generation design of the SMART-VGs that will be tested in 2022.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"80 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126019570","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 : 2022-05-16DOI: 10.31399/asm.cp.smst2022p0022
N. Bruno
Meta-magnetic shape memory alloys (MMSMAs) exhibit multi-physical couplings across a reversible first-order martensitic transition which leads to their potential applications in solid-state cooling, thermally or magnetically driven precision actuation, energy harvesting, and magnetic memory storage. Through their magneto-structural transitions and simultaneous transformation latent heat, MMSMAs are capable of the magnetocaloric effect (MCE) at two distinct operating temperatures (i.e., the critical martensitic transformation temperature and the ferromagnetic Curie point of either the austenite or martensite phase). In this study, the Refrigeration Capacity (RC) and Coefficient of Refrigeration Performance (CRP) in MMSMAs are shown to depend on the critical martensite transformation temperatures and, by extension, uniaxial mechanical stress. A loading sequence, namely the stress-assisted magnetic field-induced phase transformation (SAMFIT) is described, whereby mechanical stress and magnetic field are applied to an MMSMA specimen in sequence to effectively increase the thermal operating range and CRP for a single MMSMA composition.
{"title":"The Coefficient of Refrigeration Performance and Stress-Assisted Magnetocaloric Effect in Meta-Magnetic Shape Memory Alloys","authors":"N. Bruno","doi":"10.31399/asm.cp.smst2022p0022","DOIUrl":"https://doi.org/10.31399/asm.cp.smst2022p0022","url":null,"abstract":"\u0000 Meta-magnetic shape memory alloys (MMSMAs) exhibit multi-physical couplings across a reversible first-order martensitic transition which leads to their potential applications in solid-state cooling, thermally or magnetically driven precision actuation, energy harvesting, and magnetic memory storage. Through their magneto-structural transitions and simultaneous transformation latent heat, MMSMAs are capable of the magnetocaloric effect (MCE) at two distinct operating temperatures (i.e., the critical martensitic transformation temperature and the ferromagnetic Curie point of either the austenite or martensite phase). In this study, the Refrigeration Capacity (RC) and Coefficient of Refrigeration Performance (CRP) in MMSMAs are shown to depend on the critical martensite transformation temperatures and, by extension, uniaxial mechanical stress. A loading sequence, namely the stress-assisted magnetic field-induced phase transformation (SAMFIT) is described, whereby mechanical stress and magnetic field are applied to an MMSMA specimen in sequence to effectively increase the thermal operating range and CRP for a single MMSMA composition.","PeriodicalId":119283,"journal":{"name":"SMST 2022: Extended Abstracts from the International Conference on Shape Memory and Superelastic Technologies","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131113344","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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