Lauren Judkins, Richa Gupta, Christine Gabriele, Charles Tomonto, M. Hast, G. Manogharan
Rib fractures and chest flail injuries are life threatening injuries that often require surgical treatment using metal (e.g. titanium) fracture reconstruction plates and screws. Current implant designs do not account for the variable stiffness present in human ribs and are much stiffer than the native bone, causing undesirable clinical outcomes. In this preliminary study, groups of latticed test plates were designed with a body centered cubic (BCC) lattice and porosities ranging from 36–86%. Porosity was altered by changing lattice strut thickness between 0.225–0.425 mm and unit cell length between 1, 2, and 3 mm. The test plates were fabricated using an established laser powder bed fusion additive manufacturing process. Flexural strength (4-point bending) tests were performed at a strain rate of 1.3 mm/min to characterize changes in bending stiffness and strength. It was found that implant stiffness could be decreased by 15.7% (p = 0.068) by decreasing strut thickness from 0.425 to 0.225 mm and increasing unit cell length from 1 to 3 mm. The results of this preliminary experiment serve as guidelines for the design of full-sized rib fracture reconstruction plates that contain a gradient lattice with varied mechanical properties to better match the behavior of intact ribs.
{"title":"On Additive Manufacturing of Rib Fracture Fixation Implants: The Role of Lattice Design","authors":"Lauren Judkins, Richa Gupta, Christine Gabriele, Charles Tomonto, M. Hast, G. Manogharan","doi":"10.1115/imece2021-73086","DOIUrl":"https://doi.org/10.1115/imece2021-73086","url":null,"abstract":"\u0000 Rib fractures and chest flail injuries are life threatening injuries that often require surgical treatment using metal (e.g. titanium) fracture reconstruction plates and screws. Current implant designs do not account for the variable stiffness present in human ribs and are much stiffer than the native bone, causing undesirable clinical outcomes. In this preliminary study, groups of latticed test plates were designed with a body centered cubic (BCC) lattice and porosities ranging from 36–86%. Porosity was altered by changing lattice strut thickness between 0.225–0.425 mm and unit cell length between 1, 2, and 3 mm. The test plates were fabricated using an established laser powder bed fusion additive manufacturing process. Flexural strength (4-point bending) tests were performed at a strain rate of 1.3 mm/min to characterize changes in bending stiffness and strength. It was found that implant stiffness could be decreased by 15.7% (p = 0.068) by decreasing strut thickness from 0.425 to 0.225 mm and increasing unit cell length from 1 to 3 mm. The results of this preliminary experiment serve as guidelines for the design of full-sized rib fracture reconstruction plates that contain a gradient lattice with varied mechanical properties to better match the behavior of intact ribs.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90177804","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}
Renewable energy and environmental preservation are two grand challenges in our society today. To address these two challenges, there is an increasing demand for energy storage devices made of green and biodegradable materials. State-of-the-art plant-based electrodes have problems of poor electrochemical performance, low reliability, and high manufacturing cost that pose major limitations in their use in flexible supercapacitors. In this research, a novel microwave irradiation synthesis is used to produce a high-performing electro-active lignin-based biomaterial. MnO2 particles are deposited on these lignin-based materials to impart pseudo-capacitance property. These electro-active materials were coated on an Al substrate and used as an anode with an AC-based cathode. A quasi-solid-state supercapacitor was assembled using a polymer-based gel electrolyte of PVA/H3PO4. SEM was performed to study morphology, porosity, and polydispersity of the lignin-based matrix. Cyclic voltammetry (CV) was employed to study the polarization resistance of the system. The cyclic charge-discharge (CCD) was performed to observe cyclic performance. The assembled supercapacitor exhibited a specific capacitance of 26 mF/g after 500 cycles with capacitance retention of ∼87% at 0.1 A/g. This work provides new insights into the synthesis of low-cost and scalable plant-based flexible supercapacitors.
可再生能源和环境保护是当今社会面临的两大挑战。为了解决这两个挑战，人们对绿色和可生物降解材料制成的储能设备的需求越来越大。目前最先进的植物电极存在电化学性能差、可靠性低、制造成本高等问题，这对其在柔性超级电容器中的应用构成了主要限制。在本研究中，采用一种新的微波辐照合成方法制备了一种高性能的电活性木质素基生物材料。在这些木质素基材料上沉积二氧化锰颗粒以获得赝电容特性。这些电活性材料被涂在铝衬底上，用作阳极和基于交流的阴极。采用PVA/H3PO4聚合物基凝胶电解质组装准固态超级电容器。利用扫描电镜研究了木质素基基质的形貌、孔隙度和多分散性。采用循环伏安法(CV)研究了该体系的极化电阻。通过循环充放电(CCD)观察循环性能。经过500次循环后，组装的超级电容器的比电容为26 mF/g，在0.1 a /g下电容保持率为87%。这项工作为低成本和可扩展的植物基柔性超级电容器的合成提供了新的见解。
{"title":"Microwave Synthesis of Plant-Based Supercapacitor Electrodes for Flexible Electronics","authors":"Siddhi Mehta, Swarn Jha, Weston Stewart, H. Liang","doi":"10.1115/imece2021-70062","DOIUrl":"https://doi.org/10.1115/imece2021-70062","url":null,"abstract":"\u0000 Renewable energy and environmental preservation are two grand challenges in our society today. To address these two challenges, there is an increasing demand for energy storage devices made of green and biodegradable materials. State-of-the-art plant-based electrodes have problems of poor electrochemical performance, low reliability, and high manufacturing cost that pose major limitations in their use in flexible supercapacitors. In this research, a novel microwave irradiation synthesis is used to produce a high-performing electro-active lignin-based biomaterial. MnO2 particles are deposited on these lignin-based materials to impart pseudo-capacitance property. These electro-active materials were coated on an Al substrate and used as an anode with an AC-based cathode. A quasi-solid-state supercapacitor was assembled using a polymer-based gel electrolyte of PVA/H3PO4. SEM was performed to study morphology, porosity, and polydispersity of the lignin-based matrix. Cyclic voltammetry (CV) was employed to study the polarization resistance of the system. The cyclic charge-discharge (CCD) was performed to observe cyclic performance. The assembled supercapacitor exhibited a specific capacitance of 26 mF/g after 500 cycles with capacitance retention of ∼87% at 0.1 A/g. This work provides new insights into the synthesis of low-cost and scalable plant-based flexible supercapacitors.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85818504","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 research presents a new coating on a metal substrate. A carbon steel substrate was used to apply Ni-SiC coatings of various ratios. Wear tests were performed on the coatings and substrate using a linearly reciprocating tribometer with a E52100 carbon steel counterpart. Scratch tests were performed with the same instrument using a tungsten carbide scratch tip. The addition of the coating was found to greatly improve the mechanical properties of the substrate. During experiments studying wear, an E52100 carbon steel ball counterpart was used and its damage was analyzed. This ball showed signs of wear while the coating surfaces showed no sign of abrasion but with only visible adhesive wear. Similarly, scratch tests showed far less material removal in the coating than substrate, showing greatly improved scratch resistance. Additionally, scratch coefficient of friction measured during these tests showed the addition of the coating decreased coefficient of friction to as low as 0.25 compared to the 0.4 of the substrate. The combination of these properties shows that this coating and application method is useful in a wide range of industries.
{"title":"Tribological Evaluation of a High-Performance Composite Coating","authors":"P. Renner, Mohamed Gharib, Hong Liang","doi":"10.1115/imece2021-73701","DOIUrl":"https://doi.org/10.1115/imece2021-73701","url":null,"abstract":"\u0000 This research presents a new coating on a metal substrate. A carbon steel substrate was used to apply Ni-SiC coatings of various ratios. Wear tests were performed on the coatings and substrate using a linearly reciprocating tribometer with a E52100 carbon steel counterpart. Scratch tests were performed with the same instrument using a tungsten carbide scratch tip. The addition of the coating was found to greatly improve the mechanical properties of the substrate. During experiments studying wear, an E52100 carbon steel ball counterpart was used and its damage was analyzed. This ball showed signs of wear while the coating surfaces showed no sign of abrasion but with only visible adhesive wear. Similarly, scratch tests showed far less material removal in the coating than substrate, showing greatly improved scratch resistance. Additionally, scratch coefficient of friction measured during these tests showed the addition of the coating decreased coefficient of friction to as low as 0.25 compared to the 0.4 of the substrate. The combination of these properties shows that this coating and application method is useful in a wide range of industries.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87466867","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}
Although structural instabilities have traditionally been avoided in design as undesirable causes of failure, the rapid and potentially significant energy changes that result from the large displacements induced by buckling have gained recent interest as a favorable design feature for systems whose intent is energy dissipation or energy storage. Computational methods to quantify the energy changes associated with buckling of a transversely loaded curved beam are developed in this work. The methods are then used to predict the occurrence of buckling based on initial geometry and input load. The influence of the parameters of the numerical approximation, such as mesh and time step, is also explored. Correlations are made between the simpler behavior of a truss structure and the more complex behavior of a curved beam so that analytical solutions may be used to guide the understanding of structures whose response can only be predicted computationally. The techniques which are presented can aid in the more efficient design of energy dissipation, transfer, and storage systems that take advantage of buckling instability phenomena.
{"title":"A Finite Element Based Method to Predict and Tailor the Energy Associated With Snap-Through Buckling of a Curved Beam","authors":"C. S. Florio","doi":"10.1115/imece2021-67793","DOIUrl":"https://doi.org/10.1115/imece2021-67793","url":null,"abstract":"\u0000 Although structural instabilities have traditionally been avoided in design as undesirable causes of failure, the rapid and potentially significant energy changes that result from the large displacements induced by buckling have gained recent interest as a favorable design feature for systems whose intent is energy dissipation or energy storage. Computational methods to quantify the energy changes associated with buckling of a transversely loaded curved beam are developed in this work. The methods are then used to predict the occurrence of buckling based on initial geometry and input load. The influence of the parameters of the numerical approximation, such as mesh and time step, is also explored. Correlations are made between the simpler behavior of a truss structure and the more complex behavior of a curved beam so that analytical solutions may be used to guide the understanding of structures whose response can only be predicted computationally. The techniques which are presented can aid in the more efficient design of energy dissipation, transfer, and storage systems that take advantage of buckling instability phenomena.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77052076","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}
Friction surfacing is a solid-state metal deposition technique suitable for a wide range of metallic materials. This technique results in coatings on surfaces for joining purposes or surface modification applications such as wear and corrosion performance improvements. In this study, a novel approach in friction surfacing is utilized in which the consumable tool deposits material from its side instead of the end of the tool, which has been employed in conventional friction surfacing. Frictional heat enables plastic deformation, which results in the depositing of the consumable material on the substrate surface. The process is carried out at temperatures below the melting point of the consumable material, resulting in a solid-state deposition process. In the current study, scanning electron microscopy and energy dispersive spectroscopy have been employed for the characterization of the interfaces and coatings. The results of this study exhibited that there is no elemental diffusion between the tool and substrate materials at the interface, showing that the process temperature was low enough to prevent plasticizing of the substrate surface.
{"title":"Characterization of Lateral Friction Surfaced AA6063 Coatings","authors":"Ebrahim Seidi, Scott F. Miller","doi":"10.1115/imece2021-67839","DOIUrl":"https://doi.org/10.1115/imece2021-67839","url":null,"abstract":"\u0000 Friction surfacing is a solid-state metal deposition technique suitable for a wide range of metallic materials. This technique results in coatings on surfaces for joining purposes or surface modification applications such as wear and corrosion performance improvements. In this study, a novel approach in friction surfacing is utilized in which the consumable tool deposits material from its side instead of the end of the tool, which has been employed in conventional friction surfacing. Frictional heat enables plastic deformation, which results in the depositing of the consumable material on the substrate surface. The process is carried out at temperatures below the melting point of the consumable material, resulting in a solid-state deposition process. In the current study, scanning electron microscopy and energy dispersive spectroscopy have been employed for the characterization of the interfaces and coatings. The results of this study exhibited that there is no elemental diffusion between the tool and substrate materials at the interface, showing that the process temperature was low enough to prevent plasticizing of the substrate surface.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"158 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77402962","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 use of Glass fiber reinforced plastics (GFRP) in underwater applications has been increasing in recent times, due to its superior durability and chemical stability in corrosive environments compared to metals. However, penetration of moisture in to the polymer matrix can adversely affect the mechanical properties of composite materials. In this study, the effect of exposure to plain water and simulated sea water (3.5% by weight NaCl salt) water on the mechanical properties of GFRP specimens has been analyzed. Tensile and three point bend tests were conducted on composite specimens with different moisture contents to characterize the mechanical degradation due to moisture absorption. Gravimetric tests were conducted on specimens to calculate the moisture absorption parameters. The results indicate that plain water is absorbed at a faster rate compared to salt water. Using these parameters, a transient moisture diffusion model was developed using commercial finite element software ABAQUS®. The results of tensile and three point bend testing indicate that both tensile and flexural properties of glass fiber reinforced epoxy composites degrade with exposure to plain water and salt water. Further, a coupled hygro-mechanical model was developed in ABAQUS® and the simulation results were compared with actual test results. Scanning electron Microscopy was used to examine the fracture surface of failed specimens. The cause for mechanical degradation seems to be the deterioration of fiber-matrix interface due to the penetration of water molecules.
{"title":"Effect of Moisture Absorption on the Tensile and Flexural Properties of Glass Fiber Reinforced Composite Materials","authors":"R. Prakash, V. Viswanath","doi":"10.1115/imece2021-69865","DOIUrl":"https://doi.org/10.1115/imece2021-69865","url":null,"abstract":"\u0000 The use of Glass fiber reinforced plastics (GFRP) in underwater applications has been increasing in recent times, due to its superior durability and chemical stability in corrosive environments compared to metals. However, penetration of moisture in to the polymer matrix can adversely affect the mechanical properties of composite materials. In this study, the effect of exposure to plain water and simulated sea water (3.5% by weight NaCl salt) water on the mechanical properties of GFRP specimens has been analyzed. Tensile and three point bend tests were conducted on composite specimens with different moisture contents to characterize the mechanical degradation due to moisture absorption. Gravimetric tests were conducted on specimens to calculate the moisture absorption parameters. The results indicate that plain water is absorbed at a faster rate compared to salt water. Using these parameters, a transient moisture diffusion model was developed using commercial finite element software ABAQUS®. The results of tensile and three point bend testing indicate that both tensile and flexural properties of glass fiber reinforced epoxy composites degrade with exposure to plain water and salt water. Further, a coupled hygro-mechanical model was developed in ABAQUS® and the simulation results were compared with actual test results. Scanning electron Microscopy was used to examine the fracture surface of failed specimens. The cause for mechanical degradation seems to be the deterioration of fiber-matrix interface due to the penetration of water molecules.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87319323","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}
With a significantly increasing demand for miniaturized titanium thin-walled products, micro forming using sheet metals is a promising approach with high productivity. However, once the sheet thickness is scaled down to a micro-scale, there are many unknowns in terms of size effect and its affected fracture behavior. In this research, the influence of grain size on the fracture behavior of commercially pure titanium sheets with a thickness of 0.1 mm was investigated by the uniaxial tensile tests combined with a digital image correlation measurement system. The ductile-to-brittle transformation of fracture behavior with the grain size increasing from 33.07 to 107.70 μm was revealed. Macroscopically, the elongation and critical fracture stress of CP-Ti samples decrease with the increase of grain size. According to the scanning electron microscopic observations, the number of dimples decreases with grain size increasing, while the cleavage planes and river patterns gradually dominate in the coarse grain fracture surface. To explore the fracture mechanism, the dislocation evolution of various grain sizes is further observed by a transmission electron microscope. The dislocation emission from crack-tips was revealed at different grain sizes. Significant dislocation pile-up at grain boundaries was observed in the specimen with a grain size of 33.07 μm. Those intense dislocations reduce the effective stress at the crack tip resulting in higher crack propagation resistance. Nevertheless, the dislocation density at crack-tip decreases strongly with the increase of grain size leading to high crack-tip effective stress and less crack plasticity. Hence cleavage fracture was dominated in coarse grain CP-Ti sheets.
{"title":"Ductile-to-Brittle Fracture Size Effect of Titanium Sheets in Micro/Meso-Scale Plastic Deformation","authors":"Lei Sun, Zhutian Xu, Linfa Peng, X. Lai","doi":"10.1115/imece2021-70083","DOIUrl":"https://doi.org/10.1115/imece2021-70083","url":null,"abstract":"\u0000 With a significantly increasing demand for miniaturized titanium thin-walled products, micro forming using sheet metals is a promising approach with high productivity. However, once the sheet thickness is scaled down to a micro-scale, there are many unknowns in terms of size effect and its affected fracture behavior. In this research, the influence of grain size on the fracture behavior of commercially pure titanium sheets with a thickness of 0.1 mm was investigated by the uniaxial tensile tests combined with a digital image correlation measurement system. The ductile-to-brittle transformation of fracture behavior with the grain size increasing from 33.07 to 107.70 μm was revealed. Macroscopically, the elongation and critical fracture stress of CP-Ti samples decrease with the increase of grain size. According to the scanning electron microscopic observations, the number of dimples decreases with grain size increasing, while the cleavage planes and river patterns gradually dominate in the coarse grain fracture surface. To explore the fracture mechanism, the dislocation evolution of various grain sizes is further observed by a transmission electron microscope. The dislocation emission from crack-tips was revealed at different grain sizes. Significant dislocation pile-up at grain boundaries was observed in the specimen with a grain size of 33.07 μm. Those intense dislocations reduce the effective stress at the crack tip resulting in higher crack propagation resistance. Nevertheless, the dislocation density at crack-tip decreases strongly with the increase of grain size leading to high crack-tip effective stress and less crack plasticity. Hence cleavage fracture was dominated in coarse grain CP-Ti sheets.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86225292","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}
Christopher Summers, Jonathan M. Weaver-Rosen, Anargyros Karakalas, R. Malak, D. Lagoudas
Novel design of more efficient, environmentally friendly, quiet, and cost-effective air transportation could be substantially benefited by introducing highly adaptive, multi-functional systems that are able to mimic the operation of biological systems, like birds. Altering the Outer Mold Line (OML) of an aircraft allows for achieving the optimal response under a wide range of operational conditions. In the framework of the “Adaptive Aerostructures for Revolutionary Civil Supersonic Transportation” project funded by NASA, an articulated panel mechanism controlled by Shape Memory Alloy (SMA) actuators is investigated as a means for reducing the perceived loudness of the sonic boom produced by a commercial aircraft when flying at supersonic speeds. A pair of SMA torque tubes is envisioned to induce the required rotation of the panels in order to achieve the desirable OML shapes. However, design objectives such as minimizing power consumption, mass, and cooling time are often competing and the selection of the optimal dimensions is neither elementary nor straightforward. In the research conducted herein, a case study is defined and realized for the optimal design of the SMA torque tubes as part of a larger morphing structure. In the early stages of design, engineers are often faced with the challenge of making decisions with incomplete information. For example, the designer must know the aerodynamic loads to choose the optimal dimensions, but the aerodynamic loads depend on aircraft dimensions. To enable detailed optimization in the early design stages, parametric optimization can be used to solve for the parameterized Pareto frontier. This parameterized Pareto frontier allows a designer to explore how the traditional Pareto frontier might change as exogenous parameters (the values of which are not yet fully known) change. In this work, the design variables under the control of the engineer are the dimensions of the torque tube, i.e. length, inner diameter, and thickness. The objectives are to minimize cooling time and maximize rigidity. The exogenous parameters outside of the designer’s control include the required actuation stroke and aerodynamic forces. Results show the effects of parameters on the objective tradeoffs and demonstrate how an engineer can choose an optimal solution once the parameter values are known.
{"title":"Parametric Optimization of SMA Torsional Actuators for Aircraft Morphing Applications","authors":"Christopher Summers, Jonathan M. Weaver-Rosen, Anargyros Karakalas, R. Malak, D. Lagoudas","doi":"10.1115/imece2021-73206","DOIUrl":"https://doi.org/10.1115/imece2021-73206","url":null,"abstract":"\u0000 Novel design of more efficient, environmentally friendly, quiet, and cost-effective air transportation could be substantially benefited by introducing highly adaptive, multi-functional systems that are able to mimic the operation of biological systems, like birds. Altering the Outer Mold Line (OML) of an aircraft allows for achieving the optimal response under a wide range of operational conditions. In the framework of the “Adaptive Aerostructures for Revolutionary Civil Supersonic Transportation” project funded by NASA, an articulated panel mechanism controlled by Shape Memory Alloy (SMA) actuators is investigated as a means for reducing the perceived loudness of the sonic boom produced by a commercial aircraft when flying at supersonic speeds. A pair of SMA torque tubes is envisioned to induce the required rotation of the panels in order to achieve the desirable OML shapes. However, design objectives such as minimizing power consumption, mass, and cooling time are often competing and the selection of the optimal dimensions is neither elementary nor straightforward. In the research conducted herein, a case study is defined and realized for the optimal design of the SMA torque tubes as part of a larger morphing structure. In the early stages of design, engineers are often faced with the challenge of making decisions with incomplete information. For example, the designer must know the aerodynamic loads to choose the optimal dimensions, but the aerodynamic loads depend on aircraft dimensions. To enable detailed optimization in the early design stages, parametric optimization can be used to solve for the parameterized Pareto frontier. This parameterized Pareto frontier allows a designer to explore how the traditional Pareto frontier might change as exogenous parameters (the values of which are not yet fully known) change. In this work, the design variables under the control of the engineer are the dimensions of the torque tube, i.e. length, inner diameter, and thickness. The objectives are to minimize cooling time and maximize rigidity. The exogenous parameters outside of the designer’s control include the required actuation stroke and aerodynamic forces. Results show the effects of parameters on the objective tradeoffs and demonstrate how an engineer can choose an optimal solution once the parameter values are known.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81741013","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}
María Guadalupe Orozco Sandoval, Moisés Hinojosa Rivera
The continuous reuse of powder in powder bed additive manufacturing techniques is a common practice, however, research focused on morphological changes in the powder as reuse cycles accumulate is relatively scarce, especially if we consider that the quality of the powder is fundamental to obtain components that meet the requirements of demanding industries such as aeronautics, automotive and medical. The continuous reuses of powder offer two important advantages which are reducing manufacturing costs and waste, both fundamental to the continuity of companies. The repercussions of uncontrolled reuse of powder without understanding the impact on final parts is a growing problem for a common practice. The present study focuses on the morphological changes in the particles of reused powder in five cycles of AlSi10Mg and the resulting effects on the components manufactured by the Selective Laser Melting (SLM) technique, varying manufacturing parameters defined as critical by the literature. Scanning Electron Microscopy (SEM) images of the powder were evaluated following the Zingg methodology, categorizing the particles into four shapes: sphere, disc, rod and blade. 80% of the virgin powder particles showed a spherical morphology, unlike the powder reused in five cycles, where this percentage is reduced by 8%. Elongated particles (blade and rod shape) showed an 11% increase in reused after five cycles. The variation in manufacturing parameters had an impact on the relative density of the components manufactured with reused powder, obtaining a maximum value of 94.5% and a minimum of 86%. The variation in the surface defects of the components was mostly influenced by the power of the laser, the scanning speed and the location of the component in the powder bed, where the sample set with the highest percentage of surface defects was where a laser power of 200 W and a scanning speed of 1000 mm/s and the gas flow was lower due to its location in the powder bed. The results allowed to establish the critical manufacturing parameters for components manufactured with reused powder in five cycles of AlSi10Mg; however, the accumulation of reuse cycles requires further investigation.
{"title":"Effect of Morphological Changes in Reused AlSi10Mg Powder on the Formation of Defects in Components Manufactured by SLM","authors":"María Guadalupe Orozco Sandoval, Moisés Hinojosa Rivera","doi":"10.1115/imece2021-72226","DOIUrl":"https://doi.org/10.1115/imece2021-72226","url":null,"abstract":"\u0000 The continuous reuse of powder in powder bed additive manufacturing techniques is a common practice, however, research focused on morphological changes in the powder as reuse cycles accumulate is relatively scarce, especially if we consider that the quality of the powder is fundamental to obtain components that meet the requirements of demanding industries such as aeronautics, automotive and medical. The continuous reuses of powder offer two important advantages which are reducing manufacturing costs and waste, both fundamental to the continuity of companies. The repercussions of uncontrolled reuse of powder without understanding the impact on final parts is a growing problem for a common practice. The present study focuses on the morphological changes in the particles of reused powder in five cycles of AlSi10Mg and the resulting effects on the components manufactured by the Selective Laser Melting (SLM) technique, varying manufacturing parameters defined as critical by the literature. Scanning Electron Microscopy (SEM) images of the powder were evaluated following the Zingg methodology, categorizing the particles into four shapes: sphere, disc, rod and blade. 80% of the virgin powder particles showed a spherical morphology, unlike the powder reused in five cycles, where this percentage is reduced by 8%. Elongated particles (blade and rod shape) showed an 11% increase in reused after five cycles. The variation in manufacturing parameters had an impact on the relative density of the components manufactured with reused powder, obtaining a maximum value of 94.5% and a minimum of 86%. The variation in the surface defects of the components was mostly influenced by the power of the laser, the scanning speed and the location of the component in the powder bed, where the sample set with the highest percentage of surface defects was where a laser power of 200 W and a scanning speed of 1000 mm/s and the gas flow was lower due to its location in the powder bed. The results allowed to establish the critical manufacturing parameters for components manufactured with reused powder in five cycles of AlSi10Mg; however, the accumulation of reuse cycles requires further investigation.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83648202","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}
J. Pang, Hong Guo, Juan Manuel Vázquez Martínez, J. Salguero, Patricia Iglesias Victoria
Laser micro-texturing treatment has been proved as an efficient way to improve tribological properties of metal alloys. Meanwhile, ionic liquids also show great potential as novel lubricant additives to increase the durability of contacting components and decrease the energy loss during tribological process. This study investigated the influence of the laser micro texturing surfaces on the tribological performance of titanium alloy Ti6Al4V under different lubricant conditions. In this research, two sets of dimple-textured surfaces created by different laser parameters, energy density and area density, were fabricated on Ti6Al4V. Polyalphaolefin (PAO) 40 and 1 wt.% 2-hydroxyethylammonium 2-ethylhexanoate (Eet) used as additive to PAO 40 were designed as lubricants during the sliding tests. First, the geometrical properties of laser micro-textures on the surfaces were characterized. The wetting behaviors of different lubricants on textured surfaces were then examined based on contact angle measurement. All the frictional tests were carried out on the ball-on-flat reciprocating tribometer under the same working conditions. Lastly, the surface morphology of the wear tracks on Ti6Al4V and tungsten carbide balls and their wear mechanisms were evaluated by using the optical microscope, scanning electron microscope, and energy-dispersive X-ray spectroscopy. The results exhibit the laser micro-textures have a positive effect on improving the tribological performance of Ti6Al4V. Meanwhile, the use of Eet as the lubricant additive to PAO 40 can facilitate the formation of the tribo-layer, which enhances the tribological behavior of laser micro-texturing Ti6Al4V surfaces.
{"title":"The Evaluation of Tribological Performance of Laser Micro-Texturing Ti6Al4V Under Lubrication With Protic Ionic Liquid","authors":"J. Pang, Hong Guo, Juan Manuel Vázquez Martínez, J. Salguero, Patricia Iglesias Victoria","doi":"10.1115/imece2021-69155","DOIUrl":"https://doi.org/10.1115/imece2021-69155","url":null,"abstract":"\u0000 Laser micro-texturing treatment has been proved as an efficient way to improve tribological properties of metal alloys. Meanwhile, ionic liquids also show great potential as novel lubricant additives to increase the durability of contacting components and decrease the energy loss during tribological process. This study investigated the influence of the laser micro texturing surfaces on the tribological performance of titanium alloy Ti6Al4V under different lubricant conditions. In this research, two sets of dimple-textured surfaces created by different laser parameters, energy density and area density, were fabricated on Ti6Al4V. Polyalphaolefin (PAO) 40 and 1 wt.% 2-hydroxyethylammonium 2-ethylhexanoate (Eet) used as additive to PAO 40 were designed as lubricants during the sliding tests. First, the geometrical properties of laser micro-textures on the surfaces were characterized. The wetting behaviors of different lubricants on textured surfaces were then examined based on contact angle measurement. All the frictional tests were carried out on the ball-on-flat reciprocating tribometer under the same working conditions. Lastly, the surface morphology of the wear tracks on Ti6Al4V and tungsten carbide balls and their wear mechanisms were evaluated by using the optical microscope, scanning electron microscope, and energy-dispersive X-ray spectroscopy. The results exhibit the laser micro-textures have a positive effect on improving the tribological performance of Ti6Al4V. Meanwhile, the use of Eet as the lubricant additive to PAO 40 can facilitate the formation of the tribo-layer, which enhances the tribological behavior of laser micro-texturing Ti6Al4V surfaces.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72761597","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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