Nathan D. Spike, Akhil M Kurup, Derek J. Chopp, J. Bos, D. Robinette
Simulation is a critical step in the development of autonomous driving technologies, allowing engineers to test control algorithms, path planners, and other dynamic vehicle behaviors in a risk-free, low-cost environment. Under normal driving conditions representative of paved, most vehicle models are suitable for accurate prediction of vehicle motion. On low friction surfaces, basic vehicle models do not display the variability in vehicle response to steering input that is observed on real-world low friction surfaces such as clear ice. This work presents distribution parameters for a stochastic friction grid map for use in simulating vehicle behavior on icy surfaces. Simulation data from rapid double lane changes are compared with vehicle response to the same paths on an ice rink test course. Strong correlation between the simulation and test vehicle is achieved with validation performed using previously developed control and path planning methods.
{"title":"Improving Simulation to Hardware Correlation of Autonomous Vehicles Operating on Low Friction Surfaces","authors":"Nathan D. Spike, Akhil M Kurup, Derek J. Chopp, J. Bos, D. Robinette","doi":"10.1115/1.4056286","DOIUrl":"https://doi.org/10.1115/1.4056286","url":null,"abstract":"\u0000 Simulation is a critical step in the development of autonomous driving technologies, allowing engineers to test control algorithms, path planners, and other dynamic vehicle behaviors in a risk-free, low-cost environment. Under normal driving conditions representative of paved, most vehicle models are suitable for accurate prediction of vehicle motion. On low friction surfaces, basic vehicle models do not display the variability in vehicle response to steering input that is observed on real-world low friction surfaces such as clear ice. This work presents distribution parameters for a stochastic friction grid map for use in simulating vehicle behavior on icy surfaces. Simulation data from rapid double lane changes are compared with vehicle response to the same paths on an ice rink test course. Strong correlation between the simulation and test vehicle is achieved with validation performed using previously developed control and path planning methods.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84669160","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 effect of the grinding process for weld flash removal on the surface integrity of the welded joint has not been researched. The surface integrity of the welded joint is essential for the bandsaw blade life and to prevent any premature failure at the weld joint due to fatigue loading (a band saw blade undergoes mainly cyclic bending fatigue during its service). In this study, the effects of using different cutting fluid combinations on the grinding of weld flash in medium carbon alloy steel were carried out. The use of compressed air (CA) as a sustainable solution for grinding weld flash was explored. An experimental investigation of four different cutting fluid applications (dry/no cutting fluid, compressed air, minimum quantity lubricant using vegetable oil, and minimum quantity coolant using water-soluble oil) was carried out. The surface roughness, sub-surface residual stresses, and microhardness of the ground region were measured. This is a first-of-the-kind study on the effect of the flash removal process on the surface integrity of the welded joint. The results show that the surface integrity of the welded joint is significantly influenced by the cutting fluid application used during the grinding process of the flash. Dry grinding, the current industry standard for grinding weld flash in band saw blades, produced surface tensile residual stresses (24.82 MPa), lowest sub-surface microhardness (43.28 HRc), and the highest surface roughness (3.40 µm). In comparison, the air application had the highest surface compressive residual stresses (−289.57 MPa), highest sub-surface microhardness (48.67 HRc), and relatively low surface roughness (1.61 µm). This study provides the road map for selecting the cutting fluid application for grinding weld flash produced by the resistance welding process in the band sawing industry.
{"title":"Minimum Quantity Cutting Fluid Application for Grinding Weld Flash: Surface Integrity Evaluation","authors":"Nithin Rangasamy, Chanda Sekhar Rakurty, Zach Maurer","doi":"10.1115/1.4054948","DOIUrl":"https://doi.org/10.1115/1.4054948","url":null,"abstract":"\u0000 The effect of the grinding process for weld flash removal on the surface integrity of the welded joint has not been researched. The surface integrity of the welded joint is essential for the bandsaw blade life and to prevent any premature failure at the weld joint due to fatigue loading (a band saw blade undergoes mainly cyclic bending fatigue during its service). In this study, the effects of using different cutting fluid combinations on the grinding of weld flash in medium carbon alloy steel were carried out. The use of compressed air (CA) as a sustainable solution for grinding weld flash was explored. An experimental investigation of four different cutting fluid applications (dry/no cutting fluid, compressed air, minimum quantity lubricant using vegetable oil, and minimum quantity coolant using water-soluble oil) was carried out. The surface roughness, sub-surface residual stresses, and microhardness of the ground region were measured. This is a first-of-the-kind study on the effect of the flash removal process on the surface integrity of the welded joint. The results show that the surface integrity of the welded joint is significantly influenced by the cutting fluid application used during the grinding process of the flash. Dry grinding, the current industry standard for grinding weld flash in band saw blades, produced surface tensile residual stresses (24.82 MPa), lowest sub-surface microhardness (43.28 HRc), and the highest surface roughness (3.40 µm). In comparison, the air application had the highest surface compressive residual stresses (−289.57 MPa), highest sub-surface microhardness (48.67 HRc), and relatively low surface roughness (1.61 µm). This study provides the road map for selecting the cutting fluid application for grinding weld flash produced by the resistance welding process in the band sawing industry.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"2019 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87830181","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}
Understanding relationships between different products in a market system and predicting how changes in design impact their market position can be instrumental for companies to create better products. We propose a graph neural network-based method for modeling relationships between products, where nodes in a network represent products and edges represent their relationships. Our modeling enables a systematic way to predict the relationship links between unseen products for future years. When applied to a Chinese car market case study, our method based on an inductive graph neural network approach, GraphSAGE, yields double the link prediction performance compared to an existing network modeling method—exponential random graph model-based method for predicting the car co-consideration relationships. Our work also overcomes scalability and multiple data type-related limitations of the traditional network modeling methods by modeling a larger number of attributes, mixed categorical and numerical attributes, and unseen products. While a vanilla GraphSAGE requires a partial network to make predictions, we augment it with an “adjacency prediction model” to circumvent the limitation of needing neighborhood information. Finally, we demonstrate how insights obtained from a permutation-based interpretability analysis can help a manufacturer understand how design attributes impact the predictions of product relationships. Overall, this work provides a systematic data-driven method to predict the relationships between products in a complex network such as the car market.
{"title":"Product Competition Prediction in Engineering Design Using Graph Neural Networks","authors":"Faez Ahmed, Yaxin Cui, Yan Fu, Wei Chen","doi":"10.1115/1.4054299","DOIUrl":"https://doi.org/10.1115/1.4054299","url":null,"abstract":"\u0000 Understanding relationships between different products in a market system and predicting how changes in design impact their market position can be instrumental for companies to create better products. We propose a graph neural network-based method for modeling relationships between products, where nodes in a network represent products and edges represent their relationships. Our modeling enables a systematic way to predict the relationship links between unseen products for future years. When applied to a Chinese car market case study, our method based on an inductive graph neural network approach, GraphSAGE, yields double the link prediction performance compared to an existing network modeling method—exponential random graph model-based method for predicting the car co-consideration relationships. Our work also overcomes scalability and multiple data type-related limitations of the traditional network modeling methods by modeling a larger number of attributes, mixed categorical and numerical attributes, and unseen products. While a vanilla GraphSAGE requires a partial network to make predictions, we augment it with an “adjacency prediction model” to circumvent the limitation of needing neighborhood information. Finally, we demonstrate how insights obtained from a permutation-based interpretability analysis can help a manufacturer understand how design attributes impact the predictions of product relationships. Overall, this work provides a systematic data-driven method to predict the relationships between products in a complex network such as the car market.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87086165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper develops a mathematical model describing the motion through the air of an American football. The model is based on established equations used to describe spinning projectiles. While the equations are applicable to general motions, the emphasis of the paper is on the spiral pass and punt. Separate sections introduce formulas for the forces and moments understood to act on spun projectiles. The discussion of each force and moment includes an assessment of how well available experimental data characterizes the force or moment for an American football. For each force or moment, there is a description of how it affects the motion and trajectory. While the equations are valid for arbitrary motions, the available aerodynamic data is not. In parallel with the derivation of the nonlinear mathematical model, a linearized dynamics model is developed. The linearized model is used to help explain the behavior of the nonlinear model and to provide insight into the underlying physics. The linearized model is also used to derive a relationship between linear and angular velocity that ensures that the gyroscopic motion of a football is stable. The paper provides physical insights into what causes the apparent “wobble” of a spiral pass and what the character of the wobble says about the quality of the pass. Among the physical insights provided are the reason some passes have a rapid wobble and some slow, why a pass exhibits a lateral swerve, and why the Magnus effect may be neglected. The results are applicable to rugby footballs.
{"title":"Modeling the Dynamics of an American Football and the Stability Due to Spin","authors":"J. Dzielski, Mark Blackburn","doi":"10.1115/1.4054692","DOIUrl":"https://doi.org/10.1115/1.4054692","url":null,"abstract":"\u0000 This paper develops a mathematical model describing the motion through the air of an American football. The model is based on established equations used to describe spinning projectiles. While the equations are applicable to general motions, the emphasis of the paper is on the spiral pass and punt. Separate sections introduce formulas for the forces and moments understood to act on spun projectiles. The discussion of each force and moment includes an assessment of how well available experimental data characterizes the force or moment for an American football. For each force or moment, there is a description of how it affects the motion and trajectory. While the equations are valid for arbitrary motions, the available aerodynamic data is not. In parallel with the derivation of the nonlinear mathematical model, a linearized dynamics model is developed. The linearized model is used to help explain the behavior of the nonlinear model and to provide insight into the underlying physics. The linearized model is also used to derive a relationship between linear and angular velocity that ensures that the gyroscopic motion of a football is stable. The paper provides physical insights into what causes the apparent “wobble” of a spiral pass and what the character of the wobble says about the quality of the pass. Among the physical insights provided are the reason some passes have a rapid wobble and some slow, why a pass exhibits a lateral swerve, and why the Magnus effect may be neglected. The results are applicable to rugby footballs.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85099952","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}
G. Narendran, Amit Kumar, N. Gnanasekaran, D. Arumuga Perumal
Epilepsy is a common chronic neurological disorder characterized by abnormally excessive and synchronized brain cell activities causing seizures. For proper functioning of the brain, epilepsy should be diagnosed with existing treatments such as medication therapy, lorazepam, benzodiazepine drug intake, and surgery. However, 30–40% of people continue to have a seizure because of the available treatments. So, the focal brain cooling device (FBC) is a new alternative cooling method in which affected brain tissue is cooled to suppress unprovoked seizures. The present numerical study investigates the cooling effectiveness by adding three different structured titanium micro pin fins in the existing base model. A finite volume-based software fluent-15.0 is used to perform transient heat transfer analysis and flow hydrodynamics. The numerical results obtained show that the temperature distribution is found and more uniform and diamond-structured micro pin fin takes less than 7 min to reach below 15 °C, which is desirable to diminish the high-frequency and high-amplitude epileptic discharges.
{"title":"A Numerical Study on Microgap-Based Focal Brain Cooling Device to Mitigate Hotspot for the Treatment of Epileptic Seizure","authors":"G. Narendran, Amit Kumar, N. Gnanasekaran, D. Arumuga Perumal","doi":"10.1115/1.4055465","DOIUrl":"https://doi.org/10.1115/1.4055465","url":null,"abstract":"\u0000 Epilepsy is a common chronic neurological disorder characterized by abnormally excessive and synchronized brain cell activities causing seizures. For proper functioning of the brain, epilepsy should be diagnosed with existing treatments such as medication therapy, lorazepam, benzodiazepine drug intake, and surgery. However, 30–40% of people continue to have a seizure because of the available treatments. So, the focal brain cooling device (FBC) is a new alternative cooling method in which affected brain tissue is cooled to suppress unprovoked seizures. The present numerical study investigates the cooling effectiveness by adding three different structured titanium micro pin fins in the existing base model. A finite volume-based software fluent-15.0 is used to perform transient heat transfer analysis and flow hydrodynamics. The numerical results obtained show that the temperature distribution is found and more uniform and diamond-structured micro pin fin takes less than 7 min to reach below 15 °C, which is desirable to diminish the high-frequency and high-amplitude epileptic discharges.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86880411","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}
C. Rajendran, R. Ben Ruben, P. Ashokavarthanan, K. Mallieswaran
The corrosion-resistant and strength-to-weight ratios are the primary factors in high-strength aluminum alloy. Hence, the AA2024 alloy is a possible candidate in the critical structural fabrication industry. The traditional joining method is ineffective for welding aluminum alloys. Higher melting point and temperature variations cause alloy isolation; porosity and hot cracking are caused by melting point variations. As a result, to fabricate joints, a light heat source laser beam was used. The weaker area of most fusion-welded joints was the heat-affected zone (HAZ). The post-weld heat treatment was used at HAZ to improve the properties. According to the experimental findings, the joint welded with solution treatment and artificial aging had a maximum tensile strength of 358 MPa. Re-precipitation of precipitates may accomplish in HAZ.
{"title":"Identifying the Effect of PWHT on Strength of Laser Beam Welding Joints of AA2024 Aluminum Alloy","authors":"C. Rajendran, R. Ben Ruben, P. Ashokavarthanan, K. Mallieswaran","doi":"10.1115/1.4053496","DOIUrl":"https://doi.org/10.1115/1.4053496","url":null,"abstract":"\u0000 The corrosion-resistant and strength-to-weight ratios are the primary factors in high-strength aluminum alloy. Hence, the AA2024 alloy is a possible candidate in the critical structural fabrication industry. The traditional joining method is ineffective for welding aluminum alloys. Higher melting point and temperature variations cause alloy isolation; porosity and hot cracking are caused by melting point variations. As a result, to fabricate joints, a light heat source laser beam was used. The weaker area of most fusion-welded joints was the heat-affected zone (HAZ). The post-weld heat treatment was used at HAZ to improve the properties. According to the experimental findings, the joint welded with solution treatment and artificial aging had a maximum tensile strength of 358 MPa. Re-precipitation of precipitates may accomplish in HAZ.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86893777","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}
Since the events at the Fukushima–Daiichi nuclear power plant, there has been increased interest in developing accident tolerant fuel (ATF) to avoid accidents for light water reactors where Uranium-Silicide-based fuel has an excellent field to minimize the hydrogen hazards. Similarly, steel cladding is at the center of attraction for researchers nowadays. In this research, the feasibility of using Uranium-Silicides (i.e., U3Si, U3Si2, and U3Si5) combined with different types of austenitic steel (i.e., AISI) was investigated to improve the safety performance. A three-dimensional (3D) computational fluid dynamics (CFD)-coded star ccm+ model was used to assess heat transfer performance in the hexagonal fuel assembly of a supercritical water-cooled reactor VVER-1200. Utilizing the computational environment of star ccm+, the test analysis was conducted for a portion of fuel height using the realizable K-Epsilon Two-Layer Wall turbulence model. This analysis showed that the combination of U3Si2 fuel with AISI-348 cladding got superiority over other ATF-AISI fuel-claddings assemblies to use in the reactor core of VVER-1200 because of their lower central fuel temperature value with good mechanical and thermal advantages. This work also derived an empirical heat transfer coefficient equation to guide the relevant future investigations on the thermal analysis of the core.
{"title":"Influence of Accident-Tolerant Fuel With Steel Cladding for Sustainable Heat Transfer in the Reactor Core of VVER-1200","authors":"MD Tanzib Ehsan Sanglap, Sazidur Rahman Shahriar","doi":"10.1115/1.4054476","DOIUrl":"https://doi.org/10.1115/1.4054476","url":null,"abstract":"\u0000 Since the events at the Fukushima–Daiichi nuclear power plant, there has been increased interest in developing accident tolerant fuel (ATF) to avoid accidents for light water reactors where Uranium-Silicide-based fuel has an excellent field to minimize the hydrogen hazards. Similarly, steel cladding is at the center of attraction for researchers nowadays. In this research, the feasibility of using Uranium-Silicides (i.e., U3Si, U3Si2, and U3Si5) combined with different types of austenitic steel (i.e., AISI) was investigated to improve the safety performance. A three-dimensional (3D) computational fluid dynamics (CFD)-coded star ccm+ model was used to assess heat transfer performance in the hexagonal fuel assembly of a supercritical water-cooled reactor VVER-1200. Utilizing the computational environment of star ccm+, the test analysis was conducted for a portion of fuel height using the realizable K-Epsilon Two-Layer Wall turbulence model. This analysis showed that the combination of U3Si2 fuel with AISI-348 cladding got superiority over other ATF-AISI fuel-claddings assemblies to use in the reactor core of VVER-1200 because of their lower central fuel temperature value with good mechanical and thermal advantages. This work also derived an empirical heat transfer coefficient equation to guide the relevant future investigations on the thermal analysis of the core.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"305 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77364003","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}
Zilin Jiang, Shuheng Liao, A. Slocum, D. Leem, K. Ehmann, Jian Cao
Incremental sheet forming (ISF) offers great flexibility in producing complex sheet parts as compared with conventional sheet forming processes where part-specific die sets are required to form a product. While there are many potential applications of ISF in various industries, toolpath planning for multifeature parts remains a leading challenge hindering the wide adoption of ISF. In this study, a criterion based on the gradient of the target surface was established for determining the appropriate feature forming sequence. Based on the analysis of the gradients of the surface, multifeature geometries were separated into two categories: “plane-referenced” and “surface-referenced.” Experimental investigations of forming a multifeature air intake as an example were carried out to demonstrate the proposed criterion and feature forming sequence. The results show that the choice of the optimal sequence depends on the type of geometry formed. The proposed criterion extends existing toolpath strategies for relatively regular geometries, where features are formed from flat or inclined bases to more complex geometries with features on a curved basis. This work will be of interest to both design and manufacturing communities.
{"title":"Toolpath Planning for Manufacturing of Complex Parts Through Incremental Sheet Forming","authors":"Zilin Jiang, Shuheng Liao, A. Slocum, D. Leem, K. Ehmann, Jian Cao","doi":"10.1115/1.4053751","DOIUrl":"https://doi.org/10.1115/1.4053751","url":null,"abstract":"\u0000 Incremental sheet forming (ISF) offers great flexibility in producing complex sheet parts as compared with conventional sheet forming processes where part-specific die sets are required to form a product. While there are many potential applications of ISF in various industries, toolpath planning for multifeature parts remains a leading challenge hindering the wide adoption of ISF. In this study, a criterion based on the gradient of the target surface was established for determining the appropriate feature forming sequence. Based on the analysis of the gradients of the surface, multifeature geometries were separated into two categories: “plane-referenced” and “surface-referenced.” Experimental investigations of forming a multifeature air intake as an example were carried out to demonstrate the proposed criterion and feature forming sequence. The results show that the choice of the optimal sequence depends on the type of geometry formed. The proposed criterion extends existing toolpath strategies for relatively regular geometries, where features are formed from flat or inclined bases to more complex geometries with features on a curved basis. This work will be of interest to both design and manufacturing communities.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88884112","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}
Curve geometry plays a fundamental role in many aspects of analytical and computational mechanics, particularly in developing new data-driven science (DDS) approaches. Furthermore, curvature and torsion of space curves serve as deformation measures that need to be properly interpreted, shedding light on the significance of relationship between differential-geometry curve framing methods and computational-mechanics motion description. Alternate space-curve framing methods were proposed to address the existence of Frenet frame at isolated zero-curvature points. In this paper, both mechanics and differential-geometry approaches are used to establish Frenet-frame continuity and the existence of Serret-Frenet equations at curvature-vanishing points for curves with arbitrary parameterization. Frenet–Euler angles, referred to for brevity as Frenet angles, are used to define curve geometry, with particular attention given to the definition of Frenet bank angle used to prove the existence of curve normal and binormal vectors at curvature-vanishing points. Solving curvature-singularity problem and using mechanics description based on Frenet angles contributes to successful development and computer implementation of new DDS approaches based on analysis of recorded motion trajectories (RMT). Centrifugal-inertia force is always in direction of curve normal vector, and in most applications, this force is continuous and approaches zero value as curve curvature approaches zero. Discontinuity in definition of Frenet frame can negatively impact the quality of numerical results that define RMT curves. The study also demonstrates that Frenet-frame curvature singularity can be solved without need for integrating curve torsion, which is not, in general, an exact differential.
{"title":"Curvature Singularity of Space Curves and Its Relationship to Computational Mechanics","authors":"A. Shabana","doi":"10.1115/1.4053339","DOIUrl":"https://doi.org/10.1115/1.4053339","url":null,"abstract":"\u0000 Curve geometry plays a fundamental role in many aspects of analytical and computational mechanics, particularly in developing new data-driven science (DDS) approaches. Furthermore, curvature and torsion of space curves serve as deformation measures that need to be properly interpreted, shedding light on the significance of relationship between differential-geometry curve framing methods and computational-mechanics motion description. Alternate space-curve framing methods were proposed to address the existence of Frenet frame at isolated zero-curvature points. In this paper, both mechanics and differential-geometry approaches are used to establish Frenet-frame continuity and the existence of Serret-Frenet equations at curvature-vanishing points for curves with arbitrary parameterization. Frenet–Euler angles, referred to for brevity as Frenet angles, are used to define curve geometry, with particular attention given to the definition of Frenet bank angle used to prove the existence of curve normal and binormal vectors at curvature-vanishing points. Solving curvature-singularity problem and using mechanics description based on Frenet angles contributes to successful development and computer implementation of new DDS approaches based on analysis of recorded motion trajectories (RMT). Centrifugal-inertia force is always in direction of curve normal vector, and in most applications, this force is continuous and approaches zero value as curve curvature approaches zero. Discontinuity in definition of Frenet frame can negatively impact the quality of numerical results that define RMT curves. The study also demonstrates that Frenet-frame curvature singularity can be solved without need for integrating curve torsion, which is not, in general, an exact differential.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82836509","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}
S. Kamrava, M. Tatari, Yustianto Tjiptowidjojo, H. Nayeb-Hashemi
Inflatable structures are commonly used in a variety of engineering applications such as robotics, space structures, medical devices, and automotive safety devices. However, inflation in these systems often requires a non-flexible external pressurized fluid source. Integration of the pressurized fluid source and the flexible construct sacrifices some of the main advantages of the soft structures such as overall flexibility of the system, weight, and cost of fabrication. In this paper, we introduce a novel design for self-inflating structure with embedded pressurizing module. The design is based on integrating a flexible dome with a cylinder. The pressure inside the cylinder is controlled by subjecting dome to a cyclic compression, causing air exchange between the dome and the cylinder. The performance of this design is fully validated through finite element simulations using fluid structure interactions as well as experimental investigations. The results show that a higher pressure is achieved by having smaller dome height. In addition to controlling internal pressure of the cylinder, the design can be used to control the stiffness of the flexible structure such as soft robotics through pressurization. An application of this conceptual device such as pressurizing a tire is presented. This device is integrated within a tire and tire rotation as well as load on the tire have been shown to pressurize the tire. The final pressure and time to achieve maximum pressure depend on the load to the axel of the tire and tire rotational speed, respectively.
{"title":"Design and Characterization of a Flexible Self-Inflating Mechanical Structure","authors":"S. Kamrava, M. Tatari, Yustianto Tjiptowidjojo, H. Nayeb-Hashemi","doi":"10.1115/1.4054953","DOIUrl":"https://doi.org/10.1115/1.4054953","url":null,"abstract":"\u0000 Inflatable structures are commonly used in a variety of engineering applications such as robotics, space structures, medical devices, and automotive safety devices. However, inflation in these systems often requires a non-flexible external pressurized fluid source. Integration of the pressurized fluid source and the flexible construct sacrifices some of the main advantages of the soft structures such as overall flexibility of the system, weight, and cost of fabrication. In this paper, we introduce a novel design for self-inflating structure with embedded pressurizing module. The design is based on integrating a flexible dome with a cylinder. The pressure inside the cylinder is controlled by subjecting dome to a cyclic compression, causing air exchange between the dome and the cylinder. The performance of this design is fully validated through finite element simulations using fluid structure interactions as well as experimental investigations. The results show that a higher pressure is achieved by having smaller dome height. In addition to controlling internal pressure of the cylinder, the design can be used to control the stiffness of the flexible structure such as soft robotics through pressurization. An application of this conceptual device such as pressurizing a tire is presented. This device is integrated within a tire and tire rotation as well as load on the tire have been shown to pressurize the tire. The final pressure and time to achieve maximum pressure depend on the load to the axel of the tire and tire rotational speed, respectively.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87730984","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}