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Articles 511 - 540 of 4850

Full-Text Articles in Engineering

Long-Term Modulus Of Microcracked Cement-Treated Base Layers, Patrick Matthew Mcdivitt Apr 2023

Long-Term Modulus Of Microcracked Cement-Treated Base Layers, Patrick Matthew Mcdivitt

Theses and Dissertations

The objective of this research was to measure and analyze the long-term modulus values of cement-treated base (CTB) layers constructed in Utah using microcracking. Because modulus values of pavement layers are among the most influential inputs affecting mechanistic-empirical pavement design, obtaining reasonable estimates of modulus values is critical. Testing was performed with a portable falling-weight deflectometer, also called a lightweight deflectometer, and modulus values were backcalculated with the computer program BAKFAA. Testing occurred at five asphalt pavement sites in northern Utah, where reconstruction with full-depth reclamation and cement stabilization, in the form of cement slurry, was performed approximately 2 to …

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Validation And Development Of Top-Down Illumination For Optofluidic Biosensors, Matthew Marley Hamblin Apr 2023

Validation And Development Of Top-Down Illumination For Optofluidic Biosensors, Matthew Marley Hamblin

Theses and Dissertations

Lab-on-a-chip devices are changing the way that medical testing is performed by allowing rapid testing with small samples. Optofluidic biosensors are a type of lab-on-a-chip device that use light excitation on a fluid sample. One such application of an optofluidic biosensor is a device that can detect antibiotic resistant bacteria by combining DNA from a sample with fluorescent beads, flowing that sample through a hollow channel, and shining laser light on the channel. If the bacteria tested for is present, the fluorescent beads will give off photons that can be detected as a positive signal. The main method for illumination …

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Large-Scale Testing Of Lightweight Cellular Concrete Backfill For Sliver-Fill Mse Wall Configurations, Meghann Dee Morgan Apr 2023

Large-Scale Testing Of Lightweight Cellular Concrete Backfill For Sliver-Fill Mse Wall Configurations, Meghann Dee Morgan

Theses and Dissertations

Lightweight cellular concrete (LCC) is an aerated or foamed concrete where 25-80% of the concrete matrix consists of air voids. The high volume of air voids reduces the strength but significantly decreases the weight of the material, which has made it an attractive alternative to soil for retaining structure backfills. Though the use of LCC has increased, little research has been performed on the large-scale behavior of retaining structures containing LCC as backfill. This research test attempts to fill knowledge gaps found with regard to the use of LCC in a mechanically stabilized earth (MSE) wall with a trapezoidal or …

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Large Eddy Simulation For Empirical Modeling Of The Wake Of Three Urban Air Mobility Vehicles, Denis-Gabriel Caprace, Andrew Ning Apr 2023

Large Eddy Simulation For Empirical Modeling Of The Wake Of Three Urban Air Mobility Vehicles, Denis-Gabriel Caprace, Andrew Ning

Faculty Publications

Recent advances in urban air mobility have driven the development of many new VTOL concepts. These vehicles often feature original designs departing from the conventional helicopter configuration. Due to their novelty, the characteristics of the super-vortices forming in the wake of such aircraft are unknown. However, these vortices may endanger any other vehicle evolving in their close proximity, owing to potentially large induced velocities. Therefore, improved knowledge about the wakes of VTOL vehicles is needed to guarantee safe urban air mobility operations. In this work, we study the wake of three VTOL aircraft in cruise by means of large eddy …

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Analyzing Online Media Platforms For Hacktivist Group Organization And Proliferation, Quincy Taylor Mar 2023

Analyzing Online Media Platforms For Hacktivist Group Organization And Proliferation, Quincy Taylor

Undergraduate Honors Theses

The anonymity and lack of censorship online provides the perfect environment for hacker activists to pursue social change. The expansive reach and democratic access to social media has empowered groups to organize and develop messaging to specifically fit an online audience. As social media become ubiquitous, the reputation and use of messaging application have become mainstream. Due to a self-professed focus on privacy, platforms like Telegram have become the norm for hosting the hacktivist communities. The purpose of this research was to understand the features in Telegram messages that correlate with the most engagement from their audience. As expected, the …

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Creating A Homophone-Based Chinese Language Censorship Evasion Tool, Emily Quan Mar 2023

Creating A Homophone-Based Chinese Language Censorship Evasion Tool, Emily Quan

Undergraduate Honors Theses

As the scope of Chinese language censorship expands, individuals will seek to bypass such censorship efforts. One of the most prevalent techniques in such censorship is automated keyword filtering. This research focuses on building a command-line tool that can bypass automated keyword filters for both traditional and simplified Chinese characters using a two-part approach. The first part involves detecting sensitive words in user-inputted text by using phrase matching techniques to identify character strings that have been censored in the past. The second part centers around generating possible obfuscated homonym alternatives. The tool relies on a compiled list of banned and …

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Simulations Of Morphology Control Of Self-Assembled Amphiphilic Surfactants, Qinyu Zhu, Douglas R. Tree Mar 2023

Simulations Of Morphology Control Of Self-Assembled Amphiphilic Surfactants, Qinyu Zhu, Douglas R. Tree

Faculty Publications

One of the grand challenges of amphiphilic self-assembly is the design of ordered structures whose morphology or shape can be explicitly and dynamically controlled by adjusting the properties of the amphiphiles or their surroundings. Such a capacity would enable researchers to create synthetic systems with functionality that meets or exceeds biological cells, and provide a robust platform for a broad range of engineering applications such as artificial tissues, drug delivery, and separation membranes. Despite significant progress, important fundamental questions remain unanswered, due in part to the limited resolution and the restricted parameter spaces that are readily accessible in experiments. Computational …

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Simulations Of Morphology Control Of Self-Assembled Amphiphilic Surfactants, Qinyu Zhu, Douglas R. Tree Mar 2023

Simulations Of Morphology Control Of Self-Assembled Amphiphilic Surfactants, Qinyu Zhu, Douglas R. Tree

Faculty Publications

One of the grand challenges of amphiphilic self-assembly is the design of ordered structures whose morphology or shape can be explicitly and dynamically controlled by adjusting the properties of the amphiphiles or their surroundings. Such a capacity would enable researchers to create synthetic systems with functionality that meets or exceeds biological cells, and provide a robust platform for a broad range of engineering applications such as artificial tissues, drug delivery, and separation membranes. Despite significant progress, important fundamental questions remain unanswered, due in part to the limited resolution and the restricted parameter spaces that are readily accessible in experiments. Computational …

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Control Education For Societal-Scale Challenges: A Community Roadmap, John Anthony Rossiter, Christos G. Cassandras, João Hespanha, Sebastian Dormido, Luis De La Torre, Gireeja Ranade, Antonio Visioli, John Hedengren, Richard M. Murray, Panos Antsaklis, Francoise Lamnabhi-Lagarrigue, Thomas Parisini Mar 2023

Control Education For Societal-Scale Challenges: A Community Roadmap, John Anthony Rossiter, Christos G. Cassandras, João Hespanha, Sebastian Dormido, Luis De La Torre, Gireeja Ranade, Antonio Visioli, John Hedengren, Richard M. Murray, Panos Antsaklis, Francoise Lamnabhi-Lagarrigue, Thomas Parisini

Faculty Publications

This article focuses on extending, disseminating and interpreting the findings of an IEEE Control Systems Society working group looking at the role of control theory and engineering in solving some of the many current and future societal challenges. The findings are interpreted in a manner designed to give focus and direction to both future education and research work in the general control theory and engineering arena, interpreted in the broadest sense. The paper is intended to promote discussion in the community and also provide a useful starting point for colleagues wishing to re-imagine the design and delivery of control-related topics …

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Concentrating E. Coli At Initial Low Concentrations By Centrifugation With Phosphate Buffered Saline, Plasma, And Simulated Blood Suspensions, Sarah Williams Mar 2023

Concentrating E. Coli At Initial Low Concentrations By Centrifugation With Phosphate Buffered Saline, Plasma, And Simulated Blood Suspensions, Sarah Williams

Undergraduate Honors Theses

The rapid diagnosis of blood stream infections (BSIs) is limited by the low concentration of bacteria in the blood. Currently, culturing of blood samples is used to increase the concentration of bacteria before the type of bacteria and the best antibiotic to treat the infection can be identified. However, the culturing of blood samples takes tens of hours, and therefore concentrating the bacteria from blood without growth will allow for quicker analysis and is crucial to saving lives. This thesis explored the means of concentrating E. coli suspensions in phosphate buffered saline (PBS), plasma, and simulated blood by centrifuging the …

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Large Deflection Analysis Of General Beams In Contact-Aided Compliant Mechanisms Using Chained Pseudo-Rigid-Body Model, Mohui Jin, Collin Ynchausti, Xianmin Zhang, Zhou Yang, Benliang Zhu, Larry L. Howell Mar 2023

Large Deflection Analysis Of General Beams In Contact-Aided Compliant Mechanisms Using Chained Pseudo-Rigid-Body Model, Mohui Jin, Collin Ynchausti, Xianmin Zhang, Zhou Yang, Benliang Zhu, Larry L. Howell

Faculty Publications

The nonlinear analysis and design of contact-aided compliant mechanisms (CCMs) are challenging. This paper presents a nonlinear method for analyzing the deformation of general beams that contact rigid surfaces in CCMs. The large deflection of the general beam is modeled by using the chained pseudo-rigid-body model. A geometry constraint from the contact surface is developed to constrain the beam’s deformed configuration. The contact analysis problem is formulated based on the principle of minimum potential energy and solved using an optimization algorithm. Besides, a novel technique based on the principle of work and energy is proposed calculate the reaction force/moment of …

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A Model For Multi-Input Mechanical Advantage In Origami-Based Mechanisms, Jared Butler, Adam Shrager, Timothy Simpson, Landen Bowen, Mary Frecker, Robert Lang, Eric Wilcox, Paris Von Lockette, Larry L. Howell, Spencer P. Magleby Mar 2023

A Model For Multi-Input Mechanical Advantage In Origami-Based Mechanisms, Jared Butler, Adam Shrager, Timothy Simpson, Landen Bowen, Mary Frecker, Robert Lang, Eric Wilcox, Paris Von Lockette, Larry L. Howell, Spencer P. Magleby

Faculty Publications

Mechanical advantage is traditionally defined for single input and single-output rigid-body mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origami-based mechanisms are capable of offering unique solutions to engi neering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection …

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Developable Mechanisms On Regular Cylindrical Surfaces, Jacob R. Greenwood, Spencer P. Magleby, Larry L. Howell Mar 2023

Developable Mechanisms On Regular Cylindrical Surfaces, Jacob R. Greenwood, Spencer P. Magleby, Larry L. Howell

Faculty Publications

Developable mechanisms can provide high functionality and compact stowability. This paper presents engineering models to aid in the design of cylindrical developable mechanisms. These models take into account the added spatial restrictions imposed by the developable surface. Equations are provided for the kinematic analysis of cylindrical developable mechanisms. A new classification for developable mechanisms is also presented (intramobile, extramobile, and transmobile) and two graphical methods are provided for determining this clas sification for single-DOF planar cylindrical developable mechanisms. Characteristics specific to four-bar cylindrical developable mechanisms are also discussed.

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Sources Of Atmospheric Dust Deposition On Utah Lake, Justin Telfer Mar 2023

Sources Of Atmospheric Dust Deposition On Utah Lake, Justin Telfer

Theses and Dissertations

Atmospheric deposition (AD) is a significant source of nutrient loading to waterbodies around the world. However, the sources and loading rates are poorly understood for major waterbodies and even less understood for local waterbodies. Utah Lake is a eutrophic lake located in central Utah, USA, and has high nutrient levels. Recent research has identified AD as significant sources for nutrient loading to the lake to better understand the dust AD sources, we sampled suspected source locations and collected deposition samples around the lake. We analyzed these samples using Inductively Coupled Plasma (ICP) for 25 metals to characterize their elemental fingerprints. …

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Nutrient Loadings To Utah Lake From Bulk Atmospheric Deposition, Mitchell Matthew Brown Mar 2023

Nutrient Loadings To Utah Lake From Bulk Atmospheric Deposition, Mitchell Matthew Brown

Theses and Dissertations

Atmospheric deposition is a marginally understood source of nutrient loadings to waterbodies. Atmospheric deposition occurs via wet (rain, snow) and dry (gaseous and particulate transport) pathways. Bulk atmospheric deposition is defined as the total deposition from both wet and dry pathways. Utah Lake is a shallow eutrophic freshwater lake located in central Utah, USA. Recent studies have shown atmospheric deposition to be a significant contributor to the nutrient budget of Utah Lake. This study presents the analysis using three different methods of six years' worth of wet atmospheric deposition samples from nine locations around the lake, though these samples do …

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Sustainably Providing Accurate Local River Discharge Data With Global Hydrologic Modeling And Bias Corrections, Riley Chad Hales Mar 2023

Sustainably Providing Accurate Local River Discharge Data With Global Hydrologic Modeling And Bias Corrections, Riley Chad Hales

Theses and Dissertations

The Global Water Sustainability Initiative of the Group of Earth Observations (GEOGloWS) supported an initiative to develop a global hydrologic model. The purpose of the modeling initiative is to build a high-quality model using the best available datasets and modeling methods with the primary emphasis on accessibility of the model. The goal is to make the model a sustainable source of river discharge information to supplement the capacity of those countries without the local capacity to maintain sufficient gauge networks and local modeling capabilities and cyberinfrastructure. Past research developed a modeling approach and piloted implementations and data and visualization services …

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Kinetostatic And Dynamic Modeling Of Flexure-Based Compliant Mechanisms: A Survey, Mingxiang Ling, Larry L. Howell, Junyi Cao, Guimin Chen Mar 2023

Kinetostatic And Dynamic Modeling Of Flexure-Based Compliant Mechanisms: A Survey, Mingxiang Ling, Larry L. Howell, Junyi Cao, Guimin Chen

Faculty Publications

Flexure-based compliant mechanisms are becoming increasingly promising in precision engineering, robotics and other applications due to the excellent advantages of no friction, no backlash, no wear, and minimal requirement of assembly. Because compliant mechanisms have inherent coupling of kinematic- mechanical behaviors with large deflections and/or complex serial-parallel configurations, the kinetostatic and dynamic analyses are challenging in comparison to their rigid-body counterparts. To address these challenges, a variety of techniques have been reported in a growing stream of publications. This paper surveys and compares the conceptual ideas, key advances, applicable scopes and open problems of the state-of-the-art kinetostatic and dynamic modeling …

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A Cprbm-Based Method For Large-Deflection Analysis Of Contact-Aided Compliant Mechanisms Considering Beam-To-Beam Contacts, Mohui Jin, Benliang Zhu, Jiasi Mo, Zhou Yang, Xianmin Zhang, Larry L. Howell Mar 2023

A Cprbm-Based Method For Large-Deflection Analysis Of Contact-Aided Compliant Mechanisms Considering Beam-To-Beam Contacts, Mohui Jin, Benliang Zhu, Jiasi Mo, Zhou Yang, Xianmin Zhang, Larry L. Howell

Faculty Publications

Contact-aided compliant mechanisms (CCMs) utilize contact to achieve enhanced functionality. The contact phenomenon of CCMs increases the difficulties of their analysis and design, especially when they exhibit beam-to-beam contact. Considering the particularity of CCMs analysis, which is more about the mechanisms’ deformation, this paper presents a numerical method to analyze the large deflection and stress of the CCMs considering beam-to-beam contacts. Based on our previous work on beam-to-rigid contact, the large deformation of general beams in CCMs is modeled by using the chained pseudo-rigid-body model (CPRBM). An approximation based on the geometric information of CPRBM is proposed in this paper …

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Design Of Regular 1d, 2d, And 3d Linkage-Based Tessellations, Alden D. Yellowhorse, Nathan Brown, Larry L. Howell Mar 2023

Design Of Regular 1d, 2d, And 3d Linkage-Based Tessellations, Alden D. Yellowhorse, Nathan Brown, Larry L. Howell

Faculty Publications

Linkage origami is one effective approach for addressing stiffness and accommodating panels of finite size in origami models and tessellations. However, successfully implementing linkage origami in tessellations can be challenging. In this work, multiple theorems are presented that provide criteria for designing origami units or cells that can be assembled into arbitrarily large tessellations. The application of these theorems is demonstrated through examples of tessellations in two and three dimensions.

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Developable Mechanisms On Right Conical Surfaces, Lance P. Hyatt, Spencer P. Magleby, Larry L. Howell Mar 2023

Developable Mechanisms On Right Conical Surfaces, Lance P. Hyatt, Spencer P. Magleby, Larry L. Howell

Faculty Publications

An approach for designing developable mechanisms on a conical surface is presented. By aligning the joint axes of spherical mechanisms to the ruling lines, the links can be created in a way that the mechanism conforms to a conical surface. Terminology is defined for mechanisms mapped onto a right cone. Models are developed to describe the motion of the mechanism with respect to the apex of the cone, and connections are made to cylindrical developable mechanisms using projected angles. The Loop Sum Method is presented as an approach to determine the geometry of the cone to which a given spherical …

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Deployable Convex Generalized Cylindrical Surfaces Using Torsional Joints, Todd G. Nelson, Jared T. Burton, Curtis G. Nelson, Luis M. Baldelomar Pinto, Zhicheng Deng, Larry L. Howell Mar 2023

Deployable Convex Generalized Cylindrical Surfaces Using Torsional Joints, Todd G. Nelson, Jared T. Burton, Curtis G. Nelson, Luis M. Baldelomar Pinto, Zhicheng Deng, Larry L. Howell

Faculty Publications

The ability to deploy a planar surface to a desired convex profile with a simple actuation can enhance foldable or morphing airfoils, deployable antennae and reflectors, and other applications where a specific profile geometry is desired from a planar sheet. A model using a system of rigid links joined by torsional springs of tailorable stiffness is employed to create an approximate curved surface when two opposing tip loads are applied. A system of equations describing the shape of the surface during deployment is developed. The physical implementation of the model uses compliant torsion bars as the torsion springs. A multidimensional …

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Membrane-Enhanced Lamina Emergent Torsional Joints For Surrogate Folds, Guimin Chen, Spencer P. Magleby, Larry L. Howell Mar 2023

Membrane-Enhanced Lamina Emergent Torsional Joints For Surrogate Folds, Guimin Chen, Spencer P. Magleby, Larry L. Howell

Faculty Publications

Lamina emergent compliant mechanisms (including origami-adapted compliant mechanisms) are mechanical devices that can be fabricated from a planar material (a lamina) and have motion that emerges out of the fabrication plane. Lamina emergent compliant mechanisms often exhibit undesirable parasitic motions due to the planar fabrication constraint. This work introduces a type of lamina emergent torsion (LET) joint that reduces parasitic motions of lamina emergent mechanisms (LEMs), and presents equations for modeling parasitic motion of LET joints. The membrane joint also makes possible one-way joints that can ensure origami-based mechanisms emerge from their flat state (a change point) into the desired …

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A Design Approach To Fully Compliant Multistable Mechanisms Employing A Single Bistable Mechanism, Yanjie Gou, Guimin Chen, Larry L. Howell Mar 2023

A Design Approach To Fully Compliant Multistable Mechanisms Employing A Single Bistable Mechanism, Yanjie Gou, Guimin Chen, Larry L. Howell

Faculty Publications

A fully compliant multistable mechanism is a monolithic structure that is capable of staying at multiple positions without power input, and has many applications including switches, valves, positioners. However, it is difficult to design such a mechanism because of the complexities of the multistable behavior, the practical stress limits and the buckling constraints. This paper discusses the design approach for fully compliant multistable mechanisms which employs a single bistable mechanism and several end-effectors connected in series. The force-displacement characteristics of the end-effectors are derived using the pseudo-rigid-body model. The design approach to the fully compliant multistable mechanism is provided to …

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Heat Set Creases In Polyethylene Terephthalate (Pet) Sheets To Enable Origami-Based Applications, Brandon Sargent, Nathan Brown, Brian D. Jensen, Spencer P. Magleby, William G. Pitt, Larry L. Howell Mar 2023

Heat Set Creases In Polyethylene Terephthalate (Pet) Sheets To Enable Origami-Based Applications, Brandon Sargent, Nathan Brown, Brian D. Jensen, Spencer P. Magleby, William G. Pitt, Larry L. Howell

Faculty Publications

Polyethylene terephthalate (PET) sheets show promise for application in origami-based engineering design. Origami-based engineering provides advantages that are not readily available in traditional engineering design methods. Several processing methods were examined to identify trends and determine the effect of processing of PET sheets on the crease properties of origami mechanisms in PET. Various annealing times, temperatures, and cooling rates were evaluated and data collected for over 1000 samples. It was determined that annealing temperature plays the largest role in crease response. An increase in the crystallinity of a PET sheet while in the folded state likely increases the force response …

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On The Modeling Of A Contact-Aided Cross-Axis Flexural Pivot, Pietro Bilancia, Giovanni Berselli, Spencer P. Magleby, Larry L. Howell Mar 2023

On The Modeling Of A Contact-Aided Cross-Axis Flexural Pivot, Pietro Bilancia, Giovanni Berselli, Spencer P. Magleby, Larry L. Howell

Faculty Publications

This paper reports the study of a planar Cross-Axis Flexural Pivot (CAFP) comprising an additional contact pair. The proposed device turns useful for applications requiring a revolute joint that behaves differently when deflecting clockwise/anti-clockwise. The presence of the contact pair reduces the free length of one flexures, resulting in a considerable increment of the overall joint stiffness. The pivot behaviour is investigated, for different load cases, via the ChainedBeam-Constraint Model (CBCM), namely an accurate method to be applied in large deflection problems. A framework comprising Matlab and ANSYS is developed for testing the CAFP performances in terms of rotational stiffness, …

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Rigidly Foldable Thick Origami Using Designed-Offset Linkages, Robert J. Lang, Nathan Brown, Brian Ignaut, Spencer P. Magleby, Larry L. Howell Mar 2023

Rigidly Foldable Thick Origami Using Designed-Offset Linkages, Robert J. Lang, Nathan Brown, Brian Ignaut, Spencer P. Magleby, Larry L. Howell

Faculty Publications

We present new families of thick origami mechanisms that achieve rigid foldability and parallel stacking of panels in the flat-folded state using linkages for some or all of the hinges between panels. A degree-four vertex results in a multi-loop eight-bar spatial mechanism that can be analyzed as separate linkages. The individual linkages are designed so that they introduce offsets perpendicular to the panels that are mutually compatible around each vertex. This family of mechanisms offers the unique combination of a planar unfolded state, parallel-stacked panels in the flat folded state, and kinematic single-degree-of-freedom motion from the flat- unfolded to the …

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An Origami-Based Medical Support System To Mitigate Flexible Shaft Buckling, Brandon Sargent, Jared Butler, Kendall Seymour, David Bailey, Brian D. Jensen, Spencer P. Magleby, Larry L. Howell Mar 2023

An Origami-Based Medical Support System To Mitigate Flexible Shaft Buckling, Brandon Sargent, Jared Butler, Kendall Seymour, David Bailey, Brian D. Jensen, Spencer P. Magleby, Larry L. Howell

Faculty Publications

This paper presents the development of an origami-inspired support system (the OriGuide) that enables the insertion of flexible instruments using medical robots. Varying parameters of a triangulated cylindrical origami pattern were combined to create an effective highly-compressible anti-buckling system that maintains a constant inner diameter for supporting an instrument and a constant outer diameter throughout actuation. The proposed origami pattern is composed of two repeated patterns: a bistable pattern to create support points to mitigate flexible shaft buckling and a monostable pattern to enable axial extension and compression of the support system. The origami-based portion of the device is combined …

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Limits Of Extramobile And Intramobile Motion Of Cylindrical Developable Mechanisms, Jared Butler, Larry L. Howell, Spencer P. Magleby, Jacob Greenwood Mar 2023

Limits Of Extramobile And Intramobile Motion Of Cylindrical Developable Mechanisms, Jared Butler, Larry L. Howell, Spencer P. Magleby, Jacob Greenwood

Faculty Publications

Mechanisms that can both deploy and provide motions to perform desired tasks offer a multifunctional advantage over traditional mechanisms. Developable mechanisms (DMs) are devices capable of conforming to a predetermined developable surface and deploying from that surface to achieve specific motions. This paper builds on the previously identified behaviors of extramobility and intramobility by introducing the terminology of extramobile and intramobile motion, which define the motion of developable mechanisms while interior and exterior to a developable surface. The limits of motion are identified using defined conditions. It is shown that the more difficult of these conditions to kinematically predict may …

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Analysis Of The Rigid Motion Of A Conical Developable Mechanism, Mckell Woodland, Michelle Hsiung, Erin L. Matheson, C Alex Safsten, Jacob Greenwood, Denise M. Halverson, Larry L. Howell Mar 2023

Analysis Of The Rigid Motion Of A Conical Developable Mechanism, Mckell Woodland, Michelle Hsiung, Erin L. Matheson, C Alex Safsten, Jacob Greenwood, Denise M. Halverson, Larry L. Howell

Faculty Publications

We demonstrate analytically that it is possible to construct a developable mechanism on a cone that has rigid motion. We solve for the paths of rigid motion and analyze the properties of this motion. In particular, we provide an analytical method for predicting the behavior of the mechanism with respect to the conical surface. Moreover, we observe that the conical developable mechanisms specified in this paper have motion paths that necessarily contain bifurcation points which lead to an unbounded array of motion paths in the parameterization plane.

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Load-Displacement Characterization In Three Degrees Of Freedom For General Let Arrays, Nathan A. Pehrson, Pietro Bilancia, Spencer P. Magleby, Larry L. Howell Mar 2023

Load-Displacement Characterization In Three Degrees Of Freedom For General Let Arrays, Nathan A. Pehrson, Pietro Bilancia, Spencer P. Magleby, Larry L. Howell

Faculty Publications

Lamina emergent torsion (LET) joints for use in origami-based applications enables folding of panels. Placing LET joints in series and parallel (formulating LET arrays) opens the design space to provide for tunable stiffness characteristics in other directions while maintaining the ability to fold. Analytical equations characterizing the elastic load-displacement for general serial-parallel formulations of LET arrays for three degrees of freedom are presented: rotation about the desired axis, in-plane rotation, and extension/compression. These equations enable the design of LET arrays for a variety of applications, including origami-based mechanisms. These general equations are verified using finite element analysis and, to show …

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