Matching Items (90)

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Studies of the Mechanics of Origami Inspired Foam Structures

Description

This thesis examines the mechanical properties of an origami inspired structure and its equivalent cube counterpart to determine if this origami configuration is an effective load bearing and energy absorption structure. To test this, a folded paper model was created

This thesis examines the mechanical properties of an origami inspired structure and its equivalent cube counterpart to determine if this origami configuration is an effective load bearing and energy absorption structure. To test this, a folded paper model was created for visual realization and then 3D printed models were created to undergo compression testing using the Instron 4411. The data from testing was used to create stress-strain curves for each sample, which were then used to determine the maximum stress and toughness of each structure. The performance of these structures was also compared to other known material performance. The origami structure was found to outperform the equivalent cube in both maximum stress it could withstand before failure and toughness. These results are grounds for further research to be done to determine the validity of origami structures as viable alternatives to current material configurations.

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Created

Date Created
2018-05

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Explicit Dynamics Analysis of Collapsible Polymer-Carbon Lightweight Ammunition Package

Description

Structural assemblies for military applications must be guaranteed to withstand normal operating environments. Traditionally, experimental testing is performed on a prototype of the object to understand how it will behave under potential failure conditions. However, this process can be time-consuming

Structural assemblies for military applications must be guaranteed to withstand normal operating environments. Traditionally, experimental testing is performed on a prototype of the object to understand how it will behave under potential failure conditions. However, this process can be time-consuming and expensive, and it is often desired to have preliminary information to guide the design of the components. Consequently, a finite element analysis (FEA) can be performed using computational tools to approximate the failure behavior of the object before experiments are performed. This can provide information for a faster preliminary evaluation of the design, which very useful when implementing new technologies in the defense sector.
Currently, a new design for collapsible, lightweight ammunition package (LAP) has been proposed for military applications. The design employs rubber gaskets which enable the LAP to fold when it is empty, in addition to carbon fiber walls which decrease weight while increasing strength. To evaluate the new design, it is desired to perform a finite element analysis to simulate the behavior of the can under various drop impact conditions. Because the design includes complex joinery, which is often difficult to model, the purpose of this thesis project is to determine the most effective methodology to define the physical system using finite elements for impact simulations, and consequently perform the desired analysis for the LAP.

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Date Created
2020-05

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Mechanics of Origami Inspired Structures

Description

This research project will test the structural properties of a 3D printed origami inspired structure and compare them with a standard honeycomb structure. The models have equal face areas, model heights, and overall volume but wall thicknesses will be different.

This research project will test the structural properties of a 3D printed origami inspired structure and compare them with a standard honeycomb structure. The models have equal face areas, model heights, and overall volume but wall thicknesses will be different. Stress-deformation curves were developed from static loading testing. The area under these curves was used to calculate the toughness of the structures. These curves were analyzed to see which structures take more load and which deform more before fracture. Furthermore, graphs of the Stress-Strain plots were produced. Using 3-D printed parts in tough resin printed with a Stereolithography (SLA) printer, the origami inspired structure withstood a larger load, produced a larger toughness and deformed more before failure than the equivalent honeycomb structure.

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Created

Date Created
2018-05

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Origami Based Mechanical Metamaterials

Description

We describe mechanical metamaterials created by folding flat sheets in the tradition of origami, the art of paper folding, and study them in terms of their basic geometric and stiffness properties, as well as load bearing capability. A periodic Miura-ori

We describe mechanical metamaterials created by folding flat sheets in the tradition of origami, the art of paper folding, and study them in terms of their basic geometric and stiffness properties, as well as load bearing capability. A periodic Miura-ori pattern and a non-periodic Ron Resch pattern were studied. Unexceptional coexistence of positive and negative Poisson's ratio was reported for Miura-ori pattern, which are consistent with the interesting shear behavior and infinity bulk modulus of the same pattern. Unusually strong load bearing capability of the Ron Resch pattern was found and attributed to the unique way of folding. This work paves the way to the study of intriguing properties of origami structures as mechanical metamaterials.

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Date Created
2014-08-07

Kirigami-Based Stretchable Lithium-Ion Batteries

Description

We have produced stretchable lithium-ion batteries (LIBs) using the concept of kirigami, i.e., a combination of folding and cutting. The designated kirigami patterns have been discovered and implemented to achieve great stretchability (over 150%) to LIBs that are produced by

We have produced stretchable lithium-ion batteries (LIBs) using the concept of kirigami, i.e., a combination of folding and cutting. The designated kirigami patterns have been discovered and implemented to achieve great stretchability (over 150%) to LIBs that are produced by standardized battery manufacturing. It is shown that fracture due to cutting and folding is suppressed by plastic rolling, which provides kirigami LIBs excellent electrochemical and mechanical characteristics. The kirigami LIBs have demonstrated the capability to be integrated and power a smart watch, which may disruptively impact the field of wearable electronics by offering extra physical and functionality design spaces.

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Created

Date Created
2015-06-11

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Optimal Dimensions for Beam Power Harvester for Maximum Power Output

Description

In the last several years, there has been a significant growth in research in the field of power harvesting, the process of capturing the energy surrounding a system and converting it into usable electrical energy. This concept has received particular

In the last several years, there has been a significant growth in research in the field of power harvesting, the process of capturing the energy surrounding a system and converting it into usable electrical energy. This concept has received particular interest in recent years with the ever-increasing production of portable and wireless electronic devices. Many of these devices that are currently in production utilize electrochemical batteries as a power source, which while effective, maintain the drawback of having a finite energy supply, thus requiring periodic replacement. The concept of power harvesting, however, works to solve these issues through electronics that are designed to capture ambient energy surrounding them convert it into usable electronic energy. The use of power harvesting in energy scavenging devices allows for the possible development of devices that are self-powered and do not require their power sources to be replaced. Several models have been developed by Soldano et al [3] and Liao et al [2] that have been proven accurate at predicting the power output of a piezoelectric power harvester in a cantileaver beam configuration. The work in this paper will expand further on the model developed by Liao et al [2], and as its main goal will use a modified form of that model to predict the optimal dimensions for a beam power harvester to achieve the maximum power output possible. The model will be updated b replacing the mode shape function used to approximate the deflection of the beam with the true defletion, which is based on the complex wavenumber that incorporates the complex Young's modulus of the material used. Other changes to account for this replacement will also be presented, along with numerical results of the final model.

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Created

Date Created
2012-05

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Pyrrole-based poly(ionic liquids) as efficient stabilizers for formation of hollow MWCNT particles

Description

Poly(ionic liquid)s (PILs) with an intrinsically conducting pyrrole polymer (ICP) backbone were synthesized and utilized as novel dispersants of carbon nanotubes (CNTs) in various polar and nonpolar solvents. This is due to their highly tunable nature, in which the anions

Poly(ionic liquid)s (PILs) with an intrinsically conducting pyrrole polymer (ICP) backbone were synthesized and utilized as novel dispersants of carbon nanotubes (CNTs) in various polar and nonpolar solvents. This is due to their highly tunable nature, in which the anions can be easily exchanged to form PILs of varying polarity but with the same polycation. These CNT dispersions were exceedingly stable over many months, and with the addition of hexane, Pickering emulsions with the PIL-stabilized CNTs at the droplet interfaces were formed. Depending on the hydrophobicity of the PIL, hexane-in-water and hexane-in-acetonitrile emulsions were formed, the latter marking the first non-aqueous stabilized-CNT emulsions and corresponding CNT-in-acetonitrile dispersion, further advancing the processability of CNTs. The PIL-stabilized CNT Pickering emulsion droplets generated hollow conductive particles by subsequent drying of the emulsions. With the emulsion templating, the hollow shells can be used as a payload carrier, depending on the solubility of the payload in the droplet phase of the emulsion. This was demonstrated with silicon nanoparticles, which have limited solubility in aqueous environments, but great scientific interest due to their potential electrochemical applications. Overall, this work explored a new class of efficient PIL-ICP hybrid stabilizers with tunable hydrophobicity, offering extended stability of carbon nanotube dispersions with novel applications in hollow particle formation via Pickering emulsion templating and in placing payloads into the shells.

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Date Created
2015-12

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Ultra High Strain Sensing using an Optical Scanning Methodology

Description

A novel strain sensing procedure using an optical scanning methodology and diffraction grating is explored. The motivation behind this study is due to uneven thermal strain distribution across semiconductor chips that are composed of varying materials. Due to the unique

A novel strain sensing procedure using an optical scanning methodology and diffraction grating is explored. The motivation behind this study is due to uneven thermal strain distribution across semiconductor chips that are composed of varying materials. Due to the unique properties of the materials and the different coefficients of thermal expansion (CTE), one can expect the material that experiences the highest strain to be the most likely failure point of the chip. As such, there is a need for a strain sensing technique that offers a very high strain sensitivity, a high spatial resolution while simultaneously achieving a large field of view. This study goes through the optical setup as well as the evolution of the optical grating in an effort to improve the strain sensitivity of this setup.

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Date Created
2014-05

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Buckling Phenomenon in Pre-Stretched PDMS Substrates

Description

The data and results presented in this paper are part of a continuing effort to innovate and pioneer the future of engineering. The purpose of the following is to demonstrate the mechanical buckling characteristics in stiff thin film and soft

The data and results presented in this paper are part of a continuing effort to innovate and pioneer the future of engineering. The purpose of the following is to demonstrate the mechanical buckling characteristics in stiff thin film and soft substrate systems, and the importance of controlling them. In today's engineering research, wrinkling in systems in beginning to be viewed as a means for engineering innovation rather than failure. This research is important to further progress the possible applications the technology proposes, such as flexible electronics and tunable adhesives. This work utilizes a cost efficient and relatively easy method for generating and analyzing buckled systems. Ultra violate oxidation at ambient temperatures is exploited to create a stiff thin surface on rubber like polydimethylsiloxane, and couple with strain induction wrinkles are generated. Wrinkle characteristics such as amplitude, wavelengths and wetting properties were investigated. In simple cases, trends were confirmed that increased oxidation relates to increased buckle wavelengths, and increase in strain corresponds to a decrease in wavelength. Hierarchical buckles were produced in one-dimensional systems treated with a multi-step method; these were the first to be generated in the ASU labs. Unique topographic changes were produced in two-dimensional systems treated with the same method. Honeycomb or dome like structures were noted to occur, important as they undergo a different energy-reliving configuration compared to traditional parallel buckles. The information provided characterizes many aspects of the buckle phenomena and will allow for further inquiry into specific functions utilizing the technology to continue advancements in engineering.

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Date Created
2013-05