Mechanical Engineering Commons^™

Detection Of The Direction And Speed Of Motion Of Forces On The Surface Of A Compliant Tactile Sensor, Erik Engeberg, Morteza Vatani, Jae-Won Choi

Dr. Jae-Won Choi

A compliant tactile sensor (CTS) has been developed with two orthogonal layers of multi-walled carbon nanotubes (MWNTs) and polymer strips. This has enabled the detection of sliding motion along the surface of the sensor. This information is used to detect the motions of forces applied on the surface of the CTS. The speed of sliding motion in each direction can be updated with a resolution of 3mm in both of two perpendicular directions.

Arbitrary Photo-Patterning In Liquid Crystal Alignments Using Dmd Based Lithography System, Hao Wu, Hua-Chao Hu, Xiao-Wen Lin, Ge Zhu, Jae-Won Choi, Vladimir Chigrinov, Yan-Qing Lu

Dr. Jae-Won Choi

We propose and implement a technique for arbitrary pattern fabrication in liquid crystal (LC) alignments and local polarization control for light wavefront. A micro-lithography system with a digital micro-mirror device as dynamic mask forms arbitrary micro-images on photoalignment layers and further guides the LC molecule orientations. Besides normal phase gratings, more complex 2D patterns such as quasicrystal and checkerboard structures are demonstrated. To characterize the optical performances of the fabricated structures, the electro-optically tunable diffraction patterns and efficiencies are demonstrated in several 1D/2D phase gratings. Compared to other techniques, our method enables the arbitrary and instant manipulation of LC alignments …

Multi-Material Microstereolithography, Jae-Won Choi, Eric Macdonald, Ryan Wicker

Dr. Jae-Won Choi

We have previously described the development of a microstereolithography (µSL) system using a Digital Micromirror Device (DMD) for dynamic pattern generation and an ultraviolet (UV) lamp filtered at 365 nm for crosslinking a photoreactive polymer solution. The µSL system was designed with x–y resolution of approximately 2 µm and a vertical (z) resolution of approximately 1 µm (with practical build limitations on vertical resolution of approximately 30 µm due to limitations on controlling UV penetration in z). The developed µSL system is capable of producing real three-dimensional (3D) microstructures, which can be employed in applications …

Arbitrary Photopatterning In Liquid Crystal Alignments Using Dmd Based Lithography System, Hao Wu, Wei Hu, Xiao-Wen Lin, Ge Zhu, Jae-Won Choi, Vladimir Chigrinov, Yan-Qing Lu

Dr. Jae-Won Choi

We propose and implement a technique for arbitrary pattern fabrication in liquid crystal (LC) alignments and local polarization control for light wavefront. A micro-lithography system with a digital micro-mirror device as dynamic mask forms arbitrary micro-images on photoalignment layers and further guides the LC molecule orientations. Besides normal phase gratings, more complex 2D patterns such as quasicrystal and checkerboard structures are demonstrated. To characterize the optical performances of the fabricated structures, the electro-optically tunable diffraction patterns and efficiencies are demonstrated in several 1D/2D phase gratings. Compared to other techniques, our method enables the arbitrary and instant manipulation of LC alignments …

Direct-Write Stretchable Sensors Using Single-Walled Carbon Nanotube/Polymer Matrix, Morteza Vatani, Yangfen Lu, Kye-Shin Lee, Ho-Chan Kim, Jae-Won Choi

Dr. Jae-Won Choi

There have been increasing demands and interests in stretchable sensors with the development of flexible or stretchable conductive materials. These sensors can be used for detecting large strain, 3D deformation, and a free-form shape. In this work, a stretchable conductive sensor has been developed using single-walled carbon nanotubes (SWCNTs) and monofunctional acrylate monomers (cyclic trimethylolpropane formal acrylate and acrylate ester). The suggested sensors have been fabricated using a screw-driven microdispensing direct-write (DW) technology. To demonstrate the capabilities of the DW system, effects of dispensing parameters such as the feed rate and material flow rate on created line widths were investigated. …

Hybrid Additive Manufacturing Of 3d Compliant Tactile Sensors, Morteza Vatani, Erik Engeberg, Jae-Won Choi

Dr. Jae-Won Choi

A resistance based conformal, compliant multi-layer tactile sensor was designed and built layer by layer using a hybrid manufacturing process. A highly stretchable, photocurable, piezoresistive sensing material was deposited on a conformal, soft molded structure using a direct printing device. The principle of the sensor is based on detecting the changes in resistance as it is deformed. The fabricated tactile sensor consists of two layers of sensing elements within the 3D skin structure where the sensing elements in the top layer are orthogonally placed atop the bottom layer. Due to the multiple layers of wires, the sensor can potentially detect …

Cord Load Characteristics In Bias And Belted-Bias Tires, Joseph Walter, George Hall

Dr. Joseph D. Walter

Two improved versions of a recently developed miniature force transducer were used to measure cord loads at the crown, shoulder, and sidewall of bias and belted-bias automobile tires under different testing conditions. As a transducer at a given location passes through the footprint, a “basic shape” for the cord force pattern is generated for straight ahead rolling and cornering. Factors such as wheel load, inflation pressure, obstacle impact, tire speed, rim width, and frictional properties of the tire-drum interface can affect the total force excursion and/or the base line value but do not affect the basic shape of the patterns. …

Energy Losses In Tires, Joseph Walter, F. Conant

Dr. Joseph D. Walter

Tire rotation is impeded by a drag force of 10 to 20 lb per 1000‐lb load in normal vehicle operation. The principal cause is hysteresis, which is a function of the viscoelastic properties of the rubber and cord components, the way these materials are used in the tire, and the way the tire is operated. The influence of material properties has been well documented, and many laboratory tests have been developed for their measurement. Of even greater importance to energy losses, however, is tire construction. This subject is developed by consideration of the forces and moments involved in tire operation …

Frictional Interaction Of Tire And Pavement, Joseph Walter

Dr. Joseph D. Walter

No abstract provided.

Interlaminar Shear Strain Measurements In Cord-Rubber Composites, A. Lou, Joseph Walter

Dr. Joseph D. Walter

The present work is an experimental study using an X-ray technique to measure directly the internal distribution of interlaminar shear deformations which occur during uniaxial extension of two-ply, cord-rubber, angle-ply laminates—both balanced and unbalanced. Significant interlaminar shear strains were developed between the two generally orthotropic layers of one-inch-wide specimens, which decreased almost linearly from a maximum at the edges to zero at the center line. These measurements and those as a function of cord angle were in good agreement with predictions obtained from various theories of laminated shear-flexible composites.

Surface Temperature Of Running Tires Using Infrared Scanning, F. Conant, Joseph Walter

Dr. Joseph D. Walter

An infrared line scanning system has been used to measure surface temperatures of automobile tires under operating conditions. A designed experiment was employed to demonstrate statistically the individual and interaction effects on tire temperature profiles of changes in tire speed, inflation pressure, and wheel load. These effects are different at different radial positions on a given tire and are quite dependent on tire construction, as illustrated by application to bias, belted-bias, and radial tires of comparable sizes.

Centrifugal Effects In Inflated, Rotating Bias-Ply Tires, Joseph Walter

Dr. Joseph D. Walter

An equation is derived which governs the dynamic equilibrium contour taken by an inflated and rotating, but otherwise unloaded, bias-ply tire. This equation, which is in the form of a hyperelliptic integral, is based on the membrane theory of shells and the netting analysis of composite materials. Results are obtained for the meridional geom etry of a typical two-ply automobile tire, which are in reasonable agreement with ex perimental measurements. This integral, which describes the dynamic equilibrium contour of the tire, is then used to obtain an algebraic cord load formula. The formula shows how the cord tension at any …

Pneumatic Tire, Alan Neville Gent, Joseph D. Walter

Dr. Joseph D. Walter

For many years, tire engineers relied on the monograph, 'Mechanics of Pneumatic Tires', for detailed information about the principles of tire design and use. Published originally by the National Bureau of Standards, U.S. Department of Commerce, in 1971, and a later (1981) edition by the National Highway Traffic Safety Administration (NHTSA), U.S. Department of Transportation, it has long been out of print. No textbook or monograph of comparable range and depth has appeared since. While many chapters of the two editions contain authoritative reviews that are still relevant today, they were prepared in an era when bias ply and belted-bias …

Cord—Rubber Tire Composites: Theory And Applications, Joseph Walter

Dr. Joseph D. Walter

The stiffness and strength behavior of the constituent cord and rubber components of the pneumatic tire have been studied in detail by investigators in the industry since the early days of tire production. For example, the effect of twist on the stress-strain properties of cotton tire cord and the reinforcing effect of carbon black on the modulus of natural rubber were well known phenomena many decades ago. Similarly, differences between the elastic and viscoelastic behavior of cord and rubber have been well documented since the 1940's. On the other hand, the material properties (specifically, the elastic constants) of the cord-rubber …

Radial Tire Cord-Rubber Composites, H. Patel, J. Turner, Joseph Walter

Dr. Joseph D. Walter

Experimental and theoretical results are presented in terms of the elements of the compliance matrix for the material properties which are needed to characterize a calendered ply of various cord-rubber composites commonly used in the body and belt of radial tires. It is shown that a single ply can be represented as a linear, elastic, homogeneous, orthotropic material to a level of accuracy sufficient for modeling inflated, but otherwise unloaded, radial tires. Cord load distributions in the body, belt, and turnup ply endings are predicted and plotted from the bead to the crown of inflated radial tires using principles of …

Interlaminar-Shear-Strain Measurements In Cord-Rubber Composites, A. Lou, Joseph Walter

Dr. Joseph D. Walter

The present work is an experimental study using an X-ray technique to measure directly the internal distribution of interlaminar-shear deformations which occur during uniaxial extension of two-ply, cord-rubber, angle-ply laminates—both balanced and unbalanced. Significant interlaminar-shear strains were developed between the two generally orthotropic layers of one-inch-wide specimens, which decreased almost linearly from a maximum at the edges to zero at the center line. These measurements, and those as a function of cord angle, were in good agreement with predictions obtained from various theories of laminated shear-flexible composites.

A Tirecord Tension Transducer, Joseph Walter

Dr. Joseph D. Walter

A transducer is described which can directly measure the cord tension at any point in an arbitrarily loaded tire. Cord force data obtained at the crown and in the sidewall for a typical two-ply automobile tire are presented for: (1) the inflation problem, (2) the static deflection problem, and (3) the rolling tire. Agreement between theory and experiment is good for the inflation problem, which is the only case where a cord load formula exists to allow comparison.

Approximate Expressions For The Elastic Constants Of Cord-Rubber Laminates, Joseph Walter, H. Patel

Dr. Joseph D. Walter

The relatively simple equations given herein for the four independent elastic constants of a single ply of cord and rubber and for the three independent elastic constants of a cord-rubber angle-ply laminate can be used to assess with sufficient accuracy for many purposes the effect of changes in constituent material properties and/or ply geometry on the stiffness characteristics of unidirectional, filamentary composites used in pneumatic tires.

Isolation And Dissociation Of Immune Complexes From Pleural Effusions Of Lymphoma Patients, Geeta V. Patel, Mangesh N. Satam, Gopal Nadkarni

Dr. Gopal Nadkarni

Immune complexes (IC) isolated from pleural effusions of lymphomas with favorable and unfavorable prognoses were of IgG type. These IC were further dissociated by ion exchange chromatography using 8 M urea. The antibody was found to be a high molecular weight protein (1.5 x l0 s daltons) and reacted with antihuman IgG immunologically while a second peak obtained on ion exchange chromatography may be an antigen moiety with a molecular weight of 3.2 × 10 4 daltons as it reacted immunologically with the antibody. Strong cytoplasmic fluorescence was observed with various cell suspensions of lymphomas when reacted with the antibody …

Accelerating Technology Commercializationuniversity Of Akron (Ohio) Using The Nsf I-Corps Model, Gopal Nadkarni, Elyse Ball, Daniel Hampu

Dr. Gopal Nadkarni

The paper explores the new technology commercialization model being followed at The University of Akron (UA).UA has implemented the National Science Foundation (NSF)Innovation ICorpsTMmodel since 2013. This paper describes how the NSF I-Corps model has changed the innovation culture at UA and allowed the academic faculty to explore the business potential of their intellectual property.Differences in implementation across several I-Corps Sites are explored. The lessons from UA's experience show that the I-Corps Sites program has been a resounding success and helped faculty and students to become more entrepreneurial in exploring the commercial value and demand drivers of technologies invented at …

Quantification Of The Effect Of Tool Geometric Features On Aspects Of Friction Stir Welding, Md. Reza-E-Rabby

Theses and Dissertations

In the friction stir welding (FSW) process, tool stirring and synchronized movement of the weld materials along a pre-existing seam line causes thermal gradients and severe plastic deformation resulting in the bonding of the adjacent materials. For a given set of welding parameters, tool pin geometries (dimensions, shape) and vertical/helical features that dictate the material motion also have significant effects on process response variables during FSW. Among the primary process controlling parameters in FSW, tool pin geometry and feature vary multifariously in terms of shape, dimensions, feature insertion technique depending on the weld material and application of joint. The current …

Design Of Experiments Analysis Of Non-Standard Inputs For The Optimization Of Friction Stir Welding, Ryan Widejko

Theses and Dissertations

The purpose of this study was to use non-standard Design of Experiments (DoE) inputs in Friction Stir Welding (FSW) to deduce relationships between various weld input and response variables. Typically, inputs for FSW DoE are tool rotational speed, welding speed and forge force. In this study, three different input factors were investigated: travel speed, thermal boundary conditions (TBC), and advance per revolution (APR). The experimental design included a full factorial with each factor at two levels plus two centerpoint runs. Response variables included weld temperature, microstructure, hardness, power, weld energy, and in plane forces.

An investigation of the effect of …