Matching Items (9)
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- All Subjects: Mechanical Engineering
- All Subjects: Drag
Description
Dimensional Metrology is the branch of science that determines length, angular, and geometric relationships within manufactured parts and compares them with required tolerances. The measurements can be made using either manual methods or sampled coordinate metrology (Coordinate measuring machines). Manual measurement methods have been in practice for a long time and are well accepted in the industry, but are slow for the present day manufacturing. On the other hand CMMs are relatively fast, but these methods are not well established yet. The major problem that needs to be addressed is the type of feature fitting algorithm used for evaluating tolerances. In a CMM the use of different feature fitting algorithms on a feature gives different values, and there is no standard that describes the type of feature fitting algorithm to be used for a specific tolerance. Our research is focused on identifying the feature fitting algorithm that is best used for each type of tolerance. Each algorithm is identified as the one to best represent the interpretation of geometric control as defined by the ASME Y14.5 standard and on the manual methods used for the measurement of a specific tolerance type. Using these algorithms normative procedures for CMMs are proposed for verifying tolerances. The proposed normative procedures are implemented as software. Then the procedures are verified by comparing the results from software with that of manual measurements.
To aid this research a library of feature fitting algorithms is developed in parallel. The library consists of least squares, Chebyshev and one sided fits applied on the features of line, plane, circle and cylinder. The proposed normative procedures are useful for evaluating tolerances in CMMs. The results evaluated will be in accordance to the standard. The ambiguity in choosing the algorithms is prevented. The software developed can be used in quality control for inspection purposes.
To aid this research a library of feature fitting algorithms is developed in parallel. The library consists of least squares, Chebyshev and one sided fits applied on the features of line, plane, circle and cylinder. The proposed normative procedures are useful for evaluating tolerances in CMMs. The results evaluated will be in accordance to the standard. The ambiguity in choosing the algorithms is prevented. The software developed can be used in quality control for inspection purposes.
ContributorsVemulapalli, Prabath (Author) / Shah, Jami J. (Thesis advisor) / Davidson, Joseph K. (Committee member) / Takahashi, Timothy (Committee member) / Arizona State University (Publisher)
Created2014
Description
A model has been developed to modify Euler-Bernoulli beam theory for wooden beams, using visible properties of wood knot-defects. Treating knots in a beam as a system of two ellipses that change the local bending stiffness has been shown to improve the fit of a theoretical beam displacement function to edge-line deflection data extracted from digital imagery of experimentally loaded beams. In addition, an Ellipse Logistic Model (ELM) has been proposed, using L1-regularized logistic regression, to predict the impact of a knot on the displacement of a beam. By classifying a knot as severely positive or negative, vs. mildly positive or negative, ELM can classify knots that lead to large changes to beam deflection, while not over-emphasizing knots that may not be a problem. Using ELM with a regression-fit Young's Modulus on three-point bending of Douglass Fir, it is possible estimate the effects a knot will have on the shape of the resulting displacement curve.
ContributorsSexton, Thurston Bryant (Author) / Takahashi, Timothy (Thesis director) / Jones, Donald (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2015-05
Description
This thesis focused on verifying previous literature and research that has been conducted on different spherical objects. Mainly, verifying literature that examines both how surface roughness contributes to the overall drag and how wake turbulence is affected by different surface roughness. The goal of this project is to be able to capture data that shows that the flow transition from laminar to turbulent occurs at lower Reynolds numbers for a rough spherical object rather than a perfectly smooth sphere. In order to achieve this goal, both force balance testing and hot-wire testing were conducted in the Aero-lab complex in USE170. The force balance was mounted and used in the larger wind tunnel while the hot-wire probe was mounted and used in the smaller wind tunnel. Both of the wind tunnels utilized LABVIEW software in order to collect and convert the qualitative values provided by the testing probes and equipment. The two main types of testing equipment that were used in this project were the force balance and the hot-wire probe. The overall results from the experiment were inconclusive based on the limitations of both the testing probes and the testing facility itself. Overall, the experiment yielded very limited results due to these limitations.
ContributorsMilroy, Maxwell (Author) / Takahashi, Timothy (Thesis director) / Adrian, Ronald (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The following analysis was conducted at the Arizona State University open loop wind tunnel. Two 1/24-th scale NASCAR models were placed in a wind tunnel test section and were adjusted to study drafting that commonly occurs at superspeedway racetracks. The purpose of the experiment was to determine how drafting affects a leading and trailing car through changes in distance. A wind tunnel model was developed consisting of two 2019 NASCAR Chevy Camaro race car models, two bar-style load cells, and a programmed Arduino UNO. Two trials were run at each drafting distance, 0, 0.5, 1, 1.5, and 2 car lengths apart. Each trial was run at a wind tunnel velocity of 78 mph (35 m/s) and force data was collected to represent the drag effects at each drafting location. Based on previously published experimentation, this analysis provided important data that related drafting effects in scale model race cars to full-scale vehicles. The experiment showed that scale model testing can be accurately completed when the wind tunnel Reynolds number is of the same magnitude as a full-scale NASCAR. However, the wind tunnel data collected was proven to be fully laminar flow and did not compare to the flow characteristics of typically turbulent flow seen in superspeedway races. Overall, the analytical drag analysis of drafting NASCAR models proved that wind tunnel testing is only accurate when many parameters are met and should only be used as a method of validation to full-scale testing.
ContributorsOlszak, Parker T (Author) / Takahashi, Timothy (Thesis director) / Kasbaoui, Mohamed (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
This thesis aims to design of wings for a laminate biped robot for providing locomotion stabilization during jump gliding. The wings are designed to collapse down during the jumping phase to maximize jump height and deployed back for gliding phase using anisotropic buckling in tape spring hinges. The project aims to develop a reliable dynamics model which can be utilized for design and evaluation of optimized systems for jump-gliding. The aerodynamic simulations are run on a vortex-lattice code which provides numeric simulations of the defined geometric bodies. The aerodynamic simulations assist in improving the design parameters such as planform, camber and twist to achieve the best possible Coefficient of Lift for maximizing glide distance. The aerodynamic simulation output is then plugged into a dynamics model built in Python, which is validated and correlated with experimental testing of a key wing designs. The experimental results are then utilized to improve the dynamics model and obtain better designs for improved performance. The simulation model informs the aerodynamic design of wings for sustaining glide for the biped platform and maximizing glide length to increase range.
ContributorsGadekar, Vipul (Author) / Takahashi, Timothy (Thesis advisor) / Aukes, Daniel (Thesis advisor) / Marvi, Hamidreza (Committee member) / Arizona State University (Publisher)
Created2020
Description
Automation has become a staple in high volume manufacturing, where the consistency and quality of a product carries as much importance as the quantity produced. The Aerospace Industry has a vested interest in expanding the application of automation beyond simply manufacturing. In this project, the process of systems engineering has been applied to the Conceptual Design Phase of product development; specifically, the Preliminary Structural Design of a Composite wing for an Unmanned Air Vehicle (UAV). Automated structural analysis can be used to develop a composite wing structure that can be directly rendered in Computer Aided Drafting (CAD) and validated using Finite Element Analysis (FEA). This concept provides the user with the ability to quickly iterate designs and demonstrates how different the “optimal light weight” composite structure must look for UAV systems of varied weight, range, and flight maneuverability.
ContributorsBlair, Martin Caceres (Author) / Takahashi, Timothy (Thesis advisor) / Murthy, Raghavendra (Committee member) / Perez, Ruben (Committee member) / Arizona State University (Publisher)
Created2021
Description
Multiphase flows are relevant to various industrial processes and are also a ubiquitous feature of nature. Atomization is a Gas-Liquid class of multiphase flow in which the liquid bulk disintegrates into a spectrum of drops. The final drop size distribution of fragmenting liquids is important and is crucial to quantifying the performance of atomizers. This thesis implements two models of ligament breakup. The first model provides a method to determine the droplet size distribution of fragmenting ligaments. The second model provides a relation between ligament stretching, aspect ratio and dimensionless properties like Ohnesorge and Weber numbers for ligaments being stretched by aerodynamic force. The first model by Villermaux et.al considers a ligament as a linear succession of liquid blobs which undergo continuous interplay during destabilization. The evolution of their size distribution ultimately rules the droplet size distribution which follow a gamma distribution [14]. The results show that the Direct Numerical Simulations (DNS) of ligaments with different perturbations fragmented into very few drops and cannot be used to confirm that they follow the predicted gamma distribution. The second model considers a ligament breakup due to Rayleigh-Plateau Instability and provides an equation for ligament stretching. Through test runs the proportionality constant in the equation is determined by a least square fit. The theoretical number of drops is compared with the number of drops resulting from the Direct Numerical Simulation of ligament with a sinusoidal perturbation. It is found that the wavelength of the initial perturbation does not determine the number of drops obtained by ligament breakup
ContributorsRama Krishna, Prathyush (Author) / Herrmann, Marcus (Thesis advisor) / Takahashi, Timothy (Committee member) / Huang, Huei-Ping (Committee member) / Arizona State University (Publisher)
Created2021
Description
This experiment investigated the effects of different vortex generator sizes and configurations on the induced drag of a 2006 Honda Accord, with comparisons to a control test. Tuft tests were carried out prior to any data collection. The tufts were placed along the roof and rear window of the vehicle for each of the five vortex generator types. Video was taken of the tufts for each set of vortex generators, allowing a visual comparison of the flow characteristics with comparison to the control. Out of the four vortex generators tested, the two that yielded the most substantial change in the flow characteristics were utilized. The data collection was conducted utilizing the two sets of vortex generators, one large and one small, placed in three different locations along the roof of the vehicle. Over a course of four trials of data collection, each vortex generator size and configuration was tested two times along a stretch of Interstate 60, with each data set consisting of five minutes heading east, followed by five minutes heading west. Several experimental parameters were collected using an OBD II Bluetooth Adaptor, which were logged using the software compatible with the adaptor. This data was parsed and analyzed in Microsoft Excel and MATLAB. Utilizing an Analysis of Variance (ANOVA) analytical scheme, the data was generalized to account for terrain changes, steady state speed fluctuations, and weather changes per night. Overall, upon analysis of the data, the vortex generators showed little-to-no benefit to either the fuel efficiency or engine load experienced by the vehicle during the duration of the experiment. This result, while unexpected, is substantial as it shows that the expenditure of purchasing these vortex generators for this make and model of vehicle, and potentially other similar vehicles, is unnecessary as it produces no meaningful benefit.
ContributorsMazza, Seth (Author) / Walther, Chase (Co-author) / Takahashi, Timothy (Thesis director) / Middleton, James (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05
Description
This experiment investigated the effects of different vortex generator sizes and configurations on the induced drag of a 2006 Honda Accord, with comparisons to a control test. Tuft tests were carried out prior to any data collection. The tufts were placed along the roof and rear window of the vehicle for each of the five vortex generator types. Video was taken of the tufts for each set of vortex generators, allowing a visual comparison of the flow characteristics with comparison to the control. Out of the four vortex generators tested, the two that yielded the most substantial change in the flow characteristics were utilized. The data collection was conducted utilizing the two sets of vortex generators, one large and one small, placed in three different locations along the roof of the vehicle. Over a course of four trials of data collection, each vortex generator size and configuration was tested two times along a stretch of Interstate 60, with each data set consisting of five minutes heading east, followed by five minutes heading west. Several experimental parameters were collected using an OBD II Bluetooth Adaptor, which were logged using the software compatible with the adaptor. This data was parsed and analyzed in Microsoft Excel and MATLAB. Utilizing an Analysis of Variance (ANOVA) analytical scheme, the data was generalized to account for terrain changes, steady state speed fluctuations, and weather changes per night. Overall, upon analysis of the data, the vortex generators showed little-to-no benefit to either the fuel efficiency or engine load experienced by the vehicle during the duration of the experiment. This result, while unexpected, is substantial as it shows that the expenditure of purchasing these vortex generators for this make and model of vehicle, and potentially other similar vehicles, is unnecessary as it produces no meaningful benefit.
ContributorsWalther, Chase (Author) / Mazza, Seth (Co-author) / Takahashi, Timothy (Thesis director) / Middleton, James (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05