Matching Items (3)
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- All Subjects: Drag Coefficient
- Creators: Takahashi, Timothy
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
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