Measurement of roadway roughness and automobile ride acceleration spectra

See this work in the Center for Transportation Research Library catalog: https://library.ctr.utexas.edu/Presto/catalogid=31632The present study is designed to support an overall program for the evaluation and establishment of ride quality criteria in transportation systems. This report, which is restricted to the automobile, outlines the procedures and equipment employed to measure, record, and analyze automotive vibrations and highway or roadway roughness. Detailed automobile vibration responses and corresponding roadway roughness have been measured and recorded here for 20 different roadway sections which are typical of those found in the Austin - Travis County, Texas, area. Our highway roughness models are also compared to some of the roughness models found in the literature.Department of Transportation Office of University Research (Washington D.C.)Center for Transportation ResearchSee this work in the Center for Transportation Research Library catalog

Dynamic Modelling for Automobile Acceleration Response and Ride Quality Over Rough Roadways

See this work in the Center for Transportation Research Library catalog: https://library.ctr.utexas.edu/Presto/catalogid=5739Current interest in dynamics and vibration of ground transportation vehicles arises from the fact that excessive levels can lead to unsafe operation and give an uncomfortable ride to passengers. Current work by the U.S. Department of Transportation in high-speed tracked air-cushion and magnetically levitated vehicles centers around suspension design (both active and passive) for isolating guideway roughness effects from the main body of the vehicle. The work described herein arose from a need to evaluate vibration acceptance criteria for use in both vehicle systems design and guideway specification. This report deals with the first part of a study of automobile riding quality. Three different models of an intermediate sedan together with two different models for roadway roughness are compared. Roadway models compared are, first, a random input single track model with statistics governed by a power spectral density proportional to the square of the wavelength and, second, a model using a data sequence with a zero order hold where the data sequence is obtained from measured evaluation profiles of actual roadway sections. Frequency weighted rms acceleration responses are compared with serviceability indices of roadway test sections. It is concluded that the commonly used roadway model is inadequate and that more complete roadway information regarding statistics of right and left wheel tracks, together with a vehicle model including body roll motions, is necessary to predict ride quality. Use of the ISO Standard on Whole Body Vibration Tolerances as a basis of frequency weighting provides a good correlation with subjective response measured in terms of the roadway servicability index.Department of Transportation Office of University Research (Washington D.C.)Center for Transportation ResearchSee this work in the Center for Transportation Research Library catalog

General Hybrid Meshes and Its Application to Flow/Structure Interactions

I would like to express my profound gratitude to my advisor, Professor Yannis Kallinderis, for his advices, comments, and encouragement during my dissertation research. I am also grateful to him for asking questions that helped me consolidating my ideas and giving me considerable freedom to follow my own paths in research. His good sense of humor also has been invaluable to me while I was struggling with research. I would like to express my sincere appreciation to the members of my dissertation committee. I am extremely indebted to Professor Clinton Dawson, my co-advisor, for his comments and advices about my work as well as hosting me at the Institute of Computational Engineering and Sciences (ICES) and providing the excellent parallel computing resources of the Center for Subsurface Modeling (CSM) at ICES. My heartfelt gratitude must be expressed to Professor Graham Carey for his advices both in academics and life. Prof. Carey brought me a perspective view of my dissertation, and helped me to identify important parts and less important parts. I wish to thank Professor Spyridon Kinnas for giving me a chance to present m