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Unformatted text preview: Proceedings of the 2005 American Society for Engineering Education Annual Conference & Exposition Copyright 2005, American Society for Engineering Education Air Rocket Thrust Experiment Involving Computerized Data Acquisition, Calibration, and Uncertainty Analysis Michael R. Kessler Department of Mech. Eng., The University of Tulsa Abstract The development and modification of a laboratory experiment to determine the thrust characteristics of an air propelled rocket is described. The experiment is used in the junior level Instrumentations and Measurements course in the Department of Mechanical Engineering at the University of Tulsa. It involves elements of instrument calibration, computerized data acquisition, and uncertainty propagation. The experimental details of the laboratory are described along with the goals of the experiment and a description of the data analysis procedure. Student opinions of the lab experience as determined by a survey about the lab are presented and ways to improve the lab based on student comments are discussed. Introduction Three important concepts that are covered in most experimental methods courses are instrument calibration, computerized data acquisition, and propagation of uncertainty into a calculated result. While these concepts are often taught in the classroom, students benefit more by actively learning about these concepts in the laboratory. This paper describes an experiment that has been developed for the Instrumentation and Measurements course in the University of Tulsas Department of Mechanical Engineering. This junior level lecture-laboratory course contains bi- weekly laboratory exercises where student teams perform hands on experiments and then write up their lab experience and results in a formal technical lab report. The lively laboratory is particularly well received by the students because it involves the firing of an instrumented ballistic pendulum. The excitement of firing a ballistic air rocket in the laboratory adds to student motivation and helps to retain their attention. An initial version of the experiment was developed by Dr. Denis Zigrang at the University of Tulsa and subsequently modified . The modified experiment involves acquiring data using the computer and data acquisition software and calibrating several standard measurement transducers, e.g. accelerometer, rotary variable differential transformer (RVDT), and diaphragm pressure transducer. In the subsequent lab write up, the students are required to calculate the experimental uncertainty in the calculated impulse based on the elemental uncertainties in the measured signals. Experiment Description The purpose of the experiment is to determine the thrust characteristics of an air rocket. This experiment should familiarize students with typical instrument calibration procedures, computerized data acquisition, and the operation of a rotary variable differential transformer (RVDT), unbonded strain gage accelerometer, and pressure transducer. After completing the Proceedings of the 2005 American Society for Engineering Education Annual Conference & Exposition...
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- Spring '10