June 24, 2007
June 24, 2007
June 27, 2007
Division Experimentation & Lab-Oriented Studies
12.385.1 - 12.385.14
Comparison of the Strength to Weight Ratio of Variable Section Beams with Prismatic Beams
An experiment for examination of the stress distribution in a prismatic cantilever beam and a tapered cantilever beam of equal weight is proposed for national adoption. Strain gauges attached at four identical locations of the two beams will provide data regarding the state of stress for comparison purposes. Obtaining meaningful strain levels, and at the same time avoiding damage due to permanent set of the precious gauged specimens is always a challenge. To control this catch 22 situation, a backward analysis has been conducted to prescribe the allowable range of loads. The students must develop the mathematical model for predicting the levels of strain and stress in the two beams and manually calculate the expected levels of strain and stress. Modeling of the two different beams in ANSYS and comparison of the behavior of the beams may be added as an optional integral part of the project. This experiment vividly illustrates the advantages of the tapered beams over the prismatic ones. Students however, must comment on the extra manufacturing cost of the tapered beams in justification of their final design decisions in different applications.
I - Introduction
Laboratory experimentation is a critical final link for a thorough understanding and appreciation of scientific and engineering theories and principles. Every possible effort should be made not to deprive the future engineers or educators from this vital component of their education1. It is therefore necessary to continue development of effective and efficient pedagogical methods and techniques for the engineering laboratory experience2.
Laboratory apparatus is generally expensive due to low production levels, specialized features and significantly higher Design Costs built into the final cost. Such high costs may lead to the lack of vital laboratory apparatus and in turn deprive the engineering students from being sufficiently exposed to important concepts such as verification of the theory through experimentation, interpretation and analysis of data and gaining sufficient background for designing experiments. However, if blueprints of the designs of a (desired) apparatus are available, and on site machining capabilities exists, a major cut may be expected in the final cost. Such designs and blueprints may be generated in-house in collaboration with undergraduate engineering students3.
II - Objectives of the Experiment
The following major objectives were set at the inception of the project;
1. To develop an experiment for examination of the stress distribution in non-prismatic beams and comparison of their Strength to Weight Ratio with the prismatic beams, 2. To create an opportunity for collaborative research and design efforts between undergraduate engineering student(s) and faculty, Proceedings of the 2007 American Society for Engineering Education Annual Conference & Exposition Copyright © 2007, American Society for Engineering Education
Sepahpour, B., & Chang, S. R. (2007, June), Comparison Of The Strength To Weight Ratio Of Variable Section Beams With Prismatic Beams Paper presented at 2007 Annual Conference & Exposition, Honolulu, Hawaii. https://peer.asee.org/2707
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