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Comparison Of The Strength To Weight Ratio Of Variable Section Beams With Prismatic Beams

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2007 Annual Conference & Exposition


Honolulu, Hawaii

Publication Date

June 24, 2007

Start Date

June 24, 2007

End Date

June 27, 2007



Conference Session

Innovations in Mechanical Engineering Experiments and Labs

Tagged Division

Division Experimentation & Lab-Oriented Studies

Page Count


Page Numbers

12.385.1 - 12.385.14



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Paper Authors


Bijan Sepahpour The College of New Jersey

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Bijan Sepahpour is a Professor of Mechanical Engineering at TCNJ and currently serving as the chairman of the department of Mechanical Engineering and Engineering Science. He is actively involved in the generation of design-oriented exercises and development of laboratory apparatus and experiments in the areas of mechanics of materials and dynamics of machinery for undergraduate engineering programs. He served as the Program Chair of ASEE Division of Experimentation and Laboratory Oriented Studies (DELOS) in 2005-06 and is currently chairing that division. In the period of September 1997 to 2002, he served as the Primary and Technical advisor of TCNJ Lunar Rover teams. Professor Sepahpour is a registered professional Engineer and an active member of ASME and ASEE.

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Shou Rei Chang The College of New Jersey

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Shou-Rei Chang is an Assistant Professor of Mechanical Engineering at TCNJ.
Dr. Chang is an active member of Society of Automotive Engineers (SAE) and has served as the Primary and Technical advisor of the Mini-Baja teams at TCNJ for the past twelve years. For years, he served as the advisor for the department’s ASME club. His current scholarly interests include integrating research in classroom, machine design and computational mechanics, advanced stress analysis, finite elements and applications of numerical methods in engineering. Dr. Chang is an active member of ASME and ASEE.

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NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

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. 10.18260/1-2--2707

ASEE holds the copyright on this document. It may be read by the public free of charge. Authors may archive their work on personal websites or in institutional repositories with the following citation: © 2007 American Society for Engineering Education. Other scholars may excerpt or quote from these materials with the same citation. When excerpting or quoting from Conference Proceedings, authors should, in addition to noting the ASEE copyright, list all the original authors and their institutions and name the host city of the conference. - Last updated April 1, 2015