Asee peer logo

Enhancing Learning Opportunities In A Combined Stress Laboratory

Download Paper |

Conference

2002 Annual Conference

Location

Montreal, Canada

Publication Date

June 16, 2002

Start Date

June 16, 2002

End Date

June 19, 2002

ISSN

2153-5965

Conference Session

Innovative Lab and Hands-on Projects

Page Count

12

Page Numbers

7.509.1 - 7.509.12

DOI

10.18260/1-2--10048

Permanent URL

https://peer.asee.org/10048

Download Count

299

Request a correction

Paper Authors

author page

William Szaroletta

Download Paper |

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

Main Menu Session 2168

Enhancing Combined Stress Laboratory Learning Opportunities

William K. Szaroletta Purdue University, West Lafayette, Indiana

Abstract: Combined stress theory coupled with laboratory practice has improved student comprehension in both a sophomore-level mechanics of materials and an upper-level experimental mechanics course. The Combined Stress lecture has traditionally developed the theory from free body diagram through beam deflection, with related homework problems providing analytical practice. Similarly, the Combined Stress laboratory has traditionally provided students an opportunity to experimentally and analytically verify and validate the combined stress theory. Good correlation between theoretical and experimental results was frequently obtained through the utilization of a carefully machined C-Clamp with strain gage instrumentation. However, the twist method of introducing axial and bending loads to the inside and outside surfaces of the beam portion of the C-Clamp instrumented strain gages limited both the accuracy and the amount of data that could be collected within a standard 110-minute laboratory session.

Recent Combined Stress laboratory upgrades have included introducing a load cell transducer, 3D modeling, Finite Element Analysis (FEA) and utilizing data acquisition (DAQ) hardware and software. The voltage output of the load cell can be directly correlated to the clamping force and provides a useful, new experimental baseline result. The FEA analysis outputs, at various load levels, provide a new analytical baseline result. Together, these new experimental and analytical baseline results have provided students significant new learning opportunities as they compare and contrast these results with their traditional analyses of the experimentally-obtained strain measurements. The DAQ has provided much improved granularity of test data in roughly the same timeframe with increased repeatability. Together, these upgrades have facilitated increased understanding of combined stress theory, introduced modern experimental methods in both lecture and laboratory, provided the students two new baselines against which to compare and contrast, given students a finer granularity data set upon which to base their analyses, and enhanced student experiences with technical report writing. This paper includes both an overview of the Combined Stress theory, analysis techniques, and traditional laboratory procedures and details of the success of the Combined Stress laboratory upgrade, operation, and outputs.

Introduction: Magill1 designed and implemented a combined bending and axial loading experimental mechanics laboratory using a C-Clamp that produced exceptional correlation between theoretical and empirical results. Improving on this laboratory was difficult as the lab was simple and had few drawbacks. Coyle2, et al presented an innovative derivative of Magill’s combined stress experiment utilizing a hacksaw instead of a C-Clamp. There are few drawbacks with Magill’s present C-Clamp laboratory. The upgrades of the combined stress laboratory to include data acquisition (DAQ), provide other analysis alternatives, introduce strain gage rosettes,and address some minor drawbacks were the primary motivations for the applied research presented in this paper.

Proceedings of the 2002 American Society for Engineering Education Annual Conference & Exposition Copyright Ó 2002, American Society for Engineering Education

Main Menu

Szaroletta, W. (2002, June), Enhancing Learning Opportunities In A Combined Stress Laboratory Paper presented at 2002 Annual Conference, Montreal, Canada. 10.18260/1-2--10048

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: © 2002 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