New Orleans, Louisiana
June 26, 2016
June 26, 2016
August 28, 2016
This evidence-based practice paper explores the use of a physical beam model and a matching spreadsheet that plots deflection, slope, shear, moment and loading diagrams as teaching tools. These tools were used to reinforce engineering theory as part of a second year civil engineering statics and solid mechanics course. The models consisted of three beams of known cross-section and stiffness, two supports which could be altered to provide clamped or simple support, and two dial gauges to measure beam deflection, all of which could be affixed to a base delineated with markings to quantify the distances between individual model components. Steel weights could be placed at any portion along the beam to apply vertical point loads to the beam. The physical model was accompanied by an electronic spreadsheet that calculated diagrams for slope, curvature, shear, moment and loading based on beam geometry, Young’s modulus and boundary conditions. In the first of two exercises, students examined beams with clamped, simple and free boundary conditions, observed linearity between loading and deflection, and used statics to calculate shear and moment diagrams. They also compared their calculations with beam diagrams produced by a matching spreadsheet. In the second session, after the students had been taught methods for calculating deflections in statically determinate beams, they examined model beams with various strategic boundary conditions and load patterns, looking for physical manifestations of deflection, slope and curvature (moment) within those beams. As part of this exercise, students chose a particular beam design and loading, and used a version of the spreadsheet that could plot all of the beam diagrams, including beam loading, based on the initial geometry, Young’s Modulus and boundary conditions of the beam and dial gauge-measured deflections under any loaded points. Seeing the spreadsheet back-calculate the loads they had applied from observed deflections did much to make students ponder the close relationship that exists between load, boundary conditions and deformed geometry. By comparing characteristics of the model beam with the spreadsheet diagrams, students were able to make and strengthen their connections between mathematical, visual and kinesthetic representations of beam bending. After each exercise, students were asked to provide written feedback on the effectiveness of the exercise through questions such “What are three specific things you learned about beams today?” “Which observations were unexpected or in conflict with your intuition?” “How did the physical model and spreadsheet enable you to better understand the operation of beams?” The students said the exercise helped them understand how various support conditions, material properties and applied loads effect the deflection of the beam. They also stated that the spreadsheet helped them understand the relationship between the deflection, slope and curvature. Changes to the beam supports sometimes produced deflection changes that conflicted with their intuitions, causing them to think more deeply about how beams actually work.
Pickel, D. J., & Brodland, G. W., & Al-Hammoud, R. (2016, June), Hands-On Beam Models and Matching Spreadsheets Enhance Perceptual Learning of Beam Bending Paper presented at 2016 ASEE Annual Conference & Exposition, New Orleans, Louisiana. 10.18260/p.25431
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