Identifier: strengthstiffnes00beck_0 (find matches)
Title: The strength and stiffness of steel under bi-axial loading
Year: 1915 (1910s)
Authors: Becker, Albert John
Subjects: Steel bars Axial loads Steel, Structural Theses
Publisher:
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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differencebetween the reading then taken and the zero reading. Twoother steel balls are embedded in the wooden strip on the I beam,one on each side of the ball under the plunger, at such a distancefrom, it that the tube always swings free on the center ball andone of the others. The center ball—the one under the plunger ofthe dial—was slightly higher than either of the others to insurea bearing on it at all times. By slipping the tube along^readingscould be taken rapidly. Zero readings were taken after atraverse of each axial line. A set of check readings was takenand where there was any appreciable variation, the average wasused. The dial was read to tenths of a division (ten thousandthsof an inch) and the check readings were never more than one one-thousandths of an inch at variance with the original set. As the later tubes were longer, the over hang of thebeam required to measure the thickness was so great that thevariation in the deflection due to the shift of the tube became
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57 noticeable. The apparatus vi/ae changed slightly and a 4J x2;- x 7/16inch T bar was clamped to a support at one end and the woodenbar carrying the dial was bolted to it. Readings were taken asbefore, but the zero readings were obtained by suspending thetube in two fine wire slings in such a manner that its weightcame on to the T bar in the same way as when it swung on the steelballs. Then with the plunger of the dial resting on the centralball—which in this case was set into a hole drilled in the stemof the T bar itself—the initial or zero reading was taken forevery position of the tube along an axial line. This gave slight-ly different zero readings for the various positions of the tube,but it removed any error arising by virtue of the deflection ofthe apparatus. Figure 16 shows the T bar device and the method ofsuspending the tube for zero readings. Measurements were taken every two inches along the axialgage lines and on lines half way between these. The latter lineshave bee

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