EGR 283 Quiz #5 Solutions


All results must be given to the precision used in the textbook.  Assume that the data are known to the same precision.  Thus, when a value of 2 kips is given, it is assumed that it is known to 3 digits; i.e., 2.00 kips.  You may receive partial credit if you show your work (on the reverse).  The units requested must be given with all answers. Print this page and write the answers in the blanks.  Sign the statement at the bottom.  Then submit the page before class on Monday.

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1. The compressive strain on the upper surface of a beam of square cross section (140 mm x 140 mm) is 1.37 x 10-3.  There are no plastic regions.  Find the radius of curvature.  Give your answer in meters. 51.1 m
2.The section modulus for a structural steel beam is 0.695 in3.  If the allowable stress is 12 ksi, what bending moment in kip-in is permitted? 8.34 kip-in
3. The average stress in a steel bar is 50 MPa due to pure bending.  What is the stress (in MPa) in the region near grooves in the bar if the stress concentration factor is 2.4? 120 MPa
4. For Example 4.06 on page 251 replace the yield stress of 240 MPa by 190 MPa.  Use the method explained in class and Fig. 4.45a (with 190 MPa in place of 240 MPa) to determine the bending moment.  Give your answer in kN-m. 29.1 kN-m
5. True or False?  For a beam which has become partially plastic, upon removal of the load, the recovery is entirely elastic. (circle one) True
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