【Daily Question】Theoretical Foundation 2020.03.17
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Multiple-choice question: The axial force on the circular cross-section rod ABC is as shown in the figure. It is known that the diameter of rod BC is d=100 mm, and the diameter of rod AB is 2d. The maximum tensile stress in the rod is ( ). A.40MPa B.30MPa C.80MPa D.120MPa Answer: A Hint: Extra rewards will be given to those who can explain the solution process; the answer can be found in the response!
A: The axial forces in rods AB and BC are respectively FAB=300kN and FBC=100kN. According to the results obtained, the stress in each rod remains unchanged; therefore, the maximum tensile stress can be calculated to be 40 MPa.
The axial forces in members AB and BC are respectively FAB = 300 http://admintk.100xue*.com/UpLoadImage/2013-05-07/bd2d3c18-083f-4769-a301-14be195818c2.png kN, and FBC = 100 http://admintk.100xue*.com/UpLoadImage/2013-05-07/bd2d3c18-083f-4769-a301-14be195818c2.png kN. Based on http://admintk.100xue*.com/UpLoadImage/2013-05-07/9b7e8635-ec0e-42d8-a3d7-6532a6fd684a.png, we obtain: http://admintk.100xue*.com/UpLoadImage/2013-05-07/9aaec34f-f131-49fc-afc3-4bd4aafb3427.png and http://admintk.100xue*.com/UpLoadImage/2013-05-07/ccc948e4-23fd-4ed8-809a-4186ecc3dd88.png. The stress in each rod remains unchanged; therefore, the maximum tensile stress can be calculated to be 40 MPa.