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Homework Help: Engineering problems

  1. Feb 14, 2007 #1
    I'm trying to study for an exam, and there are a few problems that i cannot figure out:

    1) A rigid beam is supported at point B by a pin/hole connection and by two cables at points A and C, respectively.
    Initially (before load P is applied), there is no slack nor tension in either of the two cables. Under influence of load "P" both cables will be under tension and the beam will have rotated slightly in counter-clockwise direction. Neglect the weight of the beam in all of your calculations.
    Force P=500 [kN]
    Modulus of Elasticity E=200 [GPa] (same for both cables)
    Lengths on beam : a=1.6 [m] ; b=0.8 [m]
    Lengths of cables : L1 = 0.75 [m] ; L2 = 0.6 [m]
    Cross-section cables : A1 = 1100 [mm2] ; A2 = 1300 [mm2]

    Following Questions need to be answered:
    Force @ Point A
    Stress @ Point A
    change in length of L1
    Force @ Point C
    Stress @ Point C
    change in length of L2
    angle formed by beam and horizontal
    Support force B?

    2)Both, a brass tube and the steel rod located inside the brass tube are solidly attached to common end plates A and B at either end.
    The respective diameters are :

    Do = 5.2 [cm]
    Di = 3.0 [cm]
    d= 2.9[cm]
    alpha=19x10^-6/degree celcius
    alpha=12x10^-6/degree celcius
    Initially the assembly is stress free.
    Now the temperature increases simultaneously for the brass tube and steel rod by 60oC. As a result the distance L between the two end plates will change.
    Determine the resulting stresses in the brass tube and the steel rod, counting tension as positive and compression as negative.

    Following Questions to be answered:
    Stress in Brass in MPa
    Stress in Steel in MPa
  2. jcsd
  3. Feb 14, 2007 #2


    User Avatar

    Staff: Mentor

    Welcome to the PF. An important rule here is that you must show your work in order for us to help you. Also, the Homework Posting Template (that you apparently deleted instead of using) asks you to list the relevant equations and concepts that apply to your problems.

    Please do both so that we can provide some assistance.
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