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Homework Help: Factor of Safety help

  1. Dec 20, 2017 #1
    1. The problem statement, all variables and given/known data
    Hello. I am trying to work out, the tensile stress, shear stress, and factor of safety.
    I have these to apply to it.
    Tensile strength = 460MPa
    Shear Stress = 280MPa
    Bolt Diameter of 8mm
    Force of 9kN
    Angle (a) = 50 degrees.

    2. Relevant equations


    3. The attempt at a solution
    Attempt at solution is attached below.
    Is what i done correct?
    And the correct answers?
  2. jcsd
  3. Dec 20, 2017 #2


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    Science Advisor
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    Gold Member

    Your conversion from mm^2 to m^2 is off by a multiple. And your calculation for bolt area is not correct. Otherwise, your force breakdown into shear and tension components looks good, and your FOS calcs should be ok once you make the above corrections. Note, however, that bolts subjected to shear and tension at the same time are weaker than individually applied shear and tensile loads of the same values, and you need to calculate the overall safety factor differently.. I don't believe the problem is asking you to do this, but it is not clear.
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