1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Pressure and strain

  1. Jan 22, 2017 #1
    1. The problem statement, all variables and given/known data
    A cylindrical vessel 2m internal diameter and 4m long has a wall thickness of 6mm. Strain gauges are installed on the vessel to measure hoop strain (see FIG 6).

    1)What is the maximum allowable pressure if a factor of safety of 4 is to be used?
    2 )What pressure would a strain of 40 με indicate?

    2. Relevant equations

    σ= pr/t for question 1
    and for question 2
    εο= σο - uσz/E
    σο = P X r /t and σz = P x r /2t

    εο =0.00004
    r = 1 m
    t = 0.006 M
    E = 290 GN
    3. The attempt at a solution
    for the 1 part i found it 0.75 Mpa

    for part 2 i work it

    εo = σo - σz /E

    P = (290000/ 1/0.006 - 0.3 x 1/2 x 0.006) x 0.00004 = 0.0008367398 Mpa

    is any of the above correct?if not i would like your advice,thank you in advance

    Attached Files:

    • pic.pdf
      File size:
      151.7 KB
  2. jcsd
  3. Jan 22, 2017 #2
    This looks like a duplicate of a previous thread. Is it, and, if so, why have you not just continued the previous thread? Also, there are algebra problems with your final equation.
  4. Jan 22, 2017 #3
    i didnt know i had to continue from the previous thread,i should go there then and post my questions?i cant understand the algebra problem,just put the numbers in the equation,is this not right?tha part 2 is the one that i had difficulties,didnt know how to solve without the poison ratio,...any advice?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted