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Calculating Stress experienced by fibre composite.

  1. Sep 17, 2010 #1

    I need to find the stress taken up by the fibres in the longitudinal direction, when a load of 25kN is applied to a continuous aligned composite with the diameter of 2cm. 60% matirx with E=2.8Gpa and 40% glass fibre E=73Gpa.

    Attempt at solution
    Known values

    V_m = 0.6, E_m = 2.8 Gpa ,
    V_f = 0.4 , E_f = 73 Gpa
    Cross sectional area A_C=πr^2= π〖(0.01)〗^2=3.142 ×〖10〗^(-4) 〖 m〗^2
    Longitudinal Loading F_c= 25 ×〖10〗^3 N

    i first found,
    F(fibre)/F(composite) = ((73×10^9×0.4)) / (73×10^9×0.4)+(2.8×10^9 )(0.6×3.142 ×10^(-4)) => F(fibre) = 24999.548 N

    Then using stress= F/A, Where A(fibre) = V(fibre)*(A(comp))
    therefore, stress on fibre is 198.91 Mpa

    Is that the right method and answer?
  2. jcsd
  3. Sep 18, 2010 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    One can check the answer against the average stress (load/area), and realize that assuming the two materials are of the same length, and that continuity applies, they must exhibit the same strain.
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