(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

a machine of mass 100 tonne generates a simple harmonic disturbing force when operating at a speed of 200rpm. to protect the floor and surrounding machinery it is proposed tp mount the machine on helical springs so that the transmissibility ratio is reduced to 0.1

Q1 determine the total stiffness of the springs required assuming the damping to be negligible ??

I'm having with this question because apparently certain sections you have to make "assumptions" which to me is more like guess work

2. Relevant equations

ωn = sqrt ( k/m)

tr = [itex]\sqrt{(1 + ( 2ζ ω/ωn) / ((1 - (ω/ωn)^2)^2 + (2ζ ω/ωn)^2) }[/itex]

3. The attempt at a solution

right what ive done is ive said that ζ=0 which gets rid of anything in the tr formula with ζ in as obviously anything multiplied by 0 is 0

so that leaves sqrt [ 1 / ((1-(ω/ωn)^2)^2) ]

i found ω is 200/60 x 2pi so you get something like ω=(20/3)pi

i then rearranged the tr formula two lines above to get ωn = 20

then used the formula ωn= sqrt (k/m)

rearranged to get k = ωn^2 x m and got a stupidly high answer so i imagine i done all the above wrong

can anyone give me any steps on what to do or where i'm going wrong, i have been tearing my hair out over it :(

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Vibration: find the stiffness of the spring

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