A 1000 kg turbine has a rotating unbalance of 0.1 kg.m. The turbine operates at a speed between 500 to 750 rpm. What is the maximum isolator stiffness of an undamped isolator that can be used to reduce th etransmitted force to 300 N at all its operating speeds

Respuesta :

Answer:

maximum isolator stiffness k =1764 kN-m

Explanation:

mean speed of rotation [tex]=\frac{N_1 +N_2}{2}[/tex]

[tex]Nm = \frac{500+750}{2} = 625 rpm[/tex]

[tex]w =\frac{2\pi Nm}{60}[/tex]

  =65.44 rad/sec

[tex]F_T = mw^2 e[/tex]

[tex]F_T = mew^2[/tex]

       = 0.1*(65.44)^2

F_T =428.36 N

Transmission ratio [tex]=\frac{300}{428.36} = 0.7[/tex]

also

transmission ratio [tex]= \frac{1}{[\frac{w}{w_n}]^{2} -1}[/tex]

[tex]0.7 =\frac{1}{[\frac{65.44}{w_n}]^2 -1}[/tex]

SOLVING FOR Wn

Wn = 42 rad/sec

[tex]Wn = \sqrt {\frac{k}{m}[/tex]

k = m*W^2_n

k = 1000*42^2 = 1764 kN-m

k =1764 kN-m