An application demands that a sinusoidal pressure variation of 250 Hz be measured with no more than 2% dynamic error. In selecting a suitable pressure transducer from a vendor catalog, you note that a desirable line of transducers has a fixed natural frequency of 600 Hz but that you have a choice of transducer damping ratios of between 0.5 and 1.5 in increments of 0.05. Select a suitable transducer.

Answer :

Answer:

Explanation:

Given that:

f = 250 Hz

[tex]\delta[/tex]= 2%

[tex]f_n[/tex]= 600 Hz

[tex]\zeta[/tex] = 0.5 to 1.5  increment by 0.05

[tex]F = A sin (Xt)[/tex]

For 250 Hz = 250 cycle/sec

[tex]X = 2 \pi t 250[/tex]

[tex]X = 500 \pi t[/tex]

[tex]X = Asin (500 \pi t)[/tex]

[tex]\omega = 250 \\ \\ \omega_n = 600[/tex]

M = 0.98 , 1.02

[tex]M_{(w)}} = \sqrt{[1-(\frac{w}{w_n})^2 + ( 2\zeta \frac{w}{w_n})^2}[/tex]

[tex]\frac{1}{M} = [1-(\frac{w}{w_n})^2]+(2 \zeta \frac{w}{w_n})^2[/tex]

[tex]\zeta = \frac{w_n}{2w}\sqrt{\frac{1}{M^2}-(1-(\frac{w}{w_n})^2)^2}[/tex]

[tex]\zeta = \frac{600}{2(250)}\sqrt{\frac{1}{0.98^2}-(1-(\frac{250}{600})^2)^2}[/tex]

[tex]\zeta = 0.7183[/tex]

At 0.7183 value of damping ratio the error value was 2% at 0.98 value of M

[tex]\frac{1}{M} = [1-(\frac{w}{w_n})^2]+(2 \zeta \frac{w}{w_n})^2[/tex]

[tex]\zeta = \frac{w_n}{2w}\sqrt{\frac{1}{M^2}-(1-(\frac{w}{w_n})^2)^2}[/tex]

[tex]\zeta = \frac{600}{2(250)}\sqrt{\frac{1}{1.02^2}-(1-(\frac{250}{600})^2)^2}[/tex]

[tex]\zeta = 0.6330[/tex]

At  0.6330 value of damping ratio the error value was 2% at 1.02 value of M.

Hence, the damping ratio [tex]\zeta[/tex] of the transducer must be placed between 0.6330 to 0.7183

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