Consider the system shown in Figure P1.12.

a. First the damper is detached and the mass is excited by a force \(f(t)=20 \sin \omega t \mathrm{~N}\). Find and plot responses when \(\omega=0.8 \omega_{n}, \omega_{n}\), and \(1.5 \omega_{n}\). Assume that the initial conditions are zero. Compare your results from analysis to those from MATLAB ODE23 or ODE45.

b. Reattach the damper, and the mass is again excited by a force \(f(t)=\) \(20 \sin \omega t \mathrm{~N}\). Find and plot responses when \(\omega=0.8 \omega_{n}, \omega_{n}\), and \(1.5 \omega_{n}\). Assume that the initial conditions are zero. Compare your results from the analysis to those from MATLAB ODE23 or ODE45.

Also, show the phase lags of the responses in your plots.

Figure P1.12

Transcribed Image Text:

A (a) Massless and rigid bar m