Question 2/3 [40/100] A motor system of mass M = 10 kg running at 2000 rpm was found to produce excess vibration due to rotating unbalance. The unbalance in the motor was estimated to be me = 0.1 kg.m. This is a 2-part question. You are to determine the design parameters for the isolator and absorber. Part (A) Consider the criterion F F max = 90 N where F- is the force transmitted to the ground. Use an isolator characterized as a spring of spring constant k; see Fig Part (A). Assume zero damping (c = 0.) x(t) isolator G k z c Part (A) be met? If not, max (A1) [5/40] What is the minimum reduction (%) to meet the criterion FT Fmax? (A2) [10/40] Assume an isolator of spring constant k = 20,000 N/m. Can F Fm use the table below and calculate the k value that can result in F = Fm max Part (B) Let the primary system be the motor and the isolator determined in (A2). To further reduce the force transmission, consider adding an absorber of mass m and k; see Fig Part (B). (B1) [10/40] Find m and k, with the constraint = m/m 0.3, such that the force transmission to the ground can be reduced to the minimum. (B2) [5/40] With m and k in (B1), what is the minimum force transmission to the ground. (B2) [10/40] Determine the natural frequencies of the absorber-motor system. Excitation frequency (rpm) 50,000 20,000 10,000 5,000 2.0 1.5 2,000 1.2 [1.1 1,000 0s 500 Amplification 200 100 0.0051 0.0127 0.0254 0.051 0.127 0.254 0.51 1.27 2.54 0.00254 Static Deflection A (cm) Percentage redution x(t) x(t), mo ko G k CM Part (B)