Question

(20%) Problem 3 An industrial machine has a mass of 430 kg and operates at a speed of 1500 rpm. It appears it has a rotating unbalance of moe-0.8 kg.m. A structural engineer suggested that the maximum transmitted force to the floor is 10000 N. The only isolation available are units, each of 7 x 106 N/m stiffness and a 0.1 damping ratio. a. What is the maximum allowable transmissibility of the force due to the rotating mass to the floor? b. What is the natural frequency associated with 'a' above? c. If a single isolator unit is used, what is the transmissibility? (5) (5) (5) d. How many isolator units are needed to reduce the force transmitted to the floor to the maximum allowable transmissibility? Which of the following two configurations in Figure 3 would you suggest? (5) B Figure 3 wW --C

Answer 1

Mass S008PM Speed mo to e tans mitted Max stittme dampi tio- 0 spes Calealtc the rot-Monal 4F 60 15 Yadls the max auoijabie transnis to Lafath the toor =0-8CIS 9119.2N

) 19719-2 Calculte the ntuul reseney 1X 106 430 127. 6 ad/s the freseney Yato 154 127.6 BSoeving from the E CY= 1an 1+C2$0) = ).

+2x0-1XY Co.50C42 04Y 4ac 29 2.12 t 2 2. 3- 063 89.7 Yad/s 157 1.35

89.7 Yad/s the tans missisuitg 9719.2 O507 dit Moye he discribrd maximum than ane SoLdo avaslcble Jas the syste the Ntu Can e deecasd soltoy mthe seies. Placng Seaty Sotor Pods n the at east 2 bclo Ma ximum aiowbke yanm