Question

conditions Ng = 0.1 m and to WALC 10 m/s. 3.30 A four-cylinder automobile engine is to be supported on three shock mounts, as indicated in Fig. 3.46. The engine-block assembly weighs 500 lb. If the unbalanced force generated by the engine is given by 200 sin 100 1 lb, design the three shock mounts (each of stiffness k and viscous-damping constant c) such that the amplitude of vibration is less than 0.1 in. Assume = 0.01

Answer 1

Given det? mass = 386.4 Weight = 500 lb Ansame 500 lb - see in & = 0.01 (given) f(1) = 200 sh wo at lb Solution: The equivalent stiffness of three parallel springs is na keq=kt kt le (keq = 3k The marimams amphitiche is (Less anume Aman = 0.05 cooly Fo Xma find lot are not [oront 0.05 - (3)0.01) Jasna 1 keq 200 0.05 67 (0.ol) J7-0. olja beq = 2.0001x0? Iblin Stiffness in each spring is 36 = keq = 2.0001805 eblin ks 2.0001 con = 6.667 x 16 h el min 3

= BC K = 6.667 X 6h eblin The equivalent damping ratio of thie parallel springs is. Car = ctetc Kes Damping ratio equivalent, Car ſkerm Ceq = & a beginn Ce -(0.01) (2x. 2.0001 x conta aj 3146 7.2114 Cep BCE 7-2114 - 7.2114 ca 3 C = 22,038 lb-slin