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College of Engineering Quiz Department: Mechanical Engineering Subject: Dynamics of Machines (ME 243/221) Date : 24/04/2014 QN. 1. A shaft carrying 3 masses m1, m2, m3 at radii r1=1.135m< 113.40, r2= 0.822m<48.80, and 1.04m <251.40. The values of masses m1, m2, 1nd m3 are 1.2 Kg, 1.8 Kg, and 2.4 Kg respectively. Two masses are needed to dynamically balance the system using correction planes A and B. The distances of planes 1, 2, 3, and B from reference plane A are given below. A 1 2 3 B 0.854 1.701 2.396 3.097 Find out the mass radius product (mArA, and MBrB) and angular locations of correction masses to dynamically balance the system. QN. 2. Prove that the primary force and primary torque, and secondary forces and Torque for ‘ n’ in line cylinders are given by Fp= mB r w2 [coswt∑ πΆππ ∅π − ππππ€π‘ ∑ π ππ∅π ] MB reciprocating mass, Fp: primary Force Tp= mB r w2 [coswt∑ ππ πΆππ ∅π − ππππ€π‘ ∑ ππ π ππ∅π ] Tp primary Torque, an: distance of masses from 1st plane. Fs= = mB r w2 [cos2wt∑(πΆππ 2 ∅π − πππ2 ∅π ) − 2ππππ€π‘ ∑(π ππ∅π πΆππ ∅π ) ] Fs is Secondary force and TS is secondary Torque Ts = mB r w2 [cos2wt∑ ππ (πΆππ 2 ∅π − πππ2 ∅π ) − 2ππππ€π‘ ∑ ππ (π ππ∅π πΆππ ∅π ) ] QN3. The turning moment diagram of an engine represented below. Each mm2 area represents 3 N-m of energy. If resisting (mean) torque is uniform, determine the mass of the flywheel to keep the speed of flywheel 218-222rpm. The radius of gyration is 1.25 m. Suction stroke =400 mm2., Compression stroke= 1600 mm2, Expansion stroke = 8000mm2 and exhaust stroke= 500mm2. suction Compressio n π Exhaust 2π 3π Expansion 4π