45 A pans assembly station on a production line exhibits a s

4.5. A pans assembly station on a production line exhibits a severe vibration problem. A simplified
schematic representation is shown in Fig. 4.26. Two large tables of mass m 1 and m2 are each mounted
to a sliding metal plate on resilient rubber mounts with shear stiffness K1 and K2, as shown. The
tables are each subjected to a vibrational excitation force, F1 (t) and F2 (t). The plates are able to
slide viscously on a second pair of defonnable rubber mounts, with shear stiffnesses K3 and K4. The
viscous sliding coefficients are 8 1 and 8 2 • The two plates are coupled by a shaft with longitudinal
stiffness Ks. Draw a linear graph for the system using the two forces F1 and F2 as inputs.

Solution

The loaded four wheel trailer shown in Figure P8.10 has a total mass of 5t and is pulled along a level road. Average resistance to motion (friction and windage) is 2 per cent of the total weight and acts at the same horizontal level as the applied force P. Determine the normal reaction at each of the front and rear wheels when the trailer moves:

a) at constant velocity

b) with forward acceleration 1.5m/s².

(Average resistance to motion is 2% of total weight is not required.)