1. A 150-kg sewing machine operates at 1200 RPM and has a rotating unbalance of 0.45...

1. A 150-kg sewing machine operates at 1200 RPM and has a rotating unbalance of 0.45 kg-m. What is the max stiffness of an undamped isolator such that the force transmitted to the machine’s foundation is less than:

a) 1547

b) 2547

2. Redesign helicopter seat (i.e. find new stiffness) so that the maximum velocity experienced by the pilot is 1 mm/sec.

Expert Solution

Firs of all from given data we need to calculate Aplitude of unbalanced force.

Then find the speed ratio from the standard formula of vibration in terms of steady state apmlitude and spring constant.

By manipulating the expressions accordingly.

Then we can calculate the asked values easily.

See the complete solution below.

samet mamat answered 2 years ago

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