Answer Happy

Problem #3(25 pts) A band brake depicted in Figure 2B-1 shows a drum with a mass moment of inertia of I = 2.26 kg.m’, and a band brake used to stop this drum from 2400 rpm in 1 sec. The band brake has the following dimensions: • Wrap angle º = 2100, • Drum radius r= 125 mm • Band width b= 100 mm • The lever arm length (a) = 300 mm • Center of drum (O) is aligned with lever pin. 1. Calculate the actuating force F necessary to stop the drum in the given time considering material properties given in table 16-4 in your textbook. 2. Check if the selected material will perform within the acceptable pressure. 3. If the brake is used to stop the drum 10 times every hour, calculate the minimum and maximum temperature of the brake assembly considering the following: • The mass of the drum is 4 kg • Drum is made from steel with specific heat of 450 J/(kg. °C). • The area exposed to surrounding 0.08 m² • surrounding temperature is 35 °C • forced ventilation is used at stream speed of 6 m/s • Hint : initially assume Tmax – Too = 100 °C then check if assumption was correct or not, perform max 2 iterations if required Figure 2B-1 (Drawing not to scale)