In a drop-weight impact test, a 1 in. diameter spherical ball weighing 0.15 lb is dropped freely on 0.120 in. thick [0=±45=90]3S carbon fiber–epoxy beam specimens and the rebound heights are recorded....

In a drop-weight impact test, a 1 in. diameter spherical ball weighing 0.15 lb is dropped freely on 0.120 in. thick [0=±45=90]3S carbon fiber–epoxy beam specimens and the rebound heights are recorded. The beam specimens are simply supported, 0.5 in. wide and 6 in. long between the supports. The drop heights, rebound heights, and specimen deflections in three experiments are as follows:

(a) Calculate the energy lost by the ball in each case.

(b) Assuming that all of the energy lost by the ball is transformed into strain energy in the beam, calculate the maximum deflection of the specimen in each case. The flexural modulus of the laminate is 20 3 106 psi.

(c) Explain why the measured maximum deflections are less than those calculated in (b).