Energy-Balance Method. - Continued

DOE-STD-3014-96

where:

effective missile mass;

coefficient of restitution

;

(6-8)

Vo =

velocity of missile before

impact.

For the entire aircraft impact (which is relatively deformable) on hard

structures, e is between 0 (plastic impact) and 1 (elastic impact). The

value of e is estimated based on the relative mass and stiffness of the

target and the missile. If the value of e cannot be easily estimated,

the lower and upper bounds of Ea can be calculated as in Paragraphs

e and f below.

e. Lower Bound Ea: A lower bound Ea can be obtained by assuming a

plastic impact (i.e., the aircraft moves along with the target after

impact), for which e equals zero and is less than m/Me. For such

cases,

m/Me

mVo

(6-9)

1 m/Me

Upper Bound Ea: An upper bound Ea can be obtained by assuming an

elastic impact (i.e., the aircraft and the target velocities after impact

are different), for which e=1. For such cases,