
212 Forensic Engineering Fundamentals
criterion (HIC). e curve in Figure 7.14 has been approximately tted by the equation by
Versace (1971):
HIC =−
−
∫
()
()
()()
.
tt
tt
atdt
t
t
21
21
25
1
1
2
(7.44)
where a(t) is the acceleration at each increment of time in g units (32.2 /s
2
). e level of
concussion is when the HIC number equals or exceeds 700. Evaluating the integral
1
2
21
1
2
tt
atdt
a
t
t
−
∫
()()
(7.45)
where a is now the maximum value. We may express the ratio of two HIC numbers
given that
a
=
−
(7.46)
as represented in Equation 7.47:
HIC
HIC
11
=
∆
∆
v
v
.
(7.47)
Nahum et al. (1977) in their experiments on cadavers obtained pressure versus ...