1161 
-7- 
pct’ 
aes 2 e ™ sin fi Boos 
2 _ ect" 
é = Po 1-omsin@, om sin® . msin — ent’ 
mn sin@ [—2o _ _ pc pc 
m sin? 
Writing 
ehjasBCu = (22) 
mn sin@ 
these may be expressed in the simpler forms 
2. ae CGE Ser CaaS (23) 
Po 
E+: seas gt | Phe Guest eet! _ ie eont’ } (24) 
mn“ (€ — 1) € a 
g = te (em emt!) (25) 
mn = 
The maximum veloctty occurs when p= 0, i.e. when 
oS 1 
nt = vey, 1095 Ga (26) 
and its value is 
€ 
- 2p rf 
iG (7) 
Smax mn 
€ 
log, € Sat 
c e an * €- 
Some values of SST Ore given in column 3 and of € in column 4 in Table I. 
e-1 
These curves can be used to find the maximum velocities with which a plate is projected at right angles 
to its plane by the pressure wave from a submarine explosion. A few examples of the use of these 
curves are shown in Table II. 300 1b. of T.N.T. gives a pressure wave which falls to half value in 
0.3 milliseconds so that n= 2.3 x 10? sect, For plates of thickness t = I inch, 1 inch, 3 inches 
and 6 inches, the values of pc/nm are 12.1, 3.0, 1.0 and 0.5, These are the values of € for these 
plates during normal incidence. Values of logy9 € are given in column 2 and the values of 
€ € 
10919 ee =f taken from Figure 7 in column 3. Values of € © ~ 1 are given in column 4. 
(5 
og, € ST 
Values of a4 Jona laio| = are shown as functions of logy, € in Figure 7. 
At 50 feet from the explosion Preset ton/square inch, so that 
2p = 2x i.5ux 10° _ 1.34 x 10° 
—— bagi 
mn mx 2.3 x 10 m 
5 diy = I F : nese ; 
Values of Con, = mm & are given in column 5 for normal incidence and in colume 9 for 
incidence @ = 10°, It will be secn that as the angle of incidence decreases the velocity with which 
the plate is thrown in the direction perpendicular to its surface decreases. This decrease, however, 
diminishes as the thickness of the plate increases. For extremely thick plates the steel would act 
as a perfect reflector and the pressure at its surface would be double that tn the incident pulse, so 
that é would be independent of the angle of incidence. Values of t and é for normal incidence 
of plate at 50 feet from 300 1b, T.N.T. sre also given in columns 6 and 7 of Tale |. 
Maximum sesee 
