Northeast Atlanta Gaming

August 6, 2010

Armor and slope effects

Filed under: Armor — foodnearsnellville @ 12:26 am
Tags: , , , ,

One of the factors that made the T-34 a great tank in its day was thick and well sloped armor. I’ve always taken it for granted that this kind of technique was good for tanks, but the why of it was something I never seriously thought about. Until now. Knowing both armor thickness and slope is important in calculating defense factors.

The geometry is pretty straightforward. Line segment CD is perpendicular to the armor plate and is the thickness of the plate. The line segment CE is how much armor a projectile traveling in a straight line must penetrate. CE is related to CD by the cosine of the angle ECD, which by a variety of ways, can be shown to be the angle α.

Continuing will give you a listing of a program to calculate effective RHAs for any given slope.

#!/usr/bin/perl
use strict;
use warnings;

=head1 NAME

 slope.pl - calculates slope effects for given armor.

=head1 SYNOPSIS

 slope.pl [options] armor_thickness  slope_in_degrees
 Options:
       -help            brief help message
       -man             full documentation

=head1 AUTHOR

  author  : David Myers
  created : August 5, 2010
  modified: N/A

=head1 DESCRIPTION

 slope.pl - calculates slope effects for given armor.

=cut

use Getopt::Long;
use Pod::Usage;

my $help = 0;
my $man  = 0;

GetOptions('help|?' => \$help, man => \$man) or pod2usage(2);

pod2usage(-exitval => 0, -verbose => 1) if $help;
pod2usage(-exitval => 0, -verbose => 2) if $man;

my $armor = shift;
my $slope = shift;
$armor = 100 unless defined ( $armor );
$slope = "all" unless defined ( $slope );

my $pi = 3.14159265358;

my $header = "Armor   ----  Slope ----  Slope Factor ---- Effective RHA\n";
my $out_fmt = "%6.2f  ---- %6.1f ---- %5.2f ------------ %6.2f\n";

if ( $slope eq "all" ) {
    print $header;
    for ( my $s = 0; $s < 90; $s += 5 ) {
        my $slope_radians = 2.0 * $pi * $s / 360.0 ;
        my $factor = 1.0 / cos( $slope_radians );
        my $rha = $armor * $factor;
        printf $out_fmt, $armor, $s, $factor, $rha;
    }
}
else {
    my $slope_radians = 2.0 * $pi * $slope / 360.0 ;
    my $factor = 1.0 / cos( $slope_radians );
    print $header;
    my $rha = $armor * $factor;
    printf $out_fmt, $armor, $slope, $factor, $rha;
}
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