1. Military Explosives and Warheads

2. Explosion
Definition: A reaction that produces a change in the state of matter that results in a rapid and violent release of energy.
Military warhead: Inflict damage on a target through the rapid transfer of energy from the warhead to the target.
Types:
- Mechanical
- Chemical
- Nuclear
1. What is an explosion? Go over definition.
2. Three types of explosions:
a. Mechanical: (boiler explosion/steam) not applicable to warfare.
b. Chemical: Traditional weapons. Explosion achieved through a
chemical reaction.
c. Nuclear: Explosion achieved through a nuclear reaction.

3. Explosive
Definition: A material that can undergo a very rapid, self propagating decomposition, resulting in:
a. Formation of more stable materials
b. Liberation of heat
c. Development of a sudden pressure effect
1. Go over the definition of an explosive
a. Point out that explosives must produce the three listed items.

4. Explosive “Yield”
The amount of TNT to produce an equivalent blast (pressure) as that of the explosive itself.
Measured in pounds
Tomahawk
1000lb bullpup warhead
1000lb of TNT to produce the same explosion
Warhead’s weight: 215lb

5. Characteristics of Military Explosives
Availability & Cost
Sensitivity (impact, friction & heat)
Stability (chemical constitution, sun, temperature)
Power (or performance)
1. Availability and cost: Explosives must be produced from cheap raw materials available in great quantity. Manufacturing must be reasonably simple and cheap.
2. Sensitivity: Must be easy to ignite or detonate. But meet some concerns:
a. Impact - how much impact necessary to explode (for safety and example: don’t want armor piercing to explode on impact before penetration).
b. Friction - How much friction to cause snap, crackle, ignition and explode
c. Heat - How much heat will it take before it explodes.
3. Stability. Resistance to deterioration while stored (shelf life).
4. Power = Performance. Ability to work as intended.

6. Characteristics of Military Explosives (cont.)
Brisance
Density
Volatility
Hygroscopicity
Toxicity
5. Brisance. Shattering effect (fragmenting rounds). French for breakable.
6. Density. Weight of explosive per volume (how it is packed in casing)
7. Volatility. Readiness with which the substances vaporizes (undesirable). Vaporization can cause excessive pressure buildup inside of explosive casing.
8. Hygroscopicity. Measure of moisture absorbing capability (minimal amount desired). Moisture is bad because it absorbs heat.
9. Toxicity. Minimum is desired (can cause headaches or damage to body). We don’t want our operator hurt by gases or gas ejection system/vent dampers.
Lets talk about Chemical Explosives.

7. Chemical Explosive Reaction For a chemical to be an explosive, it must exhibit all of the following:
Formation of Gases.
Evolution of Heat.
Rapidity of Reaction.
“Uncontrollable Chain Reaction”
Initiation of Reaction.
1. Formation of Gases: burning a combustible forms a gas.
2. Heat: Heat accompanies all explosions. It is the rapid liberation of heat that causes the gases to expand and generate high pressures. This rapid generation of high pressure on the release of gases constitutes an explosion.
Although wood and coal produce more heat when burned , it is not rapid.
3. Rapidity of Action. Must be very rapid.
4. Initiation of Reaction; One must be able to initiate the above reaction.

8. Categories of Explosives
Low Explosives
Normally employed as propellants.
Burn rapidly (up to 400 m/s).
High Explosives
Detonate ( m/s).
Differentiated by Sensitivity:
Primary - Extremely sensitive to impact, friction & heat.
Secondary - Less sensitive. (May burn in small, unconfined quantities; otherwise will detonate.)
No sharp line of demarcation between low & high explosives.

9. Nuclear Explosives
Atoms of heavy unstable isotopes are split by high speed neutrons.
Split nucleus releases energy and more neutrons.
These neutrons go on to split more nuclei.
Reaction also produces heat and radiation.
Energy released is much greater than with chemical explosives (per weight of explosive).
Point out that with conventional weapons the heat produced adds little to the shock wave where in a nuclear blast the heat has a much larger affect.

10. Nuclear Explosions Fission Bomb -Atomic Fusion Bomb -Hydrogen
Grable – shot from atomic canon

11. Energy From a Nuclear Air Burst
Blast &
Shock
50%
Thermal
Radiation
(Heat) 35% 5%
10%
Residual Nuclear
Initial Nuclear Radiation
Go over graphic depicting the energy release from a typical air burst.
Show that heat is a major result from a nuclear blast.
Point out that nuclear weapons are used because they create a highly destructive shock wave and not because they produce radiation.

12. QUESTIONS?
Wednesday: Warheads

13. Functional Parts of Simple Warhead
Basic purpose of a warhead is to deliver destructive power to the intended target.
Basic warhead consists of:
Fuze
Explosive Fill
Warhead Case
All make up what is known as the “Explosive Train.”
When people think of explosive weapons, they think of the warhead.
The warhead is the primary element of the weapon. Remember the purpose of a weapons system is to deliver the warhead.
The basic warhead is more than just an explosive. There are three functional parts:
a. Fuse: includes the safety and arming systems.
b. Explosive fill - The main force of the warhead
c. Warhead casing - The casing is very important in most weapons>
- The casing can be the functional part with the explosive being
the driving force.
- The casing is the key to many special purpose weapons as you
see later.

14. High Explosive Train
The explosive train is a series of actions designed to make a stable material unstable through a given sequence.
Combination of High and Low explosives.
Initiating Force
Aux. Explosive
BANG!
{Pg 383, fig 13-2 – Old Book}
Several explosives are used in weapons and several different explosions must take place for the weapon to work.
a. In just the warhead there are normally several explosions that take place.
High Explosive Train explains the chain of events that happens in a warhead.
1. Detonator is a small charge that is MORE sensitive than the Booster or Main Charge.
2. Detonator is initiated electrically or by mechanical shock.
3. Detonator sets in motion a shock wave (detonation wave) that detonates the booster charge.
a. Although sensitive the detonator has little strength.
b. The detonator by itself can not set off the main charge.
4. The detonation of the booster charge results in a shock wave that is strong enough to initiate a high order detonation (main charge)
The detonation wave travels at high velocity.
Point out the main reason for the Explosive Train: SAFETY!!
To our personnel handling the ordinance
Storing it onboard
etc.
MAIN
CHARGE
DETONATOR
BOOSTER
MORE
less
Sensitivity

15. Warhead Energy Energy liberated in form of What are some by-products?
Thermal
Kinetic
Chemical
Nuclear
What are some by-products?
Pressure or shock wave

16. Warhead Characteristics
Damage Volume
Defines the destructive effectiveness of a given payload.
Attenuation
A function of distance from the origin of the blast, as the blast travels outward, the energy given off is dispersed over a greater area.
Propagation
Manner in which the energy spreads.
(i.e. - Isotropic & Non-isotropic)
{Pg 385, fig 13-3 – Old Book}
Isotropic- blast is uniform in all directions
Non-Isotropic- directed blast, not uniform in every direction

17. Blast Warheads
Designed to achieve target damage PRIMARILY from blast effects
Initial blast produces heat and overpressure.
Followed by a suction or underpressure.
Push/Pull causes the intended target to explode from the pressure differential.
1. After this initial pressure wave there is a decline in pressure (no new gas production to maintain the resulting pressure).
2. The pressure continues to decline and actually goes negative (like momentum of expanding gas).
3. The graph {pg 386, fig 13-4 – Old Book} shows how pressure changes with time after a blast.
- The graph shows what it is like at a given point.
- If you were further away from the center the magnitude of the pressure
change would be less but it would still be the same shape.
4. The initial pressure surge is called the positive phase and the vacuum which follows is the negative or suction phase.
5. Summary: It is the combined push -pull effect of the blast that causes a large target to explode due to the pressure internally.

18. Effect of blast wave
BLAST WAVE VIDEO
MORE BLAST WAVES

19. Blast Warheads Cont. Two types of blast waves:
Isotropic
Non-Isotropic
Mach Effect - A third wave resulting from the reflected wave overtaking the original shock wave.
Where the three waves combine is called the “Triple Point.”
Triple Point can increase a blast weapon’s effectiveness/radius range.
{Pg 387, Fig 13-5 – Old Book}
1. Blast propagation is normally in two forms:
a. Isotropic Explosion
- Uniform and Spherical in nature.
- Go out in all directions.
b. Non-isotropic
- Non uniform and directional in nature.
- These are the shaped charges and warheads such as armor piercing.
2. The mach effect is used to increase the effect of a blast.
3. Get the mach effect when detonate a warhead above the ground (air burst).
4. Mach effect is when the reflected (off the ground) shock wave catches up with the original (incident) shock wave. These waves add to make a new larger MACH WAVE.
- Remember from wave theory that waves are cumulative (added together).
5. The increased magnitude of the resulting sock wave has the affect of increasing the radius of effectiveness of the bomb .
6. By detonating a bomb a specific height above the ground, the radius of effectiveness can be increased up to 50% as compared to a bomb exploding on the ground.
7. The intersect of the incident, reflective and mach waves is called the triple point.

20. Blast Wave
MACH EFFECT

21. Creates a high pressure cavity of gas
Creates a high pressure cavity of gas. Water is forced outward rapidly by the gas expansion.
The bubble rarefies and increases in size.
When P w/in bubble < P of sea, expansion slows, then ceases, then compresses.
Each expansion creates a shock wave.
Similar to the air blast - creates an overpressure condition.
When the blast meets the surface, it’s reflected back down creating an even greater suction effect..
The gas expansion is very rapid and will overshoot equilibrium pressure with the water. (The bubble will now have lower pressure than the water outside the bubble).
External pressure then compresses the bubble until it returns to the same pressure and volume as at the first moment of the explosion. The gas is then compressed and the bubble pressure again increases and expands again.
This cycle is repeated until the energy is dissipated. Note the gas bubble will rise to the surface creating shock waves there.

22. Fragmentation Warheads
Blast energy is translated to the fragments of the weapons casing.
Approximately 30% of energy used to fragment the warhead.
Fragments propelled at very high velocities.
Exceeds the radius of a blast weapon.
Allows for greater inaccuracies in weapon use.
Examples of fragmentation weapons:
SM-2
Sidewinder
HARM
Grenade
Mortar
Harpoon – Blast Fragmentation

23. Fragmentation Warhead

24. Shaped Warhead (Charge)
Weapon impacts tgt, fuze at rear of weapon ignites apex of metal cone liner.
Cone collapses from apex forward.
Collapse results in the ejection of a high-velocity molten jet.
Pressure of jet>>>armor yield strength.
The jet is followed by a slug.
The jet liquefies some armor (spalling).
{Pg 396, fig – Old Book}
p. Fig in new book
1. The main charge is in a cone shape.
- The cone is set off from the rear.
- The charge explodes towards the center, creating a “jet” of high pressure
material.
2. The leading edge of the “jet” is traveling faster (approx meters/sec).
The trailing point travel slower causing the “jet” to spread out.
3. The jet point induces pressures of hundreds of kilobars at the surface of contact. The high pressures act as a fluid to get hydrodynamic penetration. This is the same effect as a cutting torch.
4. A slug follows the jet and goes through the hole cut..
Example:
MK-50 torpedo(?)
BLU – 97 A/B
TOW?

25. Shaped Charge

26. Continuous-Rod Warheads
Used to damage aircraft in the event of a near miss.
Series of rods connected and folded so that the series expands circularly.
Doesn’t produce as much destructive energy as the average fragmentation weapon.
{Pg 398, fig 13-13, 13-14, – Old Book}
1. Warhead has a metal rods that are joined together.
- The explosion cause the ring of connected rods to expand (a growing circle of metal)
2. Damage is caused by a cutting action.
3. Mainly used as an anti-air weapon. Don’t have to hit, just get close.
4. Being replaced with SAW (Selectively aimable warheads)
Examples are:
RAM – Rolling Airframe Missile (Will eventually replace the CIWS)

27. Continuous Rod

28. Special Purpose Weapons
Thermal Weapons
Used to start fires.
Napalm, etc.
Biological & Chemical Weapons
Used to kill with a minimal amount of destruction.
Biological – Microbes, Germs, Viruses
Chemical – Nerve, Blood, Blistering
Thermal: used in WWII and Vietnam.
Biological:
Anthrax, Ebola, etc.
Chemical:
Nerve: Sarin gas
Blood:
Blistering: Mustard gas
- Chemical agents were used in WWI, and are still maintained today by many countries (i.e. - Iraq during Desert Storm).
- Agent Orange?

29. Special Purpose Weapons
Nuclear
ThermoNuclear – Fission
Hydrogen - Fusion
Hiroshima – yield 125kT of TNT
Current Max Yield – 25MT of TNT (200 times!!)
Nuclear: Can talk about the Explosive Train and how it relates to Nuclear Weapons.
Thermonuclear – standard fission weapon
Hydrogen – trying to replicate the surface of the sun
Radiation – relies on radiation to kill personnel. Tends to leave equipment/buildings intact
EMP – High Altititude Airburst Nuclear weapon.
2. Pyrotechnics: illumination used in Vietnam. Also targeting for air strikes.
3. Anti-Personnel
- Warhead is full of about 800 darts that shoot out in all directions when
the warhead explodes.
- Normally in slight air burst.
- Range of about 200 meters
4. Cluster Bombs
- One of the capabilities of Tomahawk.
- Can fly down runway dropping bomblets. Produces lots of pot holes in the runway.

30. Special Purpose Weapons (cont.)
Pyrotechnic Warheads
Illumination (for lighting or signaling)
Smoke (white, yellow, red, green, violet)
Markers - WP (“Willy Pete” = white phosphorus)
Anti-Personnel Warheads
Designed kill or maim enemy troops or damage material
Projectile loaded with steel darts or wire.
Cluster Bomb Units (CBU)- Used for a variety targets over a wide pattern area.
Wide area of coverage = greater margin of error
Can contain specialized bomblets

31. Special Purpose Weapons (cont.)
Mines
Use underwater blast principles
Offensive and Defensive
Torpedoes - Homes on intended target
Mission / Mobility Kill - Hits ship’s screw
Hard Kill - explodes under ships hull
1. Mines
- Put on the bottom to wait for a target.
- We will discuss mine warfare in a future lesson.
2. Torpedo:
- Used to destroy ships or submarines. Can be sub, surface or air launched.
- Are underwater detonating warheads
3. Anti tank
- Armor piercing rounds (Kinetic Energy)
- Plastic goo (explosive) that doesn’t penetrate but causes spalling (chip or splintering) inside the tank.

32. Special Purpose Weapons (cont.)
Armor Piercing
Large diameter shaped charges.
KE defeat mechanism (“cookie cutter”).
Plastic defeat mechanism (massive spalling for lighter armor).

33. Questions?