Summative 3 -Target Analysis (2.2.5+2.2.2) Flashcards
Blast effects and FAE: Explosions
Definition:
recite at least one, of the four, definitions of an explosion
A nuclear, chemical or physical process leading to a sudden release of energy.
An explosion is the violent and rapid decomposition of energetic material to which will lead to violent pressure rupturing of any confining structure.
The violent expansion of gas at high pressure resulting in a shock wave and significant overpressure.
The explosion frees energy in the form of heat, light and a large volume of gas.
Blast effects and FAE: Explosions
List:
What are the three types of explosion?
Physical Explosion.
- natural - eg lighting strike, volcano
- structural - eg failure of a gas cylinder
Chemical Explosion.
Nuclear Explosion
Blast effects and FAE: Explosions
definition and list:
Define a chemical explosion.
List the four things that must be exhibited to qualify as a chemical explosion
The sudden expansion of gases into a volume much greater than the initial one, accompanied by noise and violent movement extremely rapid reaction of a chemical system to produce heat and gas.
Rapid expansion
Evolution of heat
Rapidity of reaction
Initiation of reaction
Blast effects and FAE: Explosions
Definition
Define a nuclear explosion
Sudden release of enormous quantities of heat by fission or fusion processes.
Blast effects and FAE: Explosions
Definition
Define the effects of an explosion, for both above and below ground
When ordnance functions, the explosive fill is rapidly changed into an expanding mass of hot gases accompanied by heat, light and noise.
Above Ground;
- Effect caused from blast and fragments.
Below Ground;
-Effect caused from ground shock, blast and ejecta.
Blast effects and FAE: Explosions
List
What are the three primary effects of an explosion?
Blast
Heat
Fragmentation
Blast effects and FAE: Blasts
Definition
Define a blast
Violent disruptive effect caused by an explosion. From the explosion there is an evolution of heat and gases and a shock front which emanates from the centre of the explosion.
Blast effects and FAE: Blasts
List
List the three main phases of a blast
Has a shock front
Followed by a positive pressure phase;
- High pressure gas behind the shock front.
Then followed by a negative pressure phase;
- A rarefaction following the positive phase.
Blast effects and FAE: Blasts
List / Definitions
List the four types of blast pressure and their definitions.
- Dynamic Pressure:
Results from the high wind velocity & increased density of the air behind the shock front.. - Incident Pressure:
Pressure exerted at right-angles to the direction of travel of the shock front. - Quasi-Static Pressure:
Results when an explosion occurs within a structure - overpressure eventually settles to a slow decaying level. - Reflected Pressure:
Instantaneous build up of pressure occurring when a shock front strikes a rigid surface in it’s line of travel.
Blast effects and FAE: Blast waves
List
What are the four behaviors exhibited by blast waves?
Reflection
Diffraction
Overpressure vs Distance
Overpressure vs Time
Blast effects and FAE: Blast waves
Definition
Define the blast wave behaviour: Reflection
The blast wave is thrown back at an angle to the original path.
The bouncing back of a wave after it strikes a boundary:
- Incident wave - the incoming wave.
- Reflected wave - the wave that is bounced back.
Blast effects and FAE: Blast waves
Definition
Define the blast wave behaviour: Diffraction
Breaking up or scattering of a wave by an obstacle.
Blast effects and FAE: Blast waves
Definition
Explain the concept of Mach Stem, in reference to blast wave behaviours.
Occurs when reflected blast wave coincides with the original wave.
Reflected wave is moving faster through the air already driven forward by the blast wave.
The two waves combine to increase the pressure.
Blast effects and FAE: Blast waves
Definition
Define the blast wave behaviour: Overpressure vs distance
The peak overpressures fall over distance:
– loss of energy due to heating of the atmosphere.
– Inverse-Square relationship of the wave pressure to distance due to
spreading.
Blast effects and FAE: Blast waves
Definition
Define the blast wave behaviour: Overpressure vs time
Behind the high pressure front the elasticity of the air causes the formation of a rarefaction or negative pressure phase.
This is somewhat longer duration than the positive phase.
Blast effects and FAE: FAE
List / Definition
List the three basic principles of a fuel air explosive (FAE)
Creating an aerosol cloud of fuel air mixture.
Which is then detonated to achieve an explosive effect
Not to be compared with the incendiary effect of napalm etc.
Blast effects and FAE: FAE
List
List the six types of fuel used in FAEs
Acetylene
Butane
Ethylene oxide
Kerosene
Propylene oxide
Aluminium
Blast effects and FAE: FAE
List
List the four steps that an FAE goes through, as the device functions
- Rapidly disseminated by an explosive bursting charge to form a cloud in the air.
- Fused to provide a delay after the initial burst during which the cloud expands to its optimum size.
- The fuze initiates or ignites which causes the cloud to burn to detonation.
- The blast wave forms inside the cloud and proceeds unabated to the edge of the cloud. The overpressure is therefor very high when the wave is an appreciable distance from the point of initiation.
Blast effects and FAE: FAE
List
List the 2 advantages of FAEs
List the 1 disadvantage of FAEs
ADV:
FAE provides larger overpressures at greater distances than HE would provide.
Requires little or no oxygen in the molecular structure therefore making a FAE explosion 3 to 5 times hotter than HE.
DIS:
FAE is dependent on weather conditions.
- Strong winds would prevent the development of the optimal shape from the initial burst.
Blast effects and FAE: FAE
List
List the three specific areas of testing regarding the improvement of FAE
Consistency in the size and mixture of the aerosol.
Means of delivery.
Precise control of detonation.
Blast effects and FAE: FAE
List
List the seven targets that FAE are effective against?
Structures. Concentrations of AFV and SP Guns. Parked aircraft. Minefield clearance. Ships. Bunkers / trenches. Concentrations of troops in the open.
Blast effects and FAE: FAE
FAE are a type of what effect?
this effect can also occur in sawmills, bakeries, silos etc.
Thermobaric
Target analysis:
Define
What is Overall Kill Probability?
The framework most frequently used by a weapon system designer on which to base an assessment of the effectiveness of his system is the concept of the overall kill chance.
Target analysis:
Definition.
Regarding the overall kill probability, show and explain the formula for the Probability Product Rule?
Probability of a kill (Pk)
– One round engagement.
Cumulative effect for multiple rounds.
PK = PH x PR x PL
Where:
P K = Probability of a Kill
P H = Probability of a Hit
P R = Reliability of the weapon system
P L = Lethality of the warhead or ammunition
Target analysis:
List / Definitions
List the three damage levels used in damage assessments, and define each one.
- Disablement
Disablement of the target to prevent it from doing it’s job is the damage level the ammunition designer aims to achieve. - Destruction
Destruction of a proportion of the targets engaged is an acceptable bonus. To design for destruction of the target leads to substantial overkill. - Neutralisation
The neutralising effect of fire stems from the apprehension induced in the target that the warhead propelled at it has a casualty causing potential.
It is therefore people, rather than material, which can be neutralised.
Target analysis: Damage levels
List
What design consideration should be considered when designing a weapon?
Weapons should be designed to attack the most important targets.
It is also necessary to design a piece of ammunition that will achieve a particular level of damage against a known target.
Target analysis: Types of targets
List
List the six types of targets frequently targeted by fire
People
Vehicles
Structures
Equipment
Aircraft
Complex
Target analysis: Types of targets
List
List factors influencing targeting of People
- Factors which affect their vulnerability are:
Attitude - presented area.
Protection equipment - body armour, occupation of buildings. - People are not simple targets but complex.
Target analysis: Types of targets
List
List factors influencing targeting of Vehicles
- The armoured vehicle is one of the principal targets.
- Main protection has to be defeated first with armoured vehicles:
ERA
Laminated armour
MBT - primary target
LAV, IFV, APC still require special consideration - Soft skinned vehicles are less of a problem:
Mobility
Less/no armour protection
Target analysis: Types of targets
List
List factors influencing targeting of structures
These range from the lightly constructed billet to the reinforced concrete bridge or strongpoint.
Because of the diversity of targets in this group, it is not economic to design a special warhead for each.
Target analysis: Types of targets
List
List types of equipment which can be targetted by ground forces
- Material found around the battlefield, principal types: Soft skinned vehicles. Aircraft on the ground. Storage dumps/maintenance areas. Electronic and communication equipment.
Target analysis: Types of targets
List
List the categories of Aircraft in flight targets
- Aircraft in Flight. This category of target is complex. The group presents particular problems of target acquisition and chance of kill. It is convenient to sub divide this target into:
Fast Moving Aircraft. This includes tactical strike aircraft, fast reconnaissance aircraft and certain drones and unmanned machines.
Slow Moving Aircraft. This includes transport aircraft and others, which operate at speeds of 200 300 knots.
Helicopters.
Target analysis: Types of targets
Definition
Define a complex target
Targets that have several different elements, generally people in combination with other types of target.
Target analysis: Target effects
Definition
Define Target effects
All targets need to be subjected to an attack IOT produce a physical effect, which is capable of causing casualties to people and disruption to and/or destruction of other targets.
Psychological and physiological effects can be achieved against people. However, this is difficult to quantify (except in the case of NBC attacks).
Target analysis: Methods of achieving target effects
List
regarding development and production, list the four qualities a weapon system must possess.
Simple.
Easy to make.
Easy to inspect.
Safe to transport, store and handle.
Target analysis: Methods of achieving target effects
Regarding development and production, what should be designed first:
the Warhead, or the means of delivery?
The warhead:
In practice, the weapon system design frequently precedes that of the warhead or a new warhead is required to boost the performance of an existing weapon.
In principle this approach is wrong.
Target analysis: Methods of achieving target effects
List
For conventional attack, what are the two practical ways of producing energy to a achieve an effect?
- Kinetic Energy (KE)
In the form of a solid missile (a “shot”) which dissipates its energy on impact and requires no triggering device to control the energy release. - Chemical Energy (CE)
In the form of a substance, which has considerable potential energy relative to its mass, which can be released when suitably initiated.
Such substances are known as high explosives and the initiation mechanism as a fuze.
Target analysis: target Groupings and key targets
List / Definition
List the three types of key targets that may present themselves to land forces
People
Attack of Armour
Aircraft in Flight
Target analysis: Target groupings
Reasoning
What are the two reasons we select specific key targets to counter rather than producing a large range of ammunition to counter anything found on the battlefield?
- It is unacceptable as well as impractical at the R & D phases,
- and the logistic implications make this approach uneconomic.
Attack on Aircraft: History
List
List 5 points on WW1 era anti air efforts.
Early biplanes: Slow and flimsy, easily damaged
Airships/Zeppelins: Slow, flammable gas bags
Machine guns
Searchlights
Modified artillery
Attack on Aircraft: History
List
List seven points on WW2 era anti aircraft efforts
Faster metal frame and skin aircraft
Dive bombers ~ Kamikaze
Multi engined bombers
Early jets
Dedicated AA guns
Radar
VT Fuzes
Attack on Aircraft: General principals
List
List the two general principals regarding the nature of the target.
Types of Aircraft targets
- fast moving
- slow moving
- helicopter
Vulnerability
Attack on Aircraft: Damage criteria
List
List the six damage criteria in the most commonly used criteria group
KK Kill The target suffers immediate and catastrophic disintegration.
K Kill The target is destroyed in less than 10 secs
A Kill The target is destroyed in less than 5 mins.
B Kill The target is defeated in less than 5 hours.
C Kill The target’s mission is not achieved (mission aborted)
E Kill The target may complete its mission but needs repair before it can fly again.
Attack on Aircraft: Aircraft vulnerability
List
List the 5 main areas of vulnerabilities on aircraft, including sub-areas
Structural Attack:
- Air frame.
- People, the aircrew.
Structural Attack:
- Fuel cells/tanks & lines.
- Engines.
Power transmission systems.
Flight controls.
Avionics.
Bomb load / Pay load.
Attack on Aircraft: Aircraft vulnerability
List
List 6 ways of reducing vulnerable areas
Armouring.
Burying sensitive components.
Concentrating sensitive components.
Duplicating components.
Separating components.
Self sealing fuel tanks.
Attack on Aircraft: Warheads
List
List the 7 common types of warheads
Blast:
- External
- Internal
Fragmentation (Inefficient 80% Wasted)
Fragmentation plus blast
Special kinetic energy:
- Discrete rod
- Continuous rod
Shaped charges
Sub projectiles
Cluster
Attack on Aircraft: Warheads
Reason
What factors can affect the effectiveness of a fragmenting warhead, explain the reason.
Fragment Mass - more fragmentation in smaller pieces is required to cover a larger area than conventional ground forces HE
Fragment Pattern - The designer is concerned with the shape of the frag beam width, and the density of the frag in the beam, as well as individual frag mass. The beam (frag spread) can be controlled to some extent by altering the shape of the warhead
Fragment Velocity - The designer strives for as high a velocity as possible. Most aircraft contain large amounts of aluminium - under a high energy impact this material burns and gives rise to a possible ignition source for fire plus pyrophoric effect.
Different configurations of frag, and the HE used to disperse it, can drastically change the way the frag spreads in the air at the point of detonation
Attack on Aircraft: Effects of altitude
List
What 4 factors affect warheads as altitude increases?
Density
Attenuation
Miss Distance
Altitude increases/warhead increases
Attack on Aircraft: effects of altitude
Definition
Explain miss distance,
why is modern development focused on miss distance rather than charge size
Miss distance is the distance that the warhead is designed to detonate from the aircraft.
Larger charge means larger, or more robust, delivery system, and the effects of altitude diminish the returns on larger warheads (10ft = 10lbs charge, 30ft = 270lbs charge)
Attack on Pers: Types of damage
List
List the two types of damage and their effects
Physical
- Casualties
- Damage to materiel
Mental
- affects will to fight
- Difficult to quantify on a well disciplined enemy
Attack on Pers: The target
List
The human is small and complex. What are the consideration of a human as a target?
- The human is small and complex: Measures around 0.42 m 2 Protected by CBA, helmet, eye protection, clothing. Standing, lying or moving. Fit, alert, tired, depressed. Bone, muscle, nerves, vulnerable areas. Injured by blast, frag or both.
- Target assessment difficult.
Attack on Pers: Modes of attack
List
What three things does the most efficient mode of attack require?
High probability of a hit.
Rapid transfer of energy.
No unnecessary overkill.
Attack on Pers: Modes of attack and frag
List
What are 3 common examples of energy transfer via frag?
What are three ways to produce frag?
Examples:
Grenades, mortars, projectiles
Ways of producing:
Generic HE, pre notched containers, pre formed frag
Attack on Pers: Control of Frag mass and velocity
List
list 4 ways that size of frag can be controlled
Case material and its mechanical properties.
Thickness of the wall.
Quantity of explosive and its position in relation to the fragmenting case.
Velocity of detonation of the explosive.