SA03 - Blast Effects and Target Analysis Flashcards
1
Q
Blast Effects
Definition of Explosion
A
An explosion is the violent and rapid decomposition of energetic material to which will lead to violent pressure rupturing of any confining structure.
2
Q
Blast Effects
Types of explosion
A
- Physical (Mechanical)
- Chemical
- Nuclear
3
Q
Blast Effects
Primary effects of explosion
A
- Blast
- Heat
- Fragmentation
4
Q
Blast Effect
3 Phases of blast
A
- Shock front
- Positive
- Negative
5
Q
Blast Effect
Types of blast pressures
A
- Dynamic
- Incident
- Quasi-static
- Reflected
6
Q
Target Analysis - REMEBER THIS QUESTION
What is rarefaction?
A
Area of low pressure immediately following the positive phase
7
Q
Blast Efffects and FAE
Principle of FAE
A
Creates an aerosol cloud of fuel air mixture which then detonates to achieve an explosive effect.
8
Q
Blast Efffects and FAE
Types of fuel used in FAE
A
- Acetylene
- Butane
- Ethylene oxide
- Kerosene
- Propylene oxide
- Aluminium
9
Q
Blast Efffects and FAE
Advantages of FAE
A
- Provides larger overpressure at a greater distance than HE
- Requires little to no oxygen in the molecular structure making the explosion 3 to 5 times hotter than HE
10
Q
Blast Efffects and FAE
Disadvantages of FAE
A
- Dependent on weather conditions
11
Q
Blast Efffects and FAE
Types of targets for FAE
A
- Structures
- Concentrations of AFV and SP Guns
- Parked aircraft
- Minefield clearance
- Ships
- Bunkers / trenches
- Concentrations of troops in the open
12
Q
Blast Efffects and FAE
Define Blast
A
A violent disruptive effect that produces heat, gases and a shock front which emanates from the centre of the explosion.
13
Q
Formula for Probability Product Rule
A
P(K) = P (H) x P (R) x P (L)
K = Probability of a Kill
H = Probability of a Hit
R = Reliability of the weapon system
L = Lethality of the ammunition
14
Q
Target Analysis - REMEMBER THIS QUESTION
What are 3 levels of damage which ammunition designer may want to achieve?
A
- Disablement
- Destruction
- Neutralisation
15
Q
Target Analysis
Types of target engaged in battlefield
A
- People
- Vehicles
- Structures
- Equipment
- Aircraft
- Complex
16
Q
Target Analysis
Types of Armoured vehicles
A
- Main Battle Tanks (MBT)
- Light Armoured Vehicles (LAV)
17
Q
Target Analysis
Types of aicrafts
A
- Fast Moving Aircraft
- Slow moving aircraft
- Helicopters
18
Q
Target Analysis
Requirements for design of Weapon systems
A
Weapon systems must be:
- Simple
- Easy to make
- Easy to inspect
- Safe to transport, store and handle
19
Q
Target Analysis - REMEMBER THIS QUESTION
2 types of energy used in ammo design
A
- Kinetic Energy (KE)
- Chemical Energy (CE)
20
Q
Target Analysis
What types of Defensive Aid Suites (DAS) are on battle tank?
A
- Sensor package - Active and Passive
- Counter measures
- Electro Optic Attack
- RF Attack
- Decoys
21
Q
Target Analysis - REMEMBER THIS QUESTION
Describe Kinetic Energy
A
Energy in the form of a solid missile, which dissipates its energy on impact & requires no triggering device to control the energy release.
22
Q
Target Analysis - REMEMBER THIS QUESTION
Describe Chemical Energy
A
In the form of a substance, with a considerable potential energy, relative to its mass, which can liberate that energy when suitably initiated. Such materials are familiar as HE and the initiation mechanism as the fuze.
23
Q
Attack on Personnel
Types of damage on personnel
A
- Physical
- Mental
24
Q
Attack on Personnel
Designer criteria for most efficient mode of attacks
A
- High probability of a hit.
- Rapid transfer of energy.
- No unnecessary overkill.
25
# Attack on Personnel
What are the major fragment producers?
* Generic HE projectiles.
* Pre notched containers.
* Pre formed fragments.
26
# Attack on Personnel - REMEMBER THIS QUESTION
How the control of fragment size is acheived?
* 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
27
# Attack on Personnel - REMEMBER THIS QUESTION
How the fragment velocity is controlled
* Amount of explosive behind the fragment wall
* Charge density and velocity of detonation
* Density of the wall material
28
# Attack on Personnel
Factors affecting fragment performance of an attack on personnel
* Distribution of Fragmentation
* Orientation of the projectile to target
* Height of burst (2-4 m optimum)
* Average area of exposed target
29
# Attack on Personnel - REMEMBER THIS QUESTION
Factors affecting energy transfer of fragments.
* Fragment mass and velocity
* Fragment cross sectional area
* Stability of the fragment
30
# Attack on Personnel
Categories of wound
- Mild
- Severe
31
# Attack on Personnel - REMEMBER THIS QUESTION
How does orientation of projectile affect distribution of fragments?
* The most effective distribution will be achieved when the axis of the projectile is vertical.
* As axis moves away from the vertical, an increasing amount of fragmentation is projected harmlessly into the air or lost in the ground.
32
# Attack on aircaft - REMEMBER THIS QUESTION
What is the aircraft damage criteria for defence?
* Defence industry
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 abort).
E-Kill The target may complete its mission but needs repair before it can fly again.
* Criteria for completeness
**Ft - Flight Kill**. The target aircraft will become permanently incapable of maintaining directed flight within time "t" of sustaining the damaging hit. Destruction of the aircraft is implied, and the aircraft fails to complete its mission, eg F5 seconds.
**Ct - Continuance Kill**. The target aircraft is unable to continue with its stated mission within the time "t" of sustaining the damaging hit. The mission is frustrated; the aircraft may be destroyed.
**Et - Effectiveness Kill**. The aircraft receives damage of a degree sufficient to cause it to be grounded for repairs for time "t" before it can undertake further missions.
33
# Attack on aircaft - REMEMBER THIS QUESTION
What are the Vulnerable areas of an aircraft?
* Air frame.
* People, the aircrew.
* Fuel tanks & lines.
* Engines.
* Power transmission systems.
* Flight controls.
* Avionics.
* Bomb load / Pay load.
34
# Attack on aircaft - REMEMBER THIS QUESTION
Types of warheads to attack an aircraft
* Blast:
External
Internal
* Fragmentation (Inefficient - 80% Wasted)
* Fragmentation plus blast
* Special kinetic energy:
Discrete rod
Continuous rod
* Shaped charges
* Sub-projectiles
* Cluster
35
# Attack on aircaft - REMEMBER THIS QUESTION
What percentage of fragmentation are wasted in a fragmentation warhead?
80%
36
# Attack on aircaft
What is Preferential Fragmentation?
HE+Frag in one narrow beam/band in one chosen direction
37
# Attack on aircaft - REMEMBER THIS QUESTION
Effects of altitude on blast forehead
To be effective, a blast wave requires a medium through which it can travel. As the medium becomes less dense, the effects of blast warhead decrease.
38
# Remember this question
How the EO designers can make the fragmentation efficient?
* Fragment Mass
* Fragment Pattern
* Fragment Velocity
39
# Attack on Armour
When did the first tanks appear?
16 Sep 1916
40
# Attack on Armour
Early methods of attacking tanks
* Large calibre rifles with hardened projectiles
* Concentrated Machine gun fire
* 6 grenades tied together
* Early blast mines
* Flame throwers
41
# Attack on Armour - REMEMBER THIS QUESTION
Types of Armour
* Rolled Homogeneous Armour (RHA)
* Spaced Homogenous
* Ply
* Face hardened
* Reactive – Explosive Reactive Armour (ERA)
* Composite (Chobham)
* Slat (Bar)
42
# Attack on Armour
What are the 3 Tank damage assessment criteria
- M - Mobility Kill
- F - Firepower kill
- K - Completely destroyed
43
# Attack on Armour
APC and MICV damage assessment criteria
F – Firepower kill
P – Payload kill
44
# Attack on Armour - Remember this question
Types of high energy attacks
- Kinetic energy (KE)
- Chemical Energy (CE)
- Combination of both
45
# Attack on armour - REMEMBER THIS QUESTION
Types of Shot Failure
- Barrelling
- Shattering
- Lateral Bending
46
# Attack on Armour - REMEMBER THIS QUESTION
Ways to increase penetration of armour
- Lengthening of barrel
- Rocket assistance
- Improve steadiness of the shot
- Lengthen the projectile
- Use of segmented long rod penetrators
47
# Attack on armour - REMEMBER THIS QUESTION
Factors affecting shape charges
* Cone Diameter
* Shape of Liner
* Liner Material (Copper, Steel, Aluminium)
* Stand – Off Distance
* Rate of Spin
48
# Attack on armour - REMEMBER THIS QUESTION
What are Behind Armour Effects (BAE)?
Ones that contribute directly or indirectly to the lethality of a particular mode of attack
49
# Attack on armour - REMEMBER THIS QUESTION
BAE types
* Luminescence
* Spalling
* Heat / Fires
* Overpressure
50
# Attack on armour
Delivery methods of KE and CE
* Guns
* Grenades
* Mines
* Aircraft bombs
* Missiles
51
# Kinetic Energy attack on Armour
What is Kinetic Energy attack?
Hitting the target armour with a projectile of sufficiently high velocity to achieve penetration
52
# Kinetic Energy attack on Armour - REMEMBER THIS QUESTION
Types of stabilisation
* Spin -7:1length:diameter ratio for spin
* Fin- 15:1 length:diameter ratio for fin
53
# Attack on armour - REMEMBER THIS QUESTION
What is barrelling?
Due to shot material being to soft, this leads to direct compression failure in the shot material at the mid point. This increases the sectional area of the shot preventing penetration.
54
# Attack on armour - REMEMBER THIS QUESTION
What is shattering?
* Raising the hardness of a steel shot, whilst increasing its compressive strength, makes the shot brittle. On impact severe tensile hoop stresses are set up in the nose of the shot (small cross sectional area).
* At high striking velocities, which raise the loading on the shot, the shot nose can fail under these stresses and longitudnal cracks are formed along the length of the shot.
* The shot is said to "break up", where the effect is more catastrophic and the shot disintegrates, this is known as shatter.
55
# Attack on armour - REMEMBER THIS QUESTION
What is lateral bending?
At high angles of attack the shot is subjected to severe lateral stresses, both shear and bending, particularly towards its rear end.
56
# Kinetic Energy attack on Armour
What is the purpose of a ballistic cap?
* Initial indentation.
* Prevent shot failure (particularly steel projectiles).
* Rotate shot to normal.
57
# Kinetic Energy attack on Armour
What are the 2 types of discarding sabot?
- Pot
- Petal
58
# Kinetic Energy attack on Armour
Full name of
a) APFSDS-T
b) APDS-T
c) APCNR
A. Armour Piercing Fin Stabilised Discarding Sabot - Trace
B. Armour Piercing Discarding Sabot - Trace
C. Armour Piercing Composite Non Rigid
59
# Shape charge attack
What is the definition of shape charge?
A charge shaped so as to concentrate its explosive force in a particular direction.
60
# Shape Charge Attack - REMEMBER THIS QUESTION
Diagram of parts of a shape charge
Slide 10 of the Shape charge attack powerpoint
* Ballistic cover
* Empty space and shape assist
* Conical liner
* Base Detonator
* Explosive
* PIBD Fuse
61
# Shape Charge Attack
What cone diameter is recommended when engaging MBT (tank)?
85mm
62
# Shape Charge Attack - REMEMBER THIS QUESTION
What stand off distance gives peak performance?
5 Cone diameters
63
How do shaped charges achieve their effect?
By having an intense concentration of kinetic energy.
64
With a shaped charge the residual energy lies within what?
* Unconsumed part of the jet.
* Fragments of metal.
65
# HESH, HEP-T
Diagram of general principle of HESH
Slide 7 of HESH powerpoint
66
# HESH, HEP-T - REMEMBER THIS QUESTION
What is the scab size from an HESH attack?
Depends on the weapon and thickness but usually 1 1/4 or 1 1/2 its own diameter
67
# HESH, HEP-T
Design characteristics of HESH
* Head must be collapsible
* Head must not be pointed
* HE must have a high V of D
* Explosive be plastic in nature
* Fuze must be in the base
* Inert bituminous pad in nose
68
# HESH, HEP-T - REMEMBER THIS QUESTION
What is reverse impact detonation (RID)?
Detonation occurs before the fuze can produce detonation of the filling, the shock wave will be travelling in the wrong direction
69
# HESH, HEP-T - REMEMBER THIS QUESTION
Different ways to defeat HESH?
- Spaced armour
- Skirting plates
- Grooved
- Reactive armour
70
# HESH, HEP-T
WHat are the other targets HESH can be used against?
- Emplacements
- Pill-boxes
- Concrete structures
71
# HESH, HEP-T
Factors affecting performance of HESH
- Calibre
- Angle of attack (limited to 65 degree but can function at 60)
- Striking velocity
72
# HESH, HEP-T - REMEMBER THIS QUESTION
Briefly describe how the scab is formed when HESH is used.
When the rebounding tension wave meets further primary shock waves this exceeds the strength of the plate, and a large scab is detached from the rear surface
73
# HESH, HEP-T
List 2 secondary effects of HESH
- Anti-personnel
- Damage to sensitive equipment
74
# BLast Effects and FAE - REMEMBER THIS QUESTION
Explain Reflection of a blast wave
When the blast wave is thrown back at an angle to the original path.
75
# Blast Efffects and FAE
Define Chemical Explosion
The extremely rapid reaction of a chemical system to produce gas and heat.
76
# Blast Efffects and FAE
Define Nuclear Explosion
A sudden release of enormous quantities of
heat by fission or fusion.
77
# Blast Efffects and FAE
Define Physical Explosion
The sudden expansion of gases into a volume much greater than their initial one, accompanied by noise and violent movement.
78
# Attack on personnel - REMEMBER THIS QUESTION
3 factors affecting the energy transfer of fragments
* Fragment mass and velocity.
* Fragment cross sectional area.
* Stability of the fragment.
79
# Attack on Armour - REMEMBER THIS QUESTION
Damage assessment criteria for firepower kill
A tank is knocked out if the main armament is put out of action; either because the crew has been rendered incapable of operating it, or because the armament or its associated
equipment has been damaged, so as to render it inoperative and irreparable by the crew on the battlefield.
80
# Kinectic energy attack on armour - REMEMBER THIS QUESTION
4 ways a designer reduces air resistance when designing KE weapon?
* Small cross-sectional area
* High Mass
* High Velocity
* Aerodynamic design
81
# Attack on Armour - REMEMBER THIS QUESTION
Problems that arise in a combined KE and CE attack
Whilst no fuzing is required to allow the kinetic energy effect to penetrate the armour, the problem of initiating the CE source behind armour presents considerable difficulties to the projectile designer, due mainly to the intense shocks to which any initiating mechanism is subjected on initial impact and during penetration.
82
# Blast Effects and FAE - REMEMBER THIS QUESTION
Explain how burning to detonation occurs
Burning to detonation occurs when there is an abrupt acceleration of the flame front until it becomes a shock wave.
83
# Kinetic energy attack on Armour - REMEMBER THIS QUESTION
What forces are utilised to assist with discarding the sabot?
* Aerodynamic
* Residual gas pressure
84
# REMEMBER THIS QUESTION
Factors affecting VoD of Explosives
* Charge density
* Charge diameter
* Strength of detonator
* Degree of confinement
85
# Attack on Armour - REMEMBER THIS QUESTION
How to reduce spin of a projectile?
- Slipping driving band
- Flute liners
- Spin compensated liners
