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AmmoTech > 2.1.3(2) > Flashcards

2.1.3(2) Flashcards

1
Q

Define Explosion

A

An explosion is the RAPID DECOMPOSITION of energetic material to produce energy (heat) and gas which will lead to violent pressure rupturing of any confining structure

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2
Q

Define Deflagration

A

Is a technical term describing subsonic combustion that usually propagates through thermal conductivity (hot burning material heats below colder layer)

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3
Q

Define Detonation

A

Involves a supersonic exothermic front accelerating through a medium that drives a shock front propagating directly in front of it.

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4
Q

What is Velocity of Detonation? VOD

A

The rate, in metres per second, at which the wave of detonation passes through an EXPLOSIVE SUBSTANCE

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5
Q

VODs

A 
ANFO   4800 m/s
TNT      6950 m/s
CE         7160 m/s
PETN   8300 m/s
RDX      8400 m/s
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6
Q

Factors Affecting VOD

A

Density of charge
Charge diameter
Degree of confinement
Strength of detonator

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7
Q

Burning To Detonation

A

Occurs when there is a abrupt acceleration of the flame front, until it becomes a shock wave and the transformation to a detonation is complete

eg. Explosives confined in a tube, where gases cannot escape
Even unconfined explosives, if in sufficient bulk, may generate sufficient pressure to enable the remaining explosives to detonate

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8
Q

Probability Rule

A

Prob Kill = P Hit x P Reliability x P Lethality

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9
Q

Energy sources available for Ammunition Design

A

KINETIC energy

CHEMICAL energy

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10
Q

What is a Physical explosion

A

The catastrophic rupture of a pressurized gas/vapor-filled vessel by means other than reaction

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11
Q

…

A

…

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12
Q

Problems with KE and CE-combined ammunition?

A

The problem of initiating the CE source behind armour due to the shock on impact onto any initiating mechanism

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13
Q

Personnel - frag velocity is controlled by what factors? (3)

A

Amount of explosive behind wall
Charge density and VOD
Density of wall material

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14
Q

What are the types of Ballistic requirements for KE?

A

Internal ballistics
External ballistics
Terminal ballistics

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15
Q

How does a HESH round work?

A

Detonate HE in contact with armour
Shock wave travels through plate and reflects back
causes a tension wave
The tension wave meet the primary shock wave, resulting in a scab detaching from the rear of the plate

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16
Q

Scab size?

A

1.25 to 1.5 times size of weapon’s diameter

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17
Q

What is Reverse Impact Detonation for HESH?

A

If detonation occurs before the fuze can produce detonation of the filling, the shock wave will be travelling in the wrong direction

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18
Q

Describe how APFSDS works?

A

Shot fired from weapon
Slipping driving bands reduce spin
sabot is discarded through aerodynamic forces
Hits and penetrates through KE

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19
Q

(KE)
What are the 2 forms of stabilisation?
What are the ideal length:diameter ratios of a projectile applying to forms of stabilisation? (x:x)

A

Length:diameter
7:1 spin 15:1 fin(might be angles instead?)

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20
Q

How do Shaped Charges work, IOT defeat armour?

A
  • Achieved by hollowing out the front face of a slab of HE IOT give a conical shape.
  • The energy from the detonation is directed inward and forward as a GASEOUS JET.
  • A metal liner will travel forward with it
  • At an extremely high velocity.
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21
Q

Types of Explosions?

A

Physical (or mechanical)
Chemical
Nuclear

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22
Q

What are Primary Explosives?

Name 3 examples

A

A primary explosive is an explosive substance which is extremely sensitive to stimuli such as heat, friction and/or shock and which requires special care in handling.
Mecury fulminate, Lead Azide, Lead Styphnate

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23
Q

What are Secondary Explosives?

Name 2 examples

A

A secondary explosive is an explosive substance which is relatively insensitive to stimuli such as heat, friction and/or shock. (eDEOP)

RDX, TNT

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24
Q

Requirements for Military Explosives (6)

A
  • Performance
  • Sensitivity
  • Stability & behaviour in storage
  • Water Resistance
  • Consistency
  • Thermal behaviour
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25
Q

Chemical Explosion

A

An extremely RAPID REACTION of a chemical system to produce heat and gas
The sudden expansion of gases into a volume much greater than the initial one, accompanied by noise and violent movement

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26
Q

Nuclear Explosion

A

Sudden release of enormous quantities of heat by fission or fusion processes

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27
Q

Define Blast

Phases?

A
  • 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.
  • Shock Front
  • Positive Pressure Phase
  • Negative Pressure Phase
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28
Q

Dynamic Pressure

Incident Pressure

A

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

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29
Q

Quasi Static Pressure

Reflected Pressure

A

Quasi Static Pressure
-Results when an explosion occurs within a
structure creating 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

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30
Q

2 types of waves created when contacting a surface (2)

What is Mach Stem

A

Reflection
Diffraction
Mach Stem- reflected wave impacts original

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31
Q

Fuel Air Explosives (FAE) - Basic Principle?

A

The basic principle consists of:

creating an aerosol cloud of fuel air mixture, by a bursting charge, which is then detonated to achieve an explosive effect.
The blast wave formed inside the cloud and proceeds unabated to the edge of the cloud

The overpressure is therefore very high when the wave is an appreciable distance from the point of initiation

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32
Q

FAE - Types of Fuel (6)

A
  • acetylene
  • butane
  • ethylene oxide
  • kerosene
  • propylene oxide
  • aluminium
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33
Q

Advantages of FAE (2+)

Disadvantage

A

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-ADV
-Strong winds would prevent the development
of the optimal shape from the initial burst

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34
Q

Types of Targets for FAE (7)

A 
Structures
Concentrations of AFV and SP Guns
Parked aircraft
Minefield clearance
Ships
Bunkers / trenches
Concentrations of troops in the open
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35
Q

Key Target types for target analysis? (3)

A

People
Attack on Armour
Aircraft in Flight

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36
Q

Types of Aircraft targets? (3)

A

Fast Moving
Slow moving
Helicopters

37
Q

Standard Damage Criteria for A/C (6)

Alternate (3)

A 
KK-Kill    immediate
K            10sec
A            5 mins
B            5 hours
C            (mission abort)
E            complete msn, needs repair

F(t) permanently unable to fly
C(t) Unable to continue
E(t) needs to be grounded for repairs

38
Q

Areas of Aircraft Vulnerability (8)

A 
Airframe
Aircrew
Fuel cells
Engines
Power transmission systems
Flight controls
Avionics
Payload
39
Q

Reduction of Vulnerable Areas for A/C (6)

A 
Armouring
Burying sensitive components
Concentrating sensitive components
Duplicating components
Separating Components
Self sealing fuel tanks
40
Q

Types of Warheads against aircraft? (7)

A 
Blast
Fragmentation (Inefficient --80% Wasted)80% Wasted)
Fragmentation plus blast
Special kinetic energy
     -Discrete rod
     -Continuous rod
Shaped charges
Sub--projectiles
Cluster
41
Q

Effects of Altitude (4)

A

Density
Attenuation (weakening of shock wave)
Miss Distance
Altitude increase = Warhead increase

42
Q

Fragmenting Warheads - How much is wasted?

How to make more efficient?

A

> 80% wasted, 50% in wrong direction

Preferential Frag warhead direct the frag in a given direction

43
Q

Pers - Most efficient mode of attack? (3)

A
  • High probability of a hit
  • Rapid transfer of energy
  • No unecessary overkill
44
Q

A WOUND is caused by the transfer of energy from fragment to body. The type of wound is dependent on what? (3)

A
  • Amount of energy transferred
  • The rate of transfer
  • Tumbling/yawing of fragment
45
Q

List the 3 Fragment producers (Frag design)

A
  • Generic HE projectiles.
  • Pre notched containers.
  • Pre formed fragments.
46
Q

Control of the fragments SIZE is ACHIEVED by: (4)

A
  • Case material and its mechanical properties
  • Thickness of the wall
  • Quantity of explosive and its position in relation to
    the fragmenting case
  • VOD of the explosive.
47
Q

What is Fragment VELOCITY controlled by?

A
  • Amount of explosive behind the fragment wall
  • Charge density and velocity of detonation
  • Density of the wall material
48
Q

What are the factors affecting performance of fragmentation? (4)

Describe.

A

DOHA

  1. DISTRIBUTION of frag:
    - Spin rate will influence but not pattern
    - Usually symmetrical on longitudinal axis
    - Angle of arrival
  2. Orientation of projectile
    - Effective distribution when angle is vertical
    - Increasing amount of frag is projected into the air or
    ground as the angle changes
  3. Height of burst
    - 2-4 metres is best
    - achieved by fuzes
  4. Average area of exposed target
    - Target posture
    - Terrain
    - PPE
49
Q

Factors affecting RATE of transfer? (4)

A

Mass
Velocity
Cross sectional area
Stability of the fragment

50
Q
  1. Types of Armour Construction (7)
A

RSPFECS

Rolled homogenous armour
Spaced homogenous
Ply
Face hardened
Explosive reactive armour (ERA)
Composite (Chobham)
Slat (bar)
51
Q

Tank Damage Assessment Criteria

A

M -Mobility kill
F -Firepower kill (incl. main armament, ammo, pers)
K -Completely destroyed

52
Q

APC & MICV (IFV) assessment criteria

A

F - firepower kill

P - payload kill (Pers in the back)

53
Q
  1. List the 3 basic modes / methods of attack to defeat armoured vehicles and fortifications
A

KCC

  • Kinetic energy
  • Chemical energy
  • A combination of both
54
Q

Explain Shot Failure - Barrelling

A

Direct compression failure in the shot material. The
shot bellies at about its mid point

Increase in cross sectional area and the shot fails to
push through.

55
Q

Explain Shot Failure - Shattering

A

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, the shot nose can fail under these stresses and longitudinal cracks are formed

56
Q

Explain Shot Failure - Lateral bending

A


At high angles of attack the shot is subjected to severe lateral stresses, both particularly towards its rear end.

The effects of these stresses can be reduced by increasing the toughness of the shot towards its rear end and by fitting a toughened steel sheath over the rear end of the shot.

57
Q

What are ways to Increase Penetration? (5)

A
  • Lengthening of the BARREL
  • Lengthening the PROJECTILE
  • Rocket Assistance (RA)
  • Improve STEADINESS of shot
  • Use of segments long rod penetrators
58
Q

HEAT - Factors affecting Shape Charges (5)

A
  • Cone diameter
  • Shape of liner
  • Liner material
  • Stand-off distance
  • Rate of spin
59
Q

Chemical Energy - Plate Charges

A 
HEAT versus Plate Charge
(EFP / SFF / Miznay Schardin)
o Manufacture Tolerances
o Greater Stand Off
o Rate of Spin
o Penetration
o Lethality
60
Q

Behind Armour Effects

A

BAE contribute to lethality of attack

Effects may be physical, psychological or physiological

61
Q

What are BAE Effect types? (4)

A

SHOL

Spalling
Heat/fires
Overpressure
Luminescence

62
Q

Methods of weapons/Delivery of shaped Charges (5)

A

GGMAM

  • Guns
  • Grenades
  • Mines
  • Aircraft bombs
  • Missiles
63
Q

Factors taken into consideration in the defeat of armour (3)

A
  • Accuracy
  • Reliability
  • Lethality
64
Q

Description of Kinetic Energy

A

In the form of a solid missile/projectile, which dissipates it’s energy on impact and requires no triggering device to control the energy release.

65
Q

Description of Chemical Energy

A

In the form of a substance, with a considerable potential energy, relative to it’s mass, which can liberate that energy when suitably initiated. Such materials are familiar as HE and the initiation mechanism as the fuze.

66
Q

General Principles of HESH?

A

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

67
Q

HESH Scab size in reference to its diameter?

A

generally 1.25 to 1.5 times its own diameter

Velocity of scab 30 - 130 metres pers sec

68
Q

What is Reverse Impact Detonation (RID)?

A

Detonation occurs before the fuze can produce detonation of the filling,
the shock wave will be travelling in the wrong direction

69
Q

Secondary Effects from HESH? (2)

A

Anti -personnel

Damage to sensitive equipment

70
Q

Types of armour that defeat HESH (4)

A

Spaced armour
Skirting plates
Grooved
Reactive armour

71
Q

HESH has good performance against what other targets?

A
  • Emplacements
  • Pill boxes
  • Concrete Structures
72
Q

Factors affecting Performance of HESH? (3)

A
  • Calibre
  • Angle of Attack
  • Striking Velocity
73
Q

Requirements for:
Internal Ballistics
External Ballistics (4)
Terminal Ballistics (4)

A

High Velocity = a wide base for the propellant to work against and a low mass to overcome

External

  • Small cross sectional area
  • High Mass
  • High Velocity
  • Aerodynamic design
TERMINAL
Small cross sectional area
High mass
High velocity
Hard material
74
Q

Stabilisation Length:diameter ratios for Spin/Fin?

A

Length:Diameter ratio
Spin - 7:1
Fin 15:1

75
Q

What does the following mean?

APCR
APCNR
APFSDS

A
  • Armour Piercing Composite Rigid (APCR)
  • Armour Piercing Composite Non Rigid (APCNR)
  • Armour Piercing Fin Stabilised Discarding Sabot (APFSDS)
76
Q

Parts of a APFSDS (see picture!) (5)

A
  • Centring Band
  • Slipping Driving Band
  • Obturator
  • Sabot
  • Screw Thread
77
Q

What are the two types of discarding sabots?

A

Petal

Pot

78
Q

Developments for KE Projectiles

A 
 Move to DU
           - Self sharpening
           - Pyrophoric effect
 Energetic propellants
 Higher diameter: length ratios
 Higher calibre (up to 140 mm)
 Electromagnetic - hypervelocity projectiles
79
Q

What is a Shape Charge?

A

A charge shaped so as to concentrate its explosive force in a particular direction

80
Q

Parts of a HEAT Round (6) (look at picture!)

A
  • PIBD Fuzing
  • Ballistic Cover
  • Empty Space and Shape Assist
  • Conical Liner
  • Detonator
  • Explosive
81
Q

With a shaped charge the residual energy after penetration lies within what materials? (2)

A
  • Unconsumed part of the jet

- Fragments of metal (spalling)

82
Q

How do shaped charges achieve their effect?

A

Intense concentration of kinetic energy

83
Q

What is the Secondary effect of Shaped Charges?

A

Anti-personnel effects from the fragmentation of the external casing

84
Q

What are the FACTORS affecting the performance of shaped charges? (5)

A
  • Cone diameter
  • Shape of liner
  • Liner material
  • Stand-off distance
  • Rate of spin
85
Q

What are the ideal stand-off distances for shape charges? (2)

A

2 CD - little degradation

5 CD - peak performance

86
Q

Spin Compensation

A

Slipping driving bands
Fluted liners
Spin compensated liners

87
Q

Plate Charges. What are they also known as?

A
  • Miznay-Schardin Effect
  • Plate charge
  • EFP
  • Self forging fragment
88
Q

Initiation methods of Explosives

A 
Direct heat/flame
Percussion and stabbing
Electrical
Shock Waves
Electromagnetic Fields
Laser
Chemical Reaction

AmmoTech (41 decks)

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