[U.S. M1114 up-armored HMMMWV knocked-out by an IED.]
Most improvised explosive devices are probably crudely manufactured and do not dispose of the quality to guarantee a kill. For example, some improvised explosive devices include roadside vehicle-borne bombs15 and others may not be powerful enough. Between January and September 2007 there were twenty-five thousand recorded IED attacks in Iraq, of a total of eighty-one thousand.16 Many of these target Iraqi civilian targets and other attack Coalition personnel, but those relevant to this paper are specifically those designed to defeat Coalition armored fighting vehicles. This threat has led to the recent decision, of the Pentagon, to procure up to 22,000 mine-resistance ambush-protected (MRAP) vehicles, belonging to three different categories.17 To give an idea of the industrial mobilization effort, Force Protection increased production to thirty vehicles per month in mid-2006 and by July 2007 ramped up production up to two hundred per month to fulfill large orders from various clients, including the US Armed Forces and the Iraqi Army. The company’s work force has expanded from 200 people to almost 1,000! The MRAP market has gone from being worth a few hundred million dollars annually to as much as $10 billion a year.18 One of Force Protection’s 16-ton Cougar transport truck was struck by a ninety kilogram bomb, which threw the vehicle’s engine over thirty meters away from the chassis and almost destroy the vehicle in its entirety. Even though MRAP equipment is tested against twelve to twenty kilogram charges, the Cougar’s crew survived the ninety kilogram mammoth improvised explosive device! In mid-January, 2008, one of Navistar’s MaxxPro trucks, crewed by four soldiers, was hit by a ‘very large’ improvised explosive device which sent the vehicle airborne – three of the four passengers survived the attack.19 Navistar is currently supplying the U.S. Armed Forces with 1,900 of its MaxxPro trucks – a deal in May 2007 for 1,200 and a follow-up order in July for another 700 – for a total of $1 billion. Arguably, Navistar’s success is due to the limits of Force Protection’s production capabilities.20
The United States is not the only country beginning to acquire MRAP vehicles. Spain is looking to replace its existing armored fighting vehicle fleet deployed in Afghanistan and Lebanon, with urgency. In late 2007, the Spanish Ministry of Defense decided to acquire forty Light Multirole Vehicles (LMVs) from Iveco, an Italian automotive company, for a total of €14.4 million.21 In January 2008 a decision was made to procure a further forty LMVs, at the risk of slowing down the acquisition of larger MRAP vehicles, for €12.4 million. Furthermore, a third order will be put in soon for another forty vehicles, for the same price tag.22 These vehicles will replace Spain’s indigenous URO VAMTAC, and Spain is looking to acquire a number of Category II MPRA vehicles, as well – either South Africa’s BAE Land Systems OMC’s RG-31 Mk 5, Force Protection’s 16-ton Cougar or Rafael’s Golan.23 Due to the loss of a BMR in Lebanon, and the deaths of three of its passengers, the Spanish Army will also purchase a number of brand-new 8x8 vehicles – to be produced in Spain – and the Ministry of Defense is currently choosing between the Swiss MOWAG Piranha V and the French VBIC.24 Although hardly comparable to the money invested by the United States, Spain is looking at spending between 100 and 140 million euros for 150 urgently required mine protected vehicles, and ultimately procuring around €1 billion worth up to the year 2012.25 However, to better understand the scope and the ambition of the program it should be taken into consideration that the Spanish government has not yet ended production of Spain’s 219 Leopard 2E main battle tanks, considered the most expensive Leopard to be produced to date.26 The program originally cost the Ministry of Defense €1.950 billion for 219 Leopard 2Es and 16 Buffalo armored recovery vehicles (ARVs),27 but costs have spiraled with recent program delays due to the mismanagement of Santa Bárbara Sistemas.28 The Spanish Army is also beginning to accept new Tiger attack helicopters and Pizarro infantry combat vehicles, while the Spanish Air Force is still being issued new Eurofighter Typhoon air superiority fighters. Therefore, the €1 billion should be seen within the context of Spain’s recent military spending in order to understand the urgency of the issue.
[Cut-out image of an IED.]
Aside from the Leopard 2A6M, most tank producing nations have introduced new urban fighting kits with increased protection versus anti-tank mines and improvised explosive devices. Krauss-Maffei Wegmann (KMW) showcased the new Leopard 2 PSO (Peace Support Operation), with add-on turret and hull armor, a secondary remote weapon station near the loader’s hatch, an auxiliary power unit, panoramic 360º coverage by cameras embedded in the vehicle’s hull, an external radio, a searchlight and a dozer blade. Also shown at the Eurosatory 2006 exhibition was France’s AZUR (Action en Zone Urbaine), for Nexter’s Leclerc main battle tank. In the kit, a remote weapon station replaces the commander’s pintle-mounted machine gun, new appliqué composite panels for the side skirts, and added armor to the engine bay, as well as the application of slat armor to protect the entire rear of the vehicle. Perhaps one of the better urban warfare kits is Israel’s new Merkava LIC, which boasts of added all-around protection and increased hull bottom armor thickness. Furthermore, to protect sensitive items against debris, shrapnel and rocks all air intakes, exhausts and electronics are protected by steel mesh, similar to the Leopard 2 PSO. The commander’s cupola is replaced by a new cupola, which allows the commander greater visibility from a higher position and the remote controlled 12.7mm gun is repositioned above the main gun. Interestingly, a new hatch has been introduced in the rear door, to allow snipers to protect the vehicle’s rear. These may equip Israeli Merkava Mk 3s, while the Mk 4 may receive a separate upgrade. This includes two-axis stabilization of the commander’s panoramic sights, with new-generation FLIR and TV channels.34 The Merkava was designed, originally, with a v-shaped hull which was hollow between the bottom of the ‘crest’ and the thinner floor plates above – in the first two models this space was filled with fuel, but in the Mk 3 and Mk4 the fuel tank has been eliminated and instead it’s spaced simply with air.35 On the other hand, some sources indicate that fuel will actually suppress a shaped charge jet (or an explosively formed penetrator) if the fuel tank is self-sealing.36 Perhaps the most well-known urban kit for a main battle tank is the Abram’s TUSK modification package (tank urban survivability kit), which includes a new thermal sight for the loader, a remote weapon station for the tank commander, explosive reactive armor on the side skirts, a rear protecting unit composed of slat armor, a gun shield for the loader and an infantry phone in the rear. It’s possible that these new reactive armor tiles are similar to the Blazer reactive armor tiles applied to the Bradley infantry fighting vehicles and M60A1 main battle tanks in the early 90s.37
[Merkava Mk. 3 LIC; note the sniper hatch in the rear door.]
Hull Bottom Shape & Protection
All new mine resistant ambush protected vehicles have at least one thing in common – a v-shaped hull.42 The v-shaped hull found its first widespread use by South African43 and Namibian44 vehicles operating in Rhodesia, or what is now Zimbabwe. A v-shaped hull refers specifically to the inclination of the floor plates to bulge towards the floor, creating what can be called a wedge (and, is in fact, similar to the ‘wedge armor’ used on the Leopard 2A5, in regards to the inclination of the armored plates). The inclined plates don’t give an anti-tank mine or an improvised explosive device a target with a flat surface area, and so the explosion will follow the path of least resistance and will be deflected away from the vehicle. Naturally, the more inclined the plates the more the blast and the subsequent shockwaves will be deflected and the lesser the impact on the crew of the armored vehicle. The volume between the two inclined plates and the floor plates of the vehicle is normally hollow, or used as a gas tank – such on the Merkava tank (as read above). Generally, due to safety concerns MRAP vehicles leave the volume empty, as the potential protection capability of diesel fuel is arguable. It’s important to note that the inclination of the hull bottom will also result in taller vehicles, and therefore the angle at which the plates are inclined should be juxtaposed against the tactical necessities of the specific vehicle being built. Furthermore, v-shaped hulls will increase the weight of the vehicle and therefore highly inclined plates are difficult to adopt on main battle tanks, or other vehicles with specific weight limits, due to the fact that these are normally already built to the edge of said imposed weight limit and height limit. Normally, this will result in a larger RADAR signature. Finally, another important consideration is that vehicles designed from scratch, with v-shaped hulls, will normally also limit the amount of usable internal volume for passengers and cargo, given the already mentioned limits on weight and height.45
[A line-drawing of the Bushmaster's V-shaped hull.]
Due to the importance of the integrity of the steel plating, low-carbon steels are preferred over harder steels. Therefore, generally, unhardened steel plates are typically superior for these roles, over armored steels with a hardness value of around 40 HRc (Rockwell Hardness Level). Usually, hardened steels don’t retain structural integrity during penetration or when undergoing impact loads.49 The secondary floor plates, or the plating which provides the floor for the passengers above, is now normally being designed as a multi-layer composite armor – using both steel and an energy absorption layer, such as rubber or even ceramic. Much of the technology being developed for lightweight vehicle armors to defeat armor piercing hard-core small-arms ammunition can be applied to anti-mine protection. Due to the importance of transfer of energy, in regards to the transfer of energy of the mine to the crew, energy absorption layers are extremely important. For example, a simple floor armor could be composed of two spaced steel plates, with a layer of another material to absorb impulsive loads. Since impulsive loads normally occur over short periods of time and are characterized as single events when regarding an anti-tank mine (the mine will explode once; secondary waves put aside), the filler layer can stop or slow pressure waves which have transferred through the bottom steel plate.50 Recently, aluminum foam has been suggested for use as the inter-layer material.51 Closed-cell aluminum foam has been found to be superior to rubber since it doesn’t degrade the structural stiffness of the armor and this material also stops or attenuates stress waves moving through the armor.52 Since the performance of ceramics backed by aluminum foam has been found to degrade, as compared to steel, closed-cell aluminum foam refers to the confinement of aluminum foam behind a steel backing-plate for the ceramic.53 In regards to floor armor for an armored fighting vehicle, this might not be relevant given that the chances are that the two confining plates will be composed of steel.
[Knocked-out Cougar - all the occupants survived.]
These materials are just some out of many, and therefore this paper shouldn’t be approached as an exact guide to decide on armor materials. Nonetheless, the information offers a basic picture at what armor designers attempt to achieve when designing lightweight armor which can serve as protection against explosively formed penetrators or shaped charges originating from anti-tank mines or improvised explosive devices. Finally, armor for ballistic protection is likely to spall, which means that the requirement for spall liners along the vehicle’s floor is augmented.
Other Forms of Survivability & Conclusions
A major threat to the crew itself is the shock of the explosive, which may move body parts – such as the neck – in non-ideal ways, which can result in the neck snapping or broken body parts. Therefore, new armored fighting vehicles are introducing new seats, suspending from the hull floor, which better serve to keep a crew member or a passenger fixed in his position in case of an explosion. These seats should have safety belts with at least four to five harness points and the use of suspended foot-rests is advisable to avoid broken ankles.60 Vehicles such as IVECO’s Light Multirole Vehicle (LMV), currently in service with the British Army (as the Panther), Spanish and Italian Armies (as the Lince) and Norwegian army, offer enhanced survivability by separating the crew from the chassis through an armored ‘crew cell’. Wheels, suspension components and the engines are arrayed in such a way that during the blast these fragments will fly in other directions, while the large wheels themselves absorb the energy of the blast, and deflectors installed along the wheel’s arc deflect the blast away from the vehicle.61 These components may increase weight, but the increase in weight is seen as a justified expense given the drastic improvement in survivability. In terms of economic cost, a HMMWV-replacement can cost anywhere between $300,000 and $450,000, while replacements for soldiers will cost anywhere between $200,000 and $1,000,000 (this includes soldiers wounded to the point where they are no longer eligible for combat). The increased price per vehicle is well justified, in other words.
In the future, new technologies will be implemented to increase survivability further, and will help to reduce weight. Such a technology, still in the beginning stages of development, is electric armor. Passive electromagnetic armor – electric armor – is simply two steel plates (or electrodes) spaced apart and attached to an electric battery or generator. When the threat perforates the first plate and touches the second plate a circuit will be completed and the electricity will deform the projectile. This novel armor’s greatest advantage is against long and thin shaped charge jets, as opposed to the thicker improvised explosive devices.62 This armor is bulky and heavy compared to the thinner armor layer composite armors suggested above and requires substantial electric power, to the point where such armor may not be adequate until the advent of a fully electric ground vehicle.63 Nevertheless, it’s an idea of what there is to come in the future.
[New suspended seats introduced in the German Marder 1A5.]
1. Wilson, Clay, Improvised Explosive Devices (IEDs) in Iraq and Afghanistan: Effects and Countermeasures, CRS Report for Congress, 25 September 2006, p. 1.
2. Martínez, Rafael Treviño, Evolución del fenómeno IED y los vehículos protegidos (Parte 1), Fuerza Terrestre, Año III, Vol. 3, Nº 49, p. 10.
3. Wilson, Clay, Improvised Explosive Devices (IEDs) in Iraq and Afghanistan: Effects and Countermeasures, CRS Report for Congress, 25 September 2006, p. 1.
4. Lebanon blast kills UN soldiers, http://news.bbc.co.uk/2/hi/middle_east/6235224.stm
5. Improvised Explosive Devices (IEDs) – Iraq, http://www.globalsecurity.org/military/intro/ied.htm.
7. Eshel, David, Lebanon 2006: did Merkava challenge its match?, http://www.encyclopedia.com/doc/1G1-159390665.html
8. Anti-Armor IEDs are Becoming More Sophisticated, http://www.defense-update.com/features/ ... p_at05.htm
9. Martínez, Rafael Treviño, Evolución del fenómeno IED y los vehículos protegidos (Parte 1), Fuerza Terrestre, Año III, Vol. 3, Nº 49, p. 8.
10. Ferrari, Giorgio, The ‘Hows’ and Whys’ of Armour Penetration, Military Technology, October 1988, pp. 52-55.
11. Chuan, Yu, et. al., Applied Research of Shaped Charge Technology, International Journal of Impact Engineering, Volume 23, 1999, pp. 985-988.
12. Wu, Chun, et. al., Experimental and Numerical Study on the Flight and Penetration Properties of Explosively Formed Penetrators, International Journal of Impact Engineering, Volume 34, 2007, pp. 1147-1162.
13. Horst, Albert W., et. al., Recent Advances in Anti-Armor Technology, American Institute of Aeronautics and Astronautics, 1997, p. 10.
14. Axe, David, Next Step for MRAP, Defense Technology International, November 2007, p. 24.
15. Vehicle Borne IEDs (VBIEDs), http://www.globalsecurity.org/military/ ... ehicle.htm
16. Martínez, Rafael Treviño, Evolución del fenómeno IED y los vehículos protegidos (Parte 1), Fuerza Terrestre, Año III, Vol. 3, Nº 49, p. 11.
17. Candil, Antonio J., Actualidad desde los Estados Unidos: El US Army se equipa con urgencia con nuevos vehículos acorazados, Fuerza Terrestres, Año III, Vol. 3, Nº 47, p. 76.
18. Axe, David, Ramping Up, Defense Technology International, July 2007, p. 23.
19. These two examples are from: Hopes for NY Times Reporting Questioned After MRAP Story, http://www.defenseindustrydaily.com/hop ... ory-04673/.
20. Axe, David, Home Run, Defense Technology International, September 2007, p. 22.
21. Iveco LMV Para el Ejército de Tierra, Fuerzas Militares del Mundo, Año VI, Nº 65, Enero 2008, p. 22.
22. Más Blindados MLV, Fuerzas Militares del Mundo, Año VI, Nº 66, Febrero 2008, p. 74.
24. Vehículos Blindados con Carácter Urgente, Fuerzas Militares del Mundo, Año VI, Nº 64, Diciembre 2007, p. 73.
25. Inteligencia Terrestre, Fuerzas Terrestres, Año III, Vol. 3, Nº 47, p. 6.
26. Candil, Antonio J., Un entorno industrial plagada de dificultades: La fabricación del Carro de Combate Leopard 2E en España (I), Fuerzas Terrestres, Año III, Vol. 3, Nº 49, pp. 38-49.
27. Candil, Antonio J., Leopard 2E MBT Delivery Begins, Military Technology, March 2004, p. 73.
28. Candil, Antonio J., Un entorno industrial plagada de dificultades: La fabricación del Carro de Combate Leopard 2E en España (I), Fuerzas Terrestres, Año III, Vol. 3, Nº 49, pp. 38-49.
29. KMW delivers first LEOPARD 2 A6M to Canada, http://www.epicos.com/epicos/portal/med ... full=false
30. El regreso del carro de combate, Fuerzas Terrestres, Año III, Vol. 3, Nº 47, pp. 15-17.
31. Chuter, Andrew, UK Seeks Lighter Armored Patrol Vehicle, Defense News.
32. Sharman, Alan, Armored Fighting Vehicles Development – A UK Perspective, Military Technology, December 2006, p. 60.
33. ADF to acquire another 250 Bushmasters, http://www.smh.com.au/news/National/ADF ... 18096.html
34. Eshel, David, Armor for Urban Combat, Military Technology, February 2007, pp. 69-72.
35. Gelbart, Marsh, New Vanguard 93: Modern Israeli Tanks and Infantry Carriers 1985-2004, Osprey Publishing, 2004, p. 35.
36. Simpkin, Richard, Tank Warfare: An analysis of Soviet and NATO tank philosophy, Brassey’s, 1979, p. 116.
37. Green, Michael and Stewart, Greg, M1 Abrams at War, Zenith Press, 2005, pp. 106-107.
38. The news Israel wishes we didn't hear, https://www.indymedia.ie/article/65082
39. Huntiller, Mark, Asymmetrical Warfare- Armor, Armada International, June 2004, pp. 38-39.
40. Bianchi, Fulvio, Mine Protection for AFVs, Military Technology, February 2005, p. 39.
41. Toensmeier, Pat, Special Delivery: Marines fast-track new armored vehicles to counter roadside bombs, Defense Technology International, March 2007, p. 26.
42. Axe, David, Breaking the Mold: Diversity adds depth to MRAP, Defense Technology International, October 2007, p. 46.
43. Sparks, Mike, A Crisis of Confidence in Armor?, ARMOR Magazine, March-April 1998, p. 22.
44. Axe, David, One That Got Away: Trade rule bars popular Namibian armored truck from MRAP competition, Defense Technology International, October 2007, p. 20.
45. Bianchi, Fulvio, Mine Protection for AFVs, Military Technology, February 2006, p. 38.
46. Gelbart, Marsh, New Vanguard 93: Modern Israeli Tanks and Infantry Carriers 1985-2004, Osprey Publishing, 2004, p. 39.
47. For example, Soviet/Russian ammunition is two-piece, meaning the propellant is stored in a semi-combustible cartridge apart from the actual ‘warhead’ or round. In Russian tanks, where most of the ammunition is stored in a carousel around the turret ring, it’s irrelevant since the two pieces are stored together – the explosion of the propellant in Iraqi T-72s during the Second Persian Gulf War (1991) and Russian T-80BVs and T-72s in Chechnya is what caused the loss of the turret. Furthermore, in tanks such as the Lince, where the ammunition is stored vertically in a carousel, the ammunition may be inert given the fact that the propellant is stored in the turret. In regards to the loss of the turret, the upward force of an explosion from an improvised explosive device has also caused the loss of a M1 Abrams turret in Iraq, during the occupation.
48. Gelbart, Marsh, New Vanguard 93: Modern Israeli Tanks and Infantry Carriers 1985-2004, Osprey Publishing, 2004, p. 35.
49. Prifti, Joseph, et. al., Improved Rolled Homogenous Armor (IRHA) Steel Through Higher Hardness, Army Research Laboratory, April 1997, p. 1.
50. Nemat-Nasser, S., et. al., Experimental Investigation of energy-absorption characteristics of components of sandwich structures, International Journal of Impact Engineering, Vol. 34, 2007, p. 1120.
51. Hogg, Paul J., Composites for Ballistic Application, Department of Materials, Queen Mary, University of London, p. 10.
52. Gama, Bazle A., et. al., Aluminum foam integral armor: a new dimension in armor design, Composite Structures, Vol. 52, 2001, p. 383.
54. http://z4.invisionfree.com/NSDraftroom/ ... topic=1514
55. Reaugh, J.E., et. al., Impact Studies of Five Ceramic Materials and Pyrex, Journal of Impact Engineering, Vol. 23, 1999, p. 779.
56. Orphal, D.L., et. al., Penetration of Confined Aluminum Nitride Targets by Tungsten Long Rods at 1.5-4.5km/s, Journal of Impact Engineering, Vol. 18, No. 4, 1996, p. 357.
57. Leavy, Brian R., Improved Rolled Homogenous Armor, Army Research Laboratory, March 1996, p. 4.
58. Hazell, Paul J., The Development of Armor Materials, Military Technology, April 2004, p. 59.
60. Bianchi, Fulvio, Mine Protection for AFVs, Military Technology, February 2006, p. 37.
61. Iveco LMV Para el Ejército de Tierra, Fuerzas Militares del Mundo, Año III, Nº 65, 2008, p. 26.
62. Ping, Zheng, et. al., Research on Passive Electromagnetic Armor, IEEE Transactions on Magnetics, Vol. 41, No. 1, January 2005, p. 456.
63. Huntiller, Mark, Asymmetrical Warfare – Armor, Armada International, June 2004, pp. 41-42.