COMBAT VEHICLES

Double V-Hulls, Chimneys Seen As Viable Alternatives to Armor

3/1/2011
By Grace V. Jean
The roadside bombs that troops are encountering in Afghanistan are double the size of those they contended with in Iraq. To counter these deadlier threats and newer ones that may turn up, military commanders are scrambling to find technologies that will improve vehicle survivability.

The tried-and-true method has been to add more armor onto vehicles. But material science breakthroughs that would toughen up armor while decreasing its weight are still five to 10 years away, scientists say. That has left officials seeking alternative solutions, such as new passenger cabin designs and methods to vent blasts.

The V-hull design of mine-resistant ambush-protected trucks has proven effective at deflecting acceleration forces from underbelly roadside bomb detonations. Now the Army is pursuing a double V-hull design for its light armored combat vehicles.

The Army has awarded General Dynamics Corp. a contract to build 450 double V-hull Stryker vehicles for delivery during the next 12 months. The technology is a significant survivability upgrade to a passenger cabin floor that was previously flat and armored, said Lt. Col. Jim Schirmer, product manager for the Army’s Stryker Brigade Combat Team.

To meet the aggressive schedule, manufacturer General Dynamics Land Systems is conducting blast testing on the vehicles concurrently with production, said Mike Cannon, senior vice president for ground combat systems.

The first 23 personnel carriers were to be delivered to the Army in January. They will be fielded with the next Stryker brigade combat team deploying to Afghanistan later this year.

The double V-hulls come with blast attenuating seats that prevent lower extremity injuries to passengers.

The company also has developed a counter rocket-propelled grenade “net” to replace the slat armor that adorns current Stryker vehicles. When a rocket-propelled grenade enters the netting, the material digs into the side of the warhead and shorts out the system, said Jim Vickery of General Dynamics. At 1,500 pounds, it is half the weight of the slat armor. That technology is available for future Stryker upgrades, officials said.

Schott Corp., which makes opaque and transparent armor for military vehicles, has developed a glass-ceramic product called Resistan, which withstands extreme temperatures of up to 950 degrees Celsius and remains stable even when subjected to hazardous materials of acidic, alkali or hydrolytic nature.

The Marine Corps, too, has been focusing on pursuing new vehicle designs, such as encapsulated passenger cabins and a chimney-like technology that can vent a roadside bomb blast to mitigate acceleration forces on the hull, said Lt. Gen. George Flynn, commanding general of the Marine Corps Combat Development Command.

A Maryland-based company called Hardwire LLC has developed a “structural blast chimney” that can be integrated onto military trucks. In the event of a blast, the technology allows the explosive energy to vent up and out of the vehicle.

“Think of the blast seeking an outlet, accelerating through the chimney,” Flynn explained to reporters in Washington.

Downward pressure from the supersonic release of energy forces the vehicle back onto the ground.

“You don’t have the rapid acceleration of the vehicle, and the rapid acceleration is what causes the extremity injuries and the core body injuries,” he said.

The chimney was incorporated onto a 7-ton Humvee that survived mine blast testing last fall at Aberdeen Proving Ground, Md.

Mobility is another way to counter the improvised explosive problem, officials said. Efforts to improve engines and suspensions to help tactical trucks and combat vehicles travel off-road on less predictable routes will allow troops to avoid bomb-ridden highways often targeted by insurgents.


Topics: Bomb and Warhead, Improvised Explosive Devices, Combat Vehicles

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