MAIDEN VOYAGE


The forged aluminum hull, affixed to a massive test rig, undergoes an objective-level underbody blast test. The test, conducted in October 2014, resulted in minimal hull deformation. (U.S. Army photo)


collaborative effort provided experts at the U.S. Army Training and Doctrine Command ( TRADOC) Maneuver Cen- ter of Excellence (MCOE) with data to write requirements for underbody blast protection.


Te APOT ManTech project advanced lower hull manufacturing technologies for


aluminum-hulled combat vehicles


and provided a better means of maturing several structural features for validation and incorporation into the Armored Multi-Purpose Vehicle. Te program achieved these results—and received the 2017 Defense Manufacturing Tech- nology Achievement Award—through cooperation across multiple agencies, programs and even nations.


INADEQUATE PROTECTION Aluminum-hulled combat vehicles histor- ically have been vulnerable to underbody blasts. Fielded in the 1960s, both the M113 Armored Personnel Carrier (APC) and M551 Airborne Reconnaissance Assault Vehicle were required to be air- droppable, which restricted their weight and corresponding aluminum armor


Fielded in 1981, the M2 and M3 Brad- ley Infantry Fighting Vehicles featured a lower hull similar in design and armor thickness to the M113 APC, with the exception of an additional steel armor plate under the front third of the vehicle. It too proved vulnerable to underbody blasts, in this case IEDs in Operation Iraqi Freedom, so a steel add-on armor kit


for the Bradley was fielded expedi-


ently. However, when this configuration was tested by the Office of the Secretary of Defense Live Fire Test and Evalua- tion (OSD LFT&E) program in 2012, the results indicated “severe vehicle and occupant vulnerabilities.” OSD’s evalu- ation set the foundation for the APOT effort, which began in 2012.


thicknesses. Requirements writers at the time deemed anti-tank mine resistance to be impractical for air-droppable vehicles; therefore, these vehicles were developed with only a modicum of blast resistance, equivalent to an anti-personnel mine. Teir vulnerability to underbody blast events soon became evident when they were deployed in Vietnam.


HARNESSING OF EFFORTS Te APOT ManTech effort sought to mature more


effective manufacturing


methods to provide protection not only from typical conventional underbody blast devices, but from blasts many times the power of a typical IED explosion (defined as objective level) and signifi- cantly more than the amount of explosive used in the OSD LFT&E evaluation of the Bradley. In after-action accounts of hull failures caused by large underbody blasts, battle damage assessments noted that hulls failed because of welds rup- turing and the relatively thin aluminum belly plates fracturing.


To mitigate these failures, APOT sought to


fabricate thicker aluminum hulls


using fewer welds. Specifically, APOT matured the forging of a monolithic alu- minum hull; the forming of a hull from thick aluminum plate; and the welding of thick aluminum plate using high ener- gies, which reduces the number of weld passes by up to 90 percent as compared with typical hand welds. Industrial part- ners for these efforts were Alcoa Defense with Alcoa Forgings and Extrusions (now


ASC.ARMY.MIL 209


SCIENCE & TECHNOLOGY / DASA(R&T)


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