Delivering State-of-the-Art on Schedule

DESIGN, CONSTRUCTION AND PROJECT DELIVERY

The Military Engineer November-December

BY JARROD J. HOOSE, M.SAME, STEPHEN W. ROBERTS JR., AND THOMAS M. BLACK

Before the U.S. Army could research and build the next generation of military ground vehicles, a new facility needed to be built. Designers and engineers from industry and the U.S. Army Corps of En-gineers (USACE) overcame challenges at seemingly every turn to deliver a one-of-a-kind facility on schedule.

The Ground Systems Power and Energy Lab (GSPEL) was built specifically for the Army’s Tank, Automotive, Research, Development and Engineering Center

(TARDEC). Constructed by Walsh Con-struction Co., with on-site construction management from the USACE Detroit District and overall project management from the USACE Louisville District, the 30,000-ft² facility consists of eight sepa-rate laboratories that support and sustain the Army’s combat and tactical ground vehicle systems (see sidebar page 60). Those systems—intended for existing and emerging vehicles—include propul-sion, power generation, energy storage, power management, thermal manage-ment and air filtration. GSPEL’s location, in the heart of metro Detroit’s automotive and engineering technical communities,

makes for a synergistic environment that enhances collaboration.

Because of the unique nature and the precise specifications demanded by GSPEL’s scientists and engineers, the fa-cility’s design and construction presented multiple challenges—many that required solutions on tight deadlines. These trials started before the first spade of dirt was turned and continued throughout.

GSPEL’s “fast-track” process included 13 design phases, requiring constant planning, coordination and adjustments. Ground was broken on the $47 million design-build project in August 2009. Rib-bon cutting took place in April 2012.

Delivering State-of-the-Art on Schedule The new TARDEC Ground Systems Power and Energy Lab will allow the U.S. Army to research, develop

and test the next generation of military ground vehicle systems.


PHOTOS COURTESY TARDEC


The Military Engineer No. 680 63

AN INSIDE LOOKThe facility’s centerpiece is the Power

and Energy Vehicle and Environmental Lab (PEVEL), which boasts an environ-mental chamber and 12 dynamometers used to measure output torque from vehi-cle axles. Among its many advancements, the environmental chamber can generate up to 95 percent relative humidity, create wind speeds up to 60-mph, and simulate temperatures from -60°F up to 160°F.

To create additional heat, the chamber is outfitted with a solar simulation capa-bility that generates up to 1,200-W per M², which is equivalent to the worst so-lar heat on earth. Creating such dramatic temperatures demands huge electrical loads. This capacity, like so much of the facility’s needs, required extensive plan-ning. In fact, there was very little “off-the-shelf ” design for the environmental chamber. Components were custom-de-signed and custom-built. But the lab is ca-pable of accurately mimicking extremely demanding field test conditions in a con-trolled environment. So by consolidating ground environmental testing at a single location the logistical burden is greatly re-duced, which, in the long run, will end up saving time and money.

CHALLENGES EMERGETARDEC had awarded a contract for

the PEVEL dynamometers prior to con-tract award for the overall GSPEL facility, knowing that the design of the machines would be a lengthy process. The manu-facturer then provided 50 percent design drawings at the time of the GSPEL con-tract award. Immediately, however, engi-neers knew they faced a challenge as the dynamometers wound end up being larger than what was represented during the re-quest for proposal process. That forced a redesign of the rooms where they would be housed.

More challenging still was equalizing the lengths of cables running between the dynamometers and their respective motor drives to ensure that data responses sent via electrical pulses would be synchro-nized. Short cables would need to have more slack to equal the longer cables. Yet the larger dynamometer rooms squeezed out any available space on the first floor.

That triggered hasty revisions for a sec-ond-floor mezzanine. A smaller mezza-nine had been planned to hold PEVEL’s environmental chamber machinery; but its size would need to be expanded to accommodate the dynamometer motor drives. The new mezzanine eventually en-compassed the entire area above the sides and front of the chamber.

PEVEL also posed an electrical design challenge. The dynamometers in the lab are regenerative (in other words, their kinetic energy absorbed from the run-ning vehicles produces electric power that can be used or stored). In this case, however, the power produced by the dy-namometers could not be returned to the Detroit Arsenal’s electrical grid. Since the arsenal infrastructure could not meet

GSPEL’s power demands, the lab needed a new electrical feed from a different sub-station. The different power grid meant GSPEL’s regenerative power could not be circulated for re-use by the arsenal.

Designers tried unsuccessfully to work out an arrangement to sell the power to a local electric utility. As it turned out, further calculations determined that the environmental chamber load would al-ways exceed the dynamometers’ electric production capacity. The system would be mostly self-sufficient with no power wasted and no need to export power.

Vibration was another major concern. Engineers knew early on that figuring out how to absorb the powerful vibrations of the dynamometers would be daunting. A large mass was going to be necessary to isolate the vibrations—but the scale of construction was unknown.

When finally completed, the concrete seismic mass under PEVEL would end up being 80-ft-long by 60-ft-wide, and nearly 5-ft-thick. Building it was no simple mat-ter. A train of 60 concrete trucks ran for six straight hours to pour the bottom 4-ft of the mass. The top 9-in required a sepa-rate pour to enable cast-in trenches to be formed accurately for the dynamometer

A large mass was going to be necessary to isolate the

vibrations—but the scale of construction

was unknown.


The Military Engineer November-December 64

translation rails. Concrete was pumped rather than poured to improve convey-ance speed.

ADJUSTING PLANSPEVEL’s dynamometers reside in rooms

adjacent to each side of the environmen-tal chamber. Each room is equipped with three translation rails upon which each dynamometer can move. The rails are 75-ft-long and require alignment to within ten-thousandths of an inch of each other (0.010-in) and between the two dynamometer rooms. The slightest mis-alignment would cause jamming of the translation system drive and clamping system and would prevent the dynamom-eters from moving.

Moreover, the exacting specifications imposed tighter deadlines, some added costs and the need for adaptations on the fly. The HVAC system in the dynamom-eter rooms had to be functional almost a year ahead of normal in order to con-trol the temperature of concrete, rails and grout during the setting phase. Failure to control temperature would have meant uneven setting and a loss of alignment tol-erance. And, the rail alignment required 80 custom-made jigs just to hold the rails in place until the grout set.

During the initial testing of the PEVEL

chamber, an issue arose with regard to the environmental chamber fans used to simulate wind speed. The chamber design had called for specific design pressures and flow rates at temperatures and the se-lected contractor submitted a fan curve meeting all of the requirements. However, once the fans were installed and operat-ing, testing revealed they produced an insufficient flow rate. This resulted in the chamber manufacturer having to replace the three 5-ft-diameter centrifugal fans with three more expensive, but better per-forming, axial fans. This set the project back about three months due to the con-siderable re-work needed in the chamber.

The PEVEL chamber uses a heat trans-fer fluid to move thermal energy between the chamber, chiller and heater. The thin fluid, called Syltherm, is preferred because it can be easily pumped at low tempera-tures and possesses good thermal heat ca-pacity. Those qualities also make it easier for Syltherm to leak. To detect any pos-sible leaks, technicians added dye to the Syltherm. The chamber heat load capac-ity test revealed that the system was not meeting the expected capacity. A blockage in one of the chiller heat exchangers was suspected. An inspection found that the dye was collecting in the heat exchanger and functioning as an insulator.

The Syltherm supplier checked with chemical manufacturers and determined that 10 times the amount of dye needed was added. The solubility of the dye in Syl-therm is reduced significantly at tempera-tures below -20°F, which explains why the dye had collected in the chiller.

Workers cleaned out the heat exchanger, but could not eliminate all of the dye from the system. They operated the chamber at cold temperatures, draining Syltherm near the coldest sections to collect the ex-cess dye in the locations where it would fall out of the mixture. A side-stream fil-tration system was installed to help lower the bulk concentration of dye. These ac-tions ultimately resolved the problem so that the chamber could meet the design requirements and pass its tests.

PROJECT COMPLETEThe turn-key nature of the project was

unique for the USACE Detroit District, with the equipment going into the build-ing being the main focus. While the test-ing and commissioning requirements for the equipment were extensive and very time consuming, in the end, that work re-sulted in a high-quality product.

GSPEL’s grand opening was celebrated as scheduled on April 11, 2012—less than three years after breaking ground. Attend-ees included military and government dignitaries, scientists, and leaders from industry and academia. Those involved in the project demonstrated over a three-year period that such a wide-ranging and complex undertaking demands nothing less than consistent planning, communi-cation and flexibility among key princi-pals and stakeholders. They were up to the task. And the U.S. military, our service-men and women, and the nation’s security will benefit as a result.

Jarrod J. Hoose, M.SAME, is Engineer, and Stephen W. Roberts Jr., is Powertrain Test Engineer, TARDEC. They can be reached at 586-282-4671, or [email protected]; and 586-282-6465, or [email protected], respectively.

Thomas M. Black, is Public Affairs Specialist, USACE Detroit District; 313-226-6750, or [email protected].

GSPEL: WHAT’S INSIDE -

The cen-terpiece lab of the GSPEL facility, it is the point for sub-system integration and complete vehicle system testing.

Enables testing and evaluation of major vehicle electrical systems.

Equipped with three large explosion resistant battery test chambers, it en-ables safe testing of advanced chemis-try battery packs as well as traditional lead-acid batteries.

Enables evaluation of hybrid electric power trains and the development of hybrid motor technology.

Provides capability

for developing and evaluating fuel cell components and jet propulsion fuel reformation systems.

De-signed for testing thermally managed mechanical and electrical components at the test bench scale.

Designed for testing heat exchanging equipment including radiators, charge air coolers and oil coolers.

Capable of test-ing the air flow characteristics of var-ious-sized filter media at four differ-ent flow test benches. Utilizes varying air flows from 250-SCFM to 12,000-SCFM, while using dust feeders to simulate up to four times zero visibility for evaluation of every air filter and air cleaner in the military inventory.

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Delivering State-of-the-Art on Schedule