SAVANNAH, GA. The chamber is a huge, yawning insulated chasm big enough to hold a 53-ft. truck trailer—which is exactly what it’s supposed to do. It’s a chamber designed to test how trailers react to both hot and cold temperatures, noted Jay Nelson, supervisor of research and development for Great Dane Trailers.
“Take a combination flatbed trailer with an aluminum deck, for example,” Nelson told FleetOwner here at Great Dane’s multi-product division headquarters, which houses its R&D operations and one of its refrigerated trailer production facilities.
“I’ll put a combo flatbed in here and cool the room down to 40º Fahrenheit, then increase the temperature in 20º increments – to 60º, 80º, then 100º F,” he said. “Over that temperature gradient, the aluminum deck on the combo flatbed is literally going to ‘grow’ or expand a quarter-inch. As a result, you need to factor that phenomenon into your trailer design or you’ll get cracking at the attachment points.”
Great Dane uses a variety of devices to test the durability and longevity of complete trailers and individual components—right down to the aluminum material used in trailer construction. For example, the company uses a “hardness-check” machine to continually make sure the aluminum it receives from suppliers meets tension and compression standards. That machine conducts thousands of tests over the course of a year, Nelson said.
A special “salt fog” machine immerses wheel, landing gear, and other component material samples within its own special laboratory enclosure, then produces seawater grade vapor to gauge rust resistance. “Corrosion is responsible for tremendous amount of damage to trailers today,” Nelson explained. “So we’re constantly testing different kinds of paints, primers, and materials to see how well they resist corrosion.”
On the “brute force” side of the equation, a 200,000-lb. “push-pull” machine tests the strength of steel chains and load bars, Nelson noted. A “main beam” tester exerts 50,000 lbs of force on larger steel and aluminum components. Smaller machines test foam insulation, to see if different compositions insulate better than others for refrigeration purposes.
Another device is the floor tester, which is a giant hydraulic platform that moves section of trailer flooring back and forth underneath two heavy moving wheels to simulate the force exerted by forklifts. “Floors are the most important part of a trailer,” said Nelson. “They affect everything connected to them and must handle a great deal of force—not only from the forklift, but the load it’s carrying as well.”
Finally, there’s the ultimate of ultimates in Nelson’s shop – the Road Simulator, a 53-foot long pit with a tractor fifth wheel at one end, where the trailer is attached, with four moving “pads” on which the trailer’s wheels rest at the other. The pads and fifth wheel are all mounted on hydraulic jacks or cylinders to recreate the stress a trailer will experience on the road.
Here, Nelson and his crew put current trailer models – reefers, flatbeds, and dry vans – as well all the company’s prototypes through their paces; brutal testing that equals 10 years of a trailer’s life out on the road, allowing Great Dane to see how new designs hold up.
“It’s violent – we have big concrete blocks at the bottom of the pit as a safety measure in case the trailer gets shaken off the pads,” he explained. “But it’s a great way to get a clear picture of how well the entire unit – from sidewalls, floors, and doors to axles and landing gear – is going to hold up out there on the highway.”
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