In this era of increasingly stringent fuel economy requirements, reducing overall vehicle mass has taken on a pivotal role in the design process. Among its host of weight-saving measures, the 2014 Chevrolet Corvette introduces one notable example of this "light thinking" in the form of a new shape memory alloy material that was developed by General Motors. Generally made from copper-aluminum-nickel or nickel-titanium, shape memory alloys are classified as "smart materials" due to their unique ability to change shape, strength, and/or stiffness when activated by heat, stress, a magnetic field or electrical voltage and then return to their original configuration when that external input ends.
On the new Corvette, the shape memory alloy application takes the form of a wire that replaces a conventional actuator motor to open a rear hatch vent any time the car's deck lid is raised. When energized by an electrical current, the shape memory wire contracts, activating a lever arm that opens the vent reducing internal air pressure and allowing the trunk lid to be closed more easily. Once the hatch is closed, the electrical current ceases, and the wire returns to its original shape, a change that closes the vent to maintain cabin temperature. According to Chevy, opting for this "smart" solution saved approximately 1.1 pounds from the total system's weight compared to a normal motorized installation. If that's not sufficient enticement, this high-tech alternative also is less expensive.
"The shape memory alloy used on the new Corvette represents nearly five years of research and development work on smart materials for which GM has earned 247 patents," said Paul Alexander, GM smart materials and structures researcher. "And it is just the beginning. We have many more smart material applications in the pipeline that will bring even more improvements to our vehicles going forward."
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