CompositesWorld
Issue link: https://cw.epubxp.com/i/791367
53 CompositesWorld.com Carbon Composite Driveshaft to take advantage of the higher frequencies between the second, third, fourth and higher resonances. Gorsuch's team addresses these performance factors with a combination of computer modeling, laboratory tests and in-vehicle, on-track testing of driveshafts, for a range of specific applications. "We look closely at each market and develop specific performance goals, whether it is high critical speed, high torque, weight or perhaps durability, and create custom products for each." He cites the example of QA1's driveshaft for dirt track race cars, for which high buckling strength and durability are over- riding concerns. Another product targets street racers who favor much larger engines that produce higher torque, which overpower factory-supplied, two-piece steel driveshafts. Customers also can request a custom-made driveshaft for their specific requirements. Illustration / Karl Reque QA1 Filament Wound Composite Driveshaft › Carbon fiber composite allows customization of shaft's torsional stiffness, axial strength and critical speed. › Composite driveshafts offer up to three times greater strength at half the weight of those made with legacy metals. › Nanosilica-enhanced epoxy resin significantly increases shaft longitudinal and hoop stiffness compared to non-modified epoxy. Beginning at square one To produce a driveshaft, QA1's engineers first input a customer's information — car type, engine type, horsepower and torque, rpm limit, automatic or manual transmission, type of rear suspension setup, and more — into the company's design process. According to Scott Neubauer, QA1's composites engineer for advanced materials, QA1 calculates 12 engineering constants for the thin- walled, tubular driveshaft laminates via a numerical model that is based on a three-dimensional implementation of classical lami- nation theory. e constants are the elastic moduli (Ex, Eθ, Er), the shear moduli (G xθ , G θr , G xr ) and the Poisson's ratios (V xθ , V θr , V xr , V θx , V rθ , V rx ). "Out of these 12 constants, we use the three elastic moduli and three shear moduli to calculate buckling torque, critical speed, Helical fibers (35-55°) increase torsional stiffness Axial (lengthwise) fibers increase critical speed Adhesively bonded end-fitting Variable wall thickness (2.5-8 mm) Variable length (depending on vehicle): 1-1.5m typical Adhesively bonded end-fitting High fiber angles (55-90°) increase buckling torque