Manufacture of one-piece automotive drive shafts with aluminum and composite materials

The natural bending frequency of a torque transmission shaft can be increased without reducing the torque transmission capability if the shaft is made using both carbon fiber composite and aluminum: the former increases the natural bending frequency and the latter sustains the applied torque. The high natural bending frequency of a shaft makes it possible to manufacture the drive shaft of passenger cars in one piece. In this work, a hybrid one-piece drive shaft composed of carbon fiber-epoxy composite and aluminum tube was manufactured by co-curing the carbon fiber on the aluminum tube. The fabricational thermal residual stresses due to the coefficient difference of thermal expansions of aluminum and carbon fiber composite were eliminated by applying a compressive preload to the aluminum tube before the co-curing operation. From the dynamic tests, it was found that the first natural bending frequency and the minimum static torque transmission capability of the hybrid shaft were 9000 rpm and 3550 Nm, respectively, and the shaft did not fail until 10(7) cycles under a dynamic load of +/- 500 Nm. (C) 1997 Elsevier Science Ltd.