Chapter 5 explores the torsion and bending of driveshafts made of composite. The driveshaft is modeled as an anisotropic rod with a solid or thin‐walled tubular cross‐section. The dominant load on the driveshaft is torque that causes high shear stress in the material. The alternating torque also causes twist vibration modes. The secondary loads are bending and tension. The resulting stresses from secondary loads are usually moderate but can provoke Greenhill's torque instability and bending vibration modes. From the lightweight viewpoint, the advantageous design of driveshafts is the thin‐walled tubular structure. The corresponding model of a thin‐walled anisotropic driveshaft is based on the kinematic hypotheses and equations of thin anisotropic shells. The kinematic hypotheses assume that the normal cross‐section profile of a thin‐walled shaft is not distorted but instead is only rotated and displaced in space. Using kinematic hypotheses, the strains and curvatures of the middle surface of the shaft are displayed. Strain equations are obtained by varying the potential energy functional of the classical theory of anisotropic shells. Finally, the problem of determining the critical load for a thin‐walled driveshaft in axial compression is investigated. The proposed model is appropriate for analysis of driveshafts made of multilayered composite materials. As mentioned, elongated driveshafts are subjected to Greenhill's twist buckling. If twist instability occurs, the straight axis of twisted rod transforms to the helical spiral curve. This motivates the pursuit for the optimal cross‐sectional shape of a driveshaft. Remarkably, the optimal shape of cross‐section of a shaft for the maximal critical torque is a hollow triangle. On the contrary, circular hollow cross‐section leads to the minimum shear stress under given torque. Accordingly, the short driveshafts preferably must have a circular hollow cross‐section, while lengthy driveshafts should have a triangular hollow form of profile.
Optimization of Composite Driveshaft
13.05.2019
25 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
Kraftfahrwesen | 1989
|SAE Technical Papers | 1989
|Composite driveshaft survived race
Kraftfahrwesen | 1980
|