Dynamic stability of rotating composite shafts under periodic axial compressive loads

This paper describes the dynamic behavior of a rotating composite shaft subjected to axial periodic forces using the finite element method. Laminated composite shafts are modelled using Timoshenko beams. The numerical results show good agreement with the reported beams models. Effects of static and time dependent components of axial loads on the stability of the composite shaft are studied. This paper also investigates the effect of the rotational speeds and the disk on the unstable regions of the shaft. The numerical results show that for the same geometric parameters, a steel shaft has a lower frequency than that of the composite shafts; however, the steel shaft is more stable than composite shafts because the shaft-disk system is subjected to axial periodic forces at lower rotational speeds. Also, the effect of the gyroscopic moments makes the steel shaft more sensitive to the periodic axial load than the composite one.