Control of Natural Frequency of Steel Cantilever Beam Using Pretensioning Cable

Sometimes natural frequency of beams is not within the allowable range, regardless of the appropriate shear and bending design. Moreover, every so often structural designers are faced with cases in which it is not possible to increase the beam height due to architectural limitations, or cases in which beam frequency limitation has not been considered during design, and problem of vibration is observed after implementation. Steel cable is utilized in this research to control the natural frequency of beam due to its important advantages such as low weight, small cross-sectional area and high tensile strength. In this study, for the first time, theoretical relation is developed to calculate the increase in pre-tensioning force of steel cable under external loading based on the method of least work. Moreover, the natural frequency of steel cantilever beam without cable and with cable is calculated based on Rayleigh’s method. To verify the theoretical relations, the steel cantilever beam is modeled in the finite element ABAQUS without cable and with cable. The obtained results show that the theoretical relations can appropriately predict the natural frequency of beam. In addition, it is concluded that the pre-tensioning stress of the cable has no effect on the natural frequency.

Keywords:

Natural frequency , Steel cantilever beam , Cable , Pre-tensioning , Rayleigh’s method