SUGGESTED ENERGY EQUIVALENCE APPROACH FOR THE DYNAMIC ANALYSIS OF TAPERED CHIMNEYS

Abstract

In this paper an energy equivalence approach is suggested for the dynamic analysis of tapered chimneys. For any mode of vibration; by equating the kinetic energy of the actual chimney 1o that of an equivalent prismatic chimney, a hypothetical equivalent uniform mass has been obtained for the equivalent chimney. Also, by equating the strain energy of the actual and equivalent prismatic chimney, a hypothetical equivalent constant moment of inertia has been derived for the equivalent chimney .The accuracy of the proposed equivalent prismatic model has been checked by comparing the results with that of the conventional segmented model using the stiffness method, which is deemed to be the more rigorous solution. Free and forced dynamic analyses have been carried out and the results indicated that the proposed equivalence energy model is in a good agreement with the stiffness (segmented chimney) model. The maximum discrepancy in the fundamental natural frequency ranges between 1.2% and 144% The difference in the maximum dynamic bending moment due to wind vortex shedding is about 30%