VIBRATION ANALYSIS OF ROTATING TRUNCATED CIRCULAR CONICAL SHELLS

Abstract

Shell structures are increasingly being used in many industries and as a consequence, the vibration of cylindrical shell structures has been extensively studied. This has been extended to studies on the vibration of rotating cylindrical shell as there are also engineering applications of rotating shell in industry. A natural progression to studies on the vibration of rotating cylindrical shell structures is to extend it to rotating conical shell structures. This has in fact been done on vibration of stationary conical shells; however extensive search of the literature has thus far shown that few studies on rotating conical shell have been carried out. In this dissertation, comprehensive and systematic studies were undertaken for the free vibration of a rotating thin truncated circular conical shell using two different approaches, namely, an analytical approach based on the Galerkin method and a global approximate numerical technique called the generalized differential quadrature (GDQ) method. The influences of rotating speed, cone angle, geometric properties, material properties, meridional wave number, circumferential wave number, boundary conditions and initial stress on the frequency characteristics are also discussed in detail. For the rotating conical shell, results are presented by the analytical approach to discuss the frequency characteristics of the rotating isotropic, orthotropic and sandwich-type conical shells. The influences of boundary conditions on their frequency characteristics are also given respectively by the same approach. Using the GDQ method, the influences of boundary condition and layered configuration on the frequency characteristics of a rotating sandwich-type conical shell, the influence of orthotropic property on the frequency characteristics of a rotating laminated composite conical shell and the influence of initial stresses on the frequency characteristics of a rotating conical shell are examined. Moreover, the influences of rotating speed, cone angle, geometrical property, meridional and circumferential wave numbers on the frequency characteristics are also given. As a special case of conical shell with zero cone angle, the results are presented to discuss the influence of boundary conditions on the frequency characteristics of rotating cylindrical shell. To validate the accuracy and efficiency of the present analysis, various comparisons are made with those available in open literature with very good agreement being attained. From the present results, many significant conclusions can be drawn which may have a wide range of engineering applications.