Stability of imperfect stiffened conical shells

Abstract

a b s t r a c tA general procedure is developed for stability of stiffened conical shells. It is used for studying the sensitivity behavior with respect to the stiffener configurations. The effect of the pre-buckling nonlinearity on the bifurcation point, as well as the limit-point load level, is examined. The unique algorithm presented by the authors is an extended version of an earlier one, adapted for determination of the limit-point load level of imperfect conical shells. The eigenvalue problem is iteratively solved with respect to the nonlinear equilibrium state up to the bifurcation point or to the limit-point load level.A general symbolic code (using MAPLE) was programmed to create the differential operators based on Donnell's type shell theory. Then the code uses the Galerkin procedure, the Newton-Raphson procedure, and a finite difference scheme for automatic development of an efficient FORTRAN code which is used for the parametric study.

Dynamic Analysis and critical speed of rotating laminated conical shells with orthogonal stiffeners using generalized differential quadrature method

“…Using discrete stiffener theory, the strain energy for the stringer can be written as [22]: (20) where and are torsional stiffness and cross sectional area of the stringer, respectively, with being the number of stringers.…”

“…The energy functional of a stiffened rotating conical shell can thus be written as: (27) Substituting Eqs. (1), (10), (12), (16), (20)(21)(22)(23) and (25) into Eq. (27), followed by applying Hamilton's principle to the energy function yields the matrix relationship below: (28) where the coefficients are differential operators of .…”

“…In Spite of the widespread use of stiffened conical shells as a base structures of many industrial processes such as water crafts, drive shafts of gas turbines, high-speed centrifugal separators, motors and rotor systems, a few researches are found on this field [14][15][16][17][18][19][20][21][22]. Besides, these few researches just focus on non-rotating conical shells and the stiffeners have been modeled using smearing method except the work directed by Talebitooti et al [22].…”

“…Mecitoğlu concentrated on the free vibrations of conical shells with orthogonal stiffeners through the orthotropic material approach [18]. More recently, Goldfeld [19], and Jabareen and Sheinman [20] studied the elastic buckling of stiffened conical shells. Farkas et al analyzed the optimum design of a ring-stiffened conical shell loaded by external pressure with buckling load constraint [21].…”

On the vibration and stability of shear deformable FGM truncated conical shells subjected to an axial load

“…The first studies on the stability and vibration of conical shells were formulated using the classical shell theory (CST), in which use the Kirchhoff-Love hypothesis, i.e., the transverse shear deformations are neglected [1][2][3]. Extensive investigations have been carried out to study the vibration and stability problems of thin homogeneous isotropic conical shell under axial load based on the classic shell theory (CST) [4][5][6][7][8][9][10][11][12][13][14][15][16].…”