Experimental investigation of the dynamics of shells of revolution (review)

The results of experimental investigations carried out at the S. P. Timoshenko Institute of Mechanics of the National Academy of Sciences of Ukraine are analyzed in this review. The analysis suggests that experimental investigations of shell dynamics must be contained and developed if the method used to calculate the stressed-strained state and stability of dynamically loaded shells is to be developed further and made more precise. S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev, Ukraine. Translated from Prikladnaya Mekhanika, 35, No. 7, pp. 3–11, March, 1999.     

Stability of imperfect stiffened conical shells

A 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.     

Experimental study of the influence of loading conditions on the stability of rotating cylindrical shells

The effect of the loading conditions on the stability of rotating cylindrical shells is examined experimentally. It is established that the critical loads of axially compressed rotating shells substantially decrease with increasing speed of rotation __________ Translated from Prikladnaya Mekhanika, Vol. 44, No. 6, pp. 93–96, June 2008.     

Experimental studies of the vibrations and dynamic stability of laminated composite shells

The paper discusses the results of systematic experimental studies of vibrations and dynamic instability of thin shells of revolution made of laminated composite materials (glassfiber-reinforced plastics). The basic patterns in the dynamic deformation of shells during natural, forced, and parametric vibrations are considered. The damping parameters of natural vibrations are analyzed. The wave deformation modes of shells subject to periodic excitation are studied. The effect of long-term vibratory loading (torsion) on the dynamic characteristics of three-layer glassfiber-reinforced plastic shells is examined     

Vibrations and buckling of eccentrically loaded stiffened cylindrical shells

The influence of eccentricity of loading on the vibrations and buckling of stringer-stiffened shells is studied. An established nonlinear theory, which takes into account nonlinear prebuckling, is applied and the predictions are compared with experimental results. Two families of shells, one ‘heavily’ stiffened and the other ‘moderately’ stiffened, were tested but detailed results are presented only for the ‘heavily’ stiffened shells. In each family there are three identical shells, each with different eccentricity of loading. In all cases, different in-plane-boundary conditions are considered and correlated with experimental results.     

Resonant electromechanical vibrations of piezoelectric shells of revolution (review)

Scientific results from studies on the resonant electromechanical vibrations of piezoceramic thin-walled shells of revolution, their fragments, and segmented cylinders are analyzed, systematized, and generalized. Considerable attention is focused on experimental studies of resonant vibrations. It is shown that the modes in which deformation occurs inphase throughout the volume are of the highest intensity in all piezoceramic shell structures __________ Translated from Prikladnaya Mekhanika, Vol. 44, No. 4, pp. 3–34, April 2008.