Papers by Keyword: Cylindrical Shell

Abstract: The computer simulation of the dynamic buckling on the cylindrical shell subjected to pulse load was carried out by ABAQUS/Expliect. The value of the rectangle and triangle pulse load is the same and the shape is different, and they are applied on the impact end of the cyclindrical shell. The influence of the load amplitude, the shape of load and the effect of the stress wave on the critical buckling time of cylindrical shell were discussed. The radial displacement curve was obtained which indicates that stress wave propagate along the length of the cylindrical shells, and the curve of strain time history is also acquired which is used to judge bifurcation and give the critical time.

Abstract: With the development of production and technology, the devices of oil refining, chemical, fertilizer and others are progressing to the direction of high parameters (high pressure, high temperature). Pressure vessels must be open, which will made the stress concentration problems more serious, and traditional design methods derived from empirically formula fails to meet the actual demand. In this paper, a theoretical result is calculated with a simplified model of the opening holes in cylindrical shell, verified by a group of solutions got by the ANSYS simulation. And it turns out that the result is rather satisfactory.

Abstract: The cylindrical shells under global bending with different geometric parameters display different failure behavior. The size of typical buckles under axial compressive stress regimes is rather small and extends over a very small zone, with the axial compressive stress reaching the critical value. The first estimate of the elastic buckling strength in bending is the condition in which the most compressed fiber reaches the buckling stress for uniform axial compression. For short cylinders, local bifurcation buckling occurs at the middle of the most compressed side of the shell, and geometric nonlinearity has a little effect on the buckling strength, while for medium-length and long cylinders, the geometric nonlinearity and the ovalization of the cross-section should be considered. This paper explores the failure behavior in elastic cylinders in pure bending.

Abstract: A systematic parametric study was carried out to investigate the elastic and elastic-plastic buckling behaviors of imperfect steel shell subject to axial compression and internal pressure. Studied parameters include the magnitude of internal pressure, steel strength, and ratio of cylinder radius to shell thickness. Design equations were proposed for calculating the elastic and elastic-plastic buckling strength of imperfect steel shells under combination of axial compression and internal pressure. The buckling strength predicated by proposed equations agrees well with that from the numerical simulation.

Abstract: Two coupling models, the fluid-structure coupling and the acoustic-structure coupling, have been studied in this paper, in order to describe the free vibration of a fluid-filled cylindrical shell under internal pressure from two different angles. For both models, a new approach to solve the characteristic equation is presented, using the Galerkin method to obtain the natural frequency of each mode. The comparison shows the results of two models are in good agreement. Although the two models are based on different mechanical theories, the mathematic essences are confirmed to be the same, both derived from Bessel functions.

Abstract: Buckling behavior of functionally graded materials cylindrical shell under pure bending is studied in this paper. The stability equations of functionally graded materials cylindrical shell are derived using the classical plate and shell theory with Kirchhoff hypothesis, importing the bending boundary condition to obtain the critical buckling load. The result shows that the critical moment is linear with the radius, quadratic with the thickness and irrelevant with the length of the cylindrical shell. In addition, the critical moment is decreased by increasing the power law index of the material bulk, trending to a constant finally.

Abstract: The stability of submerged functionally graded (FG) cylindrical shell under hydrostatic pressure is examined in this paper. Based on the Flügges shell theory, the coupled frequency of submerged FG cylindrical shell is obtained, using wave propagation method and Newton method. Then the critical pressure of FG cylindrical shells is given by applying linear fitting method. Results are compared to known solutions, where these solutions exist. The effects of constituent materials, volume fraction, boundary condition and dimensions on the critical pressures of submerged FG cylindrical shell are illustrated by examples.

Abstract: Based on the Donnell’s approximations of the thin shell theory, this paper presents solutions for the problem of free non-axisymmetric vibration of stepped circular cylindrical shells with cracks. The shell under consideration is sub-divided into multiple segments separated by the locations of thickness variations. It is assumed that at the jth step there exists a circumferential surface crack with uniform depth c_j . The influence of circular cracks with constant depth on the vibration of the shell is prescribed with the aid of a matrix of local flexibility. The latter is related to the coefficient of the stress intensity known in the linear fracture mechanics. Numerical results are obtained for cylindrical shells of stepped thickness containing cracks at re-entrant corners of steps. Shells with various combinations of boundary conditions can be analyzed by the proposed method. Furthermore, the influences of the shell thicknesses, locations of step-wise variations of the thickness and other parameters on the natural frequencies are examined. The results can be used for the approximate evaluation of dynamic parameters of cylindrical shells with cracks and flaws.

Abstract: Aiming at the vibration characteristics of cylindrical shell, the different cases of cylindrical shell are analyzed through FEM, and the cases are determined according to the circular angle. The free modality results show that with the same dimension of shell, the modal shape of cases are similar to each other, the frequency increased with the increase of circular angle, but for circular angle (say 90°), the increase trend becomes lower as the frequency difference ratio is lower. In excited vibration analysis, there is a relationship between acceleration peak value and circular angle, which is illustrated by a non-dimension parameter.

Abstract: On the basis of evolutionary structural optimization, the topology optimization for free layer damping cylindrical shell was studied. The checkerboard pattern problem caused by evolutionary structural optimization was solved by discrete independent mesh filter method. The programs of evolutionary structural optimization and discrete independent mesh filter method were made in ANSYS. The optimal topology configuration of free layer damping cylindrical shell was obtained and the effectiveness of Discrete Independent Mesh Filter Method was validated.