scholarly journals The Dynamic Similitude Design of a Thin-Wall Cylindrical Shell with Sealing Teeth and Its Geometrically Distorted Model

2014 ◽  
Vol 7 (2) ◽  
pp. 708902 ◽  
Author(s):  
Zhong Luo ◽  
Yunpeng Zhu ◽  
Qingkai Han ◽  
Deyou Wang
2011 ◽  
Vol 179-180 ◽  
pp. 212-219
Author(s):  
Guo Ping Wang ◽  
Hua Ling Chen ◽  
She Miao Qi ◽  
Jiu Hui Wu ◽  
Lie Yu

Distribution of static interference pressure between a thin-wall flexible cup and a flexible shaft fluctuates heavily along the axis of the cup and is quite different from pressure distribution of common interference styles. In this article, aiming at solving distribution of static interference pressure between a thin-wall flexible cup with much thicker bottom and a hollow flexible shaft, mechanical model and mathematical model of solving the problem were built based on classic thin shell theory. Special difference is that precise special solution of bending equation of thin cylindrical shell was used to substitute the special solution which is original from bending deformation of thin cylindrical shell in no moment status. And a brand new general solution, the relational expression between bending deformation of thin wall of the cup and distribution of the static interference pressure, was obtained. Then, a method used to solve the pressure distribution was presented by solving integral equation and applying superposition principle for the first time. Through using the method to solve an example and comparing calculated results with FEM results, it was proved that the method is correct and effective.


Author(s):  
Z Luo ◽  
YP Zhu ◽  
XY Zhao ◽  
DY Wang

This study investigates the applicability of distortion models for predicting dynamic characteristics of a rotating thin-wall short cylindrical shell. The significance of this study is that it provides a necessary scaling law, applicable structure size intervals, and its boundary functions, which can guide the design of distortion models. Sensitivity analysis and governing equations are employed to establish the scaling law between the model and the prototype. Then a commonly used 7050 aluminum alloy cylindrical shell is analyzed as a prototype. The determination of applicable structure size intervals is discussed, and the boundary functions of the applicable structure size intervals are investigated. The applicability of the scaling law and the applicable intervals of rotating thin-wall short cylindrical shell are verified numerically. The results indicate that distortion models that satisfy the structure size applicable intervals can predict the characteristics of the prototype with good accuracy.


Author(s):  
Dennis Williams

This paper presents the first of a series of solutions to the buckling of imperfect cylindrical shells subjected to an axial compressive load. In particular, the initial problem reviewed is the case of a homogeneous cylindrical shell of variable thickness that is of an axisymmetric nature. The equilibrium equations as first introduced by Donnell over seventy years ago are thoroughly presented as a basis for embarking upon a solution that makes use of perturbation methods. The ultimate objective of these calculations is to achieve a quantitative assessment of the critical buckling load considering the small axisymmetric deviations from the nominal shell wall thickness. Clearly in practice, large diameter, thin wall shells of revolution that form stacks (as found in flue gas desulphurization absorber assemblies) are never fabricated with constant diameters and thicknesses over the entire length of the assembly. As such, ASME Boiler and Pressure Vessel Code Section VIII fabrication tolerances as supplemented by ASME Code Case 2286-1 are reviewed and addressed in light of the findings of the current study and resulting solutions with respect to the critical buckling loads. The method and results described herein are in stark contrast to the “knockdown factor” approach currently utilized in ASME Code Case 2286-1. Recommendations for further study of the imperfect cylindrical shell are also outlined in an effort to improve on the current design rules regarding column buckling of large diameter shells designed in accordance with ASME Section VIII, Divisions 1 and 2; and ASME STS-1 in combination with the suggestions contained within Code Case 2286-1.


Author(s):  
Gurinder Singh Brar ◽  
Yogeshwar Hari ◽  
Dennis K. Williams

This paper presents the third of a series of solutions to the buckling of imperfect cylindrical shells subjected to an axial compressive load. In particular, the initial problem reviewed is the case of a homogeneous cylindrical shell of variable thickness that is of an axisymmetric nature. The equilibrium equations as first introduced by Donnell over seventy years ago are discussed and reviewed in establishing a basis for embarking upon a solution that utilizes finite difference methods to solve the resulting equilibrium and compatibility equations. The ultimate objective of these calculations is to achieve a quantitative assessment of the critical buckling load considering the small axisymmetric deviations from the nominal cylindrical shell wall thickness. Clearly in practice, large diameter, thin wall shells of revolution that form stacks are never fabricated with constant diameters and thicknesses over the entire length of the assembly. The method and results described herein are in stark contrast to the “knockdown factor” approach currently utilized in ASME Code Case 2286-1. The results obtained by finite difference method agree well with those published by Elishakoff and Williams for the prediction of buckling load.


2016 ◽  
Vol 2016 ◽  
pp. 1-22 ◽  
Author(s):  
Qiansheng Tang ◽  
Chaofeng Li ◽  
Bangchun Wen

Forced vibration of thin-wall cylindrical shell under nonlinear boundary condition was discussed in this paper. The nonlinear boundary was modeled as supported clearance in one end of shell and the restraint was assumed as linearly elastic in the radial direction. Based on Sanders’ shell theory, Lagrange equation was utilized to derive the nonlinear governing equations of cylindrical shell. The displacements in three directions were represented by beam functions and trigonometric functions. In the study of nonlinear dynamic responses of thin-wall cylindrical shell with supported clearance under external loads, the Newmark method is used to obtain time history, frequency spectrum plot, phase portraits, Poincare section, bifurcation diagrams, and three-dimensional spectrum plot with different parameters. The effects of external loads, supported clearance, and support stiffness on nonlinear dynamics behaviors of cylindrical shell with nonlinear boundary condition were discussed.


2020 ◽  
Vol 3 (151) ◽  
Author(s):  
S.I. Gerasimov ◽  
V.A. Kuzmin ◽  
V.A. Kikeev ◽  
N.A. Trepalov ◽  
V.S. Rozhentsov

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Dennis K. Williams ◽  
James R. Williams ◽  
Yogeshwar Hari

This paper presents the first of a series of solutions to the buckling of imperfect cylindrical shells subjected to an axial compressive load. The initial problem is the case of a homogeneous cylindrical shell of variable thickness that is of an axisymmetric nature. The equilibrium equations as first introduced by Donnell over 70 years ago are thoroughly presented as basis for a solution employing perturbation methods. The ultimate objective of these calculations is to achieve a quantitative assessment of the critical buckling load considering the small axisymmetric deviations from the nominal shell wall thickness. Clearly in practice, large diameter thin wall shells of revolution that form stacks (as found in flue gas desulphurization absorber assemblies) are never fabricated with constant diameters and thicknesses over the entire length of the assembly. As such, ASME Boiler and Pressure Vessel Code Section VIII shell thickness tolerances as supplemented by ASME Code Case 2286-1 are reviewed and addressed in comparison to the resulting solutions with respect to the critical buckling loads. The method and results described herein are in stark contrast to the “knockdown factor” approach currently utilized in ASME Code Case 2286-1. Recommendations for further study of the imperfect cylindrical shell are also outlined in an effort to improve on the current rules regarding column buckling of large diameter shells designed in accordance with ASME Section VIII, Divisions 1 and 2 and ASME STS-1 in combination with the suggestions contained within Code Case 2286-1.


2012 ◽  
Vol 226-228 ◽  
pp. 1604-1608
Author(s):  
Xiang Lin Jiang ◽  
Dong Bing Zhang ◽  
Han Bin Yi

This paper based on the structural characteristics of thin-wall steel truss of JiuJiang Yangtze River Bridge, designs a distorted model that thickness ratio is 1/10 and the length ratio is 1/40.Through the static test model, the cross-section stress of hangers chord, diagonal and the deflection of corresponding test point is tested, and the result is compared with numerical simulation result. It shows that the result of the test and numerical simulation satisfy the similar relations, thus verifying that the design of scale model is reasonable and correct.


2011 ◽  
Vol 2-3 ◽  
pp. 1021-1026
Author(s):  
Yu Wang ◽  
Hai Yang Duan ◽  
Gao Ming Qin ◽  
Zhong Luo ◽  
Qing Kai Han

Natural frequencies are calculated for a short cylindrical shell based on semi-analytical method of transfer matrix, especially considering the structural effects of sealing teeth. The thin wall shell with some sealing teeth can be divided into finite segments where the diameters are different. According to the theory of the state vector expression of a structure cross-section, a first-order ordinary differential equation referring to state vectors of continuous segment sections of a short cylindrical shell is established based on governing equations of thin cylindrical shell. Then a total transfer matrix of the shell with sealing teeth is obtained after producing all the transfer matrices of all the segments. The boundary conditions investigated in the study are free-free, free-clamped and clamped-clamped of the two ends of the shell. The natural frequencies can be solved by precise integration of the differential equation of the whole shell with divided segments. The obtained numerical examples show that the sealing teeth have influence on the frequency values of higher circumferential modes, and they also have influence on the natural frequencies in different boundary conditions. The results by the proposed method are also compared with those of finite element method.


Sign in / Sign up

Export Citation Format

Share Document