An Exact Modal Analysis of the Static Deformation of Long Cylinders and Rings

1984 ◽  
Vol 106 (4) ◽  
pp. 348-353 ◽  
Author(s):  
H. D. Fisher
Keyword(s):  
Continuous Function ◽  
General Solution ◽  
Cross Section ◽  
Thin Shell ◽  
Present Theory ◽  
Angular Variable ◽  
Arbitrary Angle ◽  
Shell Equations ◽  
Modal Solution ◽  
Long Cylinder

This paper presents a static, modal solution of Flugge’s thin shell equations for the cases of a ring or a long cylinder in a state of plane strain. The solution derived here enables the design analyst to compute the deflection resulting from concentrated loads applied in the plane of the cross section at an arbitrary angle to the circumference of the shell and to eliminate the error which results, in certain cases, from employing a previously derived inextensional analysis. A general solution is given for the case of any number of concentrated radial, tangential, and moment loads. The method of analysis for loadings that are a continuous function of the angular variable is also illustrated via a specific example. Numerical results compare solutions obtained with the present theory with those computed by invoking the assumption of inextensional deformation.

Saint–Venant torsion of anisotropic elliptical bar

2017 ◽  
Vol 45 (3) ◽  
pp. 286-294 ◽  
Author(s):  
István Ecsedi ◽  
Attila Baksa
Keyword(s):  
General Solution ◽  
Cross Section ◽  
Elliptical Cross Section ◽  
Elliptical Cross

The object of this article is the Saint–Venant torsion of anisotropic, homogeneous bar with solid elliptical cross section. A general solution of the Saint–Venant torsion for anisotropic elliptical cross section is presented and some known results are reformulated. The case of non-warping cross section is analysed.

The Uniform Flexure of an Incomplete Tore

1949 ◽  
Vol 2 (4) ◽  
pp. 469
Author(s):  
W Freiberger ◽  
RCT Smith
Keyword(s):  
General Solution ◽  
Cross Section ◽  
Harmonic Functions ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Elasticity Problems ◽  
Three Dimensional Elasticity ◽  
Derivatives Of ◽  
Special Case

In this paper we discuss the flexure of an incomplete tore in the plane of its circular centre-line. We reduce the problem to the determination of two harmonic functions, subject to boundary conditions on the surface of the tore which involve the first two derivatives of the functions. We point out the relation of this solution to the general solution of three-dimensional elasticity problems. The special case of a narrow rectangular cross-section is solved exactly in Appendix II.

The linear elastic in-plane bending of curved hollow profiles having a thin-walled rectangular section

1992 ◽  
Vol 27 (3) ◽  
pp. 145-149 ◽  
Author(s):  
F J M Q De Melo ◽  
M A P Vaz
Keyword(s):  
Cross Section ◽  
Thin Shell ◽  
Transverse Section ◽  
Accurate Solution ◽  
Rectangular Section ◽  
Element Analysis ◽  
Linear Elastic ◽  
Graphical Result ◽  
Thin Walled ◽  
Shell Finite Element

This paper presents a simple solution for the flexibility calculation of curved profiles having a rectangular thin-walled cross-section. Some assumptions related to geometric details about the shape of the deformed structure are included in the present analysis, aiming at an economic and accurate solution. Results concerning the distortion of the transverse section are compared with the corresponding data from the solution with a thin shell finite element analysis. A flexibility factor for the structure analysed here is presented as a graphical result.

A Review of Tubular Conical Transition Strength Design Equations

2020 ◽  
Author(s):  
Albert Ku ◽  
Jieyan Chen ◽  
Bernard Cyprian
Keyword(s):  
Thin Shell ◽  
Shell Theory ◽  
Yield Criterion ◽  
Plasticity Theory ◽  
Transition Strength ◽  
Ultimate Capacity ◽  
Design Standards ◽  
Fem Simulations ◽  
Column Type ◽  
Shell Equations

Abstract This paper consists of two parts. Part one presents a thin-shell analytical solution for calculating the conical transition junction loads. Design equations as contained in the current offshore standards are based on Boardman’s 1940s papers with beam-column type of solutions. Recently, Lotsberg presented a solution based on shell theory, in which both the tubular and the cone were treated with cylindrical shell equations. The new solution as presented in this paper is based on both cylindrical and conical shell theories. Accuracies of these various derivations will be compared and checked against FEM simulations. Part 2 of this paper is concerned with the ultimate capacity equations of conical transitions. This is motivated by the authors’ desire to unify the apparent differences among the API 2A, ISO 19902 and NORSOK design standards. It will be shown that the NORSOK provisions are equivalent to the Tresca yield criterion as derived from shell plasticity theory. API 2A provisions are demonstrated to piecewise-linearly approximate this Tresca yield surface with reasonable consistency. The 2007 edition of ISO 19902 will be shown to be too conservative when compared to these other two design standards.

Fluctuating lift and drag on a long cylinder of square cross-section in a smooth and in a turbulent stream

1966 ◽  
Vol 25 (3) ◽  
pp. 481-494 ◽  
Author(s):  
B. J. Vickery
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Circular Cross Section ◽  
Square Cylinder ◽  
Marked Influence ◽  
Fluctuating Pressure ◽  
Scale Turbulence ◽  
Lift And Drag ◽  
Long Cylinder

The paper presents the results of measurements of fluctuating lift and drag on a long square cylinder. The measurements include the correlation of lift along the cylinder and the distribution of fluctuating pressure on a cross-section. The magnitude of the fluctuating lift was found to be considerably greater than that for a circular cross-section and the spanwise correlation much stronger.It was found that the presence of large-scale turbulence in the stream had a marked influence on both the steady and the fluctuating forces. The most significant changes were at small angles of attack (%alpha; < 10°) and included a reduction in base suction and a decrease in fluctuating lift of about 50%.

scholarly journals Approximation of Linear Elastic Shells by Curved Triangular Finite Elements Based on Elastic Thick Shells Theory

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Joseph Nkongho Anyi ◽  
Robert Nzengwa ◽  
Jean Chills Amba ◽  
Claude Valery Abbe Ngayihi
Keyword(s):  
Thin Shell ◽  
Thick Shell ◽  
Absolute Value ◽  
Linear Elastic ◽  
Limit Value ◽  
Shell Equations ◽  
Third Fundamental Form ◽  
Nodal Displacements ◽  
Thick Shells ◽  
Thin Shell Theory

We have developed a curved finite element for a cylindrical thick shell based on the thick shell equations established in 1999 by Nzengwa and Tagne (N-T). The displacement field of the shell is interpolated from nodal displacements only and strains assumption. Numerical results on a cylindrical thin shell are compared with those of other well-known benchmarks with satisfaction. Convergence is rapidly obtained with very few elements. A scaling was processed on the cylindrical thin shell by increasing the ratioχ=h/2R(half the thickness over the smallest radius in absolute value) and comparing results with those obtained with the classical Kirchhoff-Love thin shell theory; it appears that results diverge at2χ=1/10=0.316because of the significant energy contribution of the change of the third fundamental form found in N-T model. This limit value of the thickness ratio which characterizes the limit between thin and thick cylindrical shells differs from the ratio 0.4 proposed by Leissa and 0.5 proposed by Narita and Leissa.

Electron energy distributions in uniform electric fields and the Townsend ionization coefficient

1958 ◽  
Vol 244 (1237) ◽  
pp. 166-185 ◽  
Keyword(s):  
Differential Equation ◽  
Cross Section ◽  
Electric Fields ◽  
Cross Sections ◽  
Collision Cross Section ◽  
Present Theory ◽  
Uniform Electric Field ◽  
Ionization Coefficient ◽  
Special Cases ◽  
Wide Range

The second-order differential equation which expresses the equilibrium condition of an electron swarm in a uniform electric field in a gas, the electrons suffering both elastic and inelastic collisions with the gas molecules, is solved by the Jeffreys or W.K.B. method of approximation. The distribution function F(ε) of electrons of energy ε is obtained immediately in a general form involving the elastic and inelastic collision cross-sections and without any restriction on the range of E/p (electric strength/gas pressure) save that introduced in the original differential equation. In almost all applications the approximation is likely to be of high accuracy, and easy to use. Several of the earlier derivations of F(ε) are obtained as special cases. Using the function F(ε) an attempt is made to relate the Townsend ionization coefficient a to the properties of the gas in a more general manner than hitherto, using realistic functions for the collision cross-section. It is finally expressed by the equation α/ p = A exp ( — Bp/E ) in which A and B are functions involving the properties of the gas and the ratio E/p . The important coefficient B is directly related to the form and magnitude of the total inelastic cross-section below the ionization potential and can be evaluated for a particular gas once the cross-section is known experimentally. The present theory shows clearly the influence of E/p on both A and B, a matter which has not been satisfactorily discussed previously. The theory is illustrated by calculations of F (ε) and a/p for hydrogen over a range of E/p from 10 to 1000. The agreement between the calculated results and recent reliable observations of α/ p is surprisingly good considering the nature of the calculations and the wide range of E/p .

The generation of surface waves over a sloping beach by an oscillating line-source. I. The general solution

1974 ◽  
Vol 76 (3) ◽  
pp. 545-554 ◽  
Author(s):  
Clare A. N. Morris
Keyword(s):  
General Solution ◽  
Integral Representation ◽  
Surface Waves ◽  
Line Source ◽  
Wave Train ◽  
Wave Generation ◽  
Outgoing Wave ◽  
Arbitrary Angle ◽  
Laplace Integral Representation ◽  
Sloping Beach

AbstractThe problem of wave generation by a line source of sinusoidally varying strength situated in water above a beach of arbitrary angle α(0 < α ≤ π) is solved by the use of a Laplace-integral representation of the solution. It is shown that a solution can be constructed which is regular at the shoreline and gives an outgoing wave-train at infinity.

Sign in / Sign up

Export Citation Format

Share Document