Application of Finite-Element Method to Interstiffener Buckling in Submersible Cylindrical Hulls

1983 ◽  
Vol 27 (04) ◽  
pp. 281-285
Author(s):  
K. Rajagopalan ◽  
C. Ganapathy Chettiar
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Program ◽  
Cylindrical Shells ◽  
Geometric Stiffness ◽  
Stiffness Matrices ◽  
Finite Element Procedure ◽  
Stepwise Variation ◽  
Thin Walled

A finite-element procedure for the determination of buckling pressure of thin-walled cylindrical shells used in ocean structures is presented. The derivation of the elastic and geometric stiffness matrices is discussed in detail followed by a succinct description of the computer program developed by the authors during the course of this study for the determination of the buckling pressure. Particular attention is paid to the boundary conditions which strongly influence the buckling pressure. Applications involving the interstiffener buckling in submersible hulls and cylindrical shells with stepwise variation in wall thickness are considered and the results compared with the solutions and procedures available in the literature.

scholarly journals Local Elastic and Geometric Stiffness Matrices for the Shell Element Applied in cFEM

2017 ◽  
Author(s):  
Dávid Visy ◽  
Sándor Ádány
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shell Element ◽  
Numerical Examples ◽  
Geometric Stiffness ◽  
Stiffness Matrices ◽  
Plane Element ◽  
Unusual Combination ◽  
Shell Finite Element ◽  
Lagrange Strain

In this paper local elastic and geometric stiffness matrices of ashell finite element are presented and discussed. The shell finiteelement is a rectangular plane element, specifically designedfor the so-called constrained finite element method. One of themost notable features of the proposed shell finite element isthat two perpendicular (in-plane) directions are distinguished,which is resulted in an unusual combination of otherwise classicshape functions. An important speciality of the derived stiffnessmatrices is that various options are considered, whichallows the user to decide how to consider the through-thicknessstress-strain distributions, as well as which second-order strainterms to consider from the Green-Lagrange strain matrix. Thederivations of the stiffness matrices are briefly summarizedthen numerical examples are provided. The numerical examplesillustrate the effect of the various options, as well as theyare used to prove the correctness of the proposed shell elementand of the completed derivations.

The Natural Frequency of the Shape Memory Alloy Anti-Symmetric Angle-Ply Composite Plates Using Finite Element Method

2014 ◽  
Vol 695 ◽  
pp. 52-55 ◽  
Author(s):  
Z.A. Rasid
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Geometric Stiffness ◽  
Stiffness Matrices ◽  
Element Method

Shape memory alloy (SMA) wires were embedded within laminated composite plates to take advantage of the shape memory effect (SME) property of the SMA. Active modal modification of SMAC plates was studied using the finite element method (FEM). A linear FEM formulation was developed based on the first order shear deformation theory. The effect of SMA was captured by adding the geometric stiffness matrix to the stiffness matrices of composite plates. Two methods of frequency improvements are considered here: The active property tuning (APT) and the active strain energy tuning (ASET) methods. The values of recovery stress for the ASET analysis were determined from Brinson’s model. The effects of several parameters on the natural frequencies of the SMAC plates were studied. It was found that the effect of SMA is similar for couples of frequency modes where frequencies of mode I and IV seems to have affected the most by SMA.

Non-Linear Dynamic Analysis of Cylindrical Shells Subjected to a Flowing Fluid

2000 ◽  
Author(s):  
A. A. Lakis ◽  
A. Selmane ◽  
C. Dupuis
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shell Theory ◽  
Cylindrical Shells ◽  
Empty Shell ◽  
The Finite Element Method ◽  
Linear Dynamic ◽  
Stiffness Matrices ◽  
Non Linear ◽  
Element Method

Abstract A theory is presented to predict the influence of non-linearities associated with the wall of the shell and with the fluid flow on the dynamic of elastic, thin, orthotropic open and closed cylindrical shells submerged and subjected to an internal and external fluid. The open shells are assumed to be freely simply-supported along their curved edges and to have arbitrary straight edge boundary conditions. The method developed is a hybrid of thin shell theory, fluid theory and the finite element method. The solution is divided into four parts. In part one, the displacement functions are obtained from Sanders’ linear shell theory and the mass and linear stiffness matrices for the empty shell are obtained by the finite element procedure. In part two, the modal coefficients derived from the Sanders-Koiter non-linear theory of thin shells are obtained for these displacement functions. Expressions for the second and third order non-linear stiffness matrices of the empty shell are then determined through the finite element method. In part three a fluid finite element is developed, the model requires the use of a linear operator for the velocity potential and a linear boundary condition of impermeability. With the non-linear dynamic pressure, we develop in the fourth part three non-linear matrices for the fluid. The non-linear equation of motion is then solved by the fourth-order Runge-Kutta numerical method. The linear and non-linear natural frequency variations are determined as a function of shell amplitudes for different cases.

Stress Analysis of a Tire Under Vertical Load by a Finite Element Method

1977 ◽  
Vol 5 (2) ◽  
pp. 102-118 ◽  
Author(s):  
H. Kaga ◽  
K. Okamoto ◽  
Y. Tozawa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Program ◽  
Temperature Rise ◽  
Strain Energy ◽  
Internal Stresses ◽  
Vertical Load ◽  
The Finite Element Method ◽  
Internal Temperature ◽  
Element Method

Abstract An analysis by the finite element method and a related computer program is presented for an axisymmetric solid under asymmetric loads. Calculations are carried out on displacements and internal stresses and strains of a radial tire loaded on a road wheel of 600-mm diameter, a road wheel of 1707-mm diameter, and a flat plate. Agreement between calculated and experimental displacements and cord forces is quite satisfactory. The principal shear strain concentrates at the belt edge, and the strain energy increases with decreasing drum diameter. Tire temperature measurements show that the strain energy in the tire is closely related to the internal temperature rise.

Post-buckling inelastic analysis of thin-walled metal members using the Generalised Beam Theory

2019 ◽  
Author(s):  
Miguel Abambres ◽  
Dinar Camotim ◽  
Miguel Abambres
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Beam Theory ◽  
Flow Theory ◽  
Promising Alternative ◽  
Inelastic Analysis ◽  
Post Buckling ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Generalised Beam Theory

A 2nd order inelastic Generalised Beam Theory (GBT) formulation based on the J2 flow theory is proposed, being a promising alternative to the shell finite element method. Its application is illustrated for an I-section beam and a lipped-C column. GBT results were validated against ABAQUS, namely concerning equilibrium paths, deformed configurations, and displacement profiles. It was concluded that the GBT modal nature allows (i) precise results with only 22% of the number of dof required in ABAQUS, as well as (ii) the understanding (by means of modal participation diagrams) of the behavioral mechanics in any elastoplastic stage of member deformation .

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