scholarly journals An 8-Node Shell Element for Nonlinear Analysis of Shells Using the Refined Combination of Membrane and Shear Interpolation Functions

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Woo-Young Jung ◽  
Sung-Cheon Han
Keyword(s):  
Finite Element ◽  
Shear Deformation Theory ◽  
Shell Element ◽  
Element Model ◽  
Shell Elements ◽  
Numerical Examples ◽  
Plates And Shells ◽  
Shell Finite Element ◽  
Assumed Natural Strain ◽  
Interpolation Functions

An improved 8-node shell finite element applicable for the geometrically linear and nonlinear analyses of plates and shells is presented. Based on previous first-order shear deformation theory, the finite element model is further improved by the combined use of assumed natural strains and different sets of collocation points for the interpolation of the different strain components. The influence of the shell element with various conditions such as locations, number of enhanced membranes, and shear interpolation is also identified. By using assumed natural strain method with proper interpolation functions, the present shell element generates neither membrane nor shear locking behavior even when full integration is used in the formulation. Furthermore, to characterize the efficiency of these modifications of the 8-node shell finite elements, numerical studies are carried out for the geometrically linear and non-linear analysis of plates and shells. In comparison to some other shell elements, numerical examples for the methodology indicate that the modified element described locking-free behavior and better performance. More specifically, the numerical examples of annular plate presented herein show good validity, efficiency, and accuracy to the developed nonlinear shell element.

Nonlinear transient and thermal analysis of functionally graded shells using a seven-parameter shell finite element

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Miguel Gutierrez Rivera ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Shear Deformation Theory ◽  
Shell Element ◽  
Element Model ◽  
Functionally Graded ◽  
Plates And Shells ◽  
Shell Finite Element ◽  
Transient Thermal

AbstractIn this paper the thermo-mechanical response of functionally graded plates and shells is studied using a continuum shell finite element model with high-order spectral/hp basis functions. The shell element is based on the seven-parameter first-order shear deformation theory, and it does not utilize reduced integration or stabilization ideas and yet exhibits no locking. The static and dynamic response of functionally graded shells, with power-law variation of the constituents, under mechanical and thermal loads is investigated by varying the volume fraction of the constituents. Numerical results for deflections and stresses are presented and compared with available analytical and finite element results from the literature. The performance of the shell element for transient thermal problems is found to be excellent.

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.

Quick Aeromechanical Assessment of Turbine Blades Based on Shell Element Based Models

2014 ◽  
Author(s):  
Suryarghya Chakrabarti ◽  
Letian Wang ◽  
K. M. K. Genghis Khan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Computation Time ◽  
Shell Element ◽  
Element Model ◽  
Shell Elements ◽  
Barrier Coating ◽  
Order Of Magnitude

A fast finite element model based tool has been developed to calculate the natural frequencies of fundamental modes of cooled gas turbine bladed disk assemblies during conceptual design. The tool uses shell elements to model the airfoil, shank, and disk, and achieves order of magnitude reduction in computation time allowing exploration of a wide design space at the preliminary design stages. The analysis includes prestress effects due to centrifugal loading and approximate temperature loading on the parts. Sensitivity studies are performed to understand the relative impact of design features such as airfoil internal geometry, bond coat, and thermal barrier coating on the system natural frequencies. Critical features are selected which need to be modeled to get an accurate natural frequency estimate. The results obtained are shown to be within 5% of the frequencies obtained from a full-fidelity finite element model. A case study performed on seven blade designs illustrates the use of this tool for quick aeromechanical assessment of a large number of designs.

Evaluating the Effect of Nozzle Weld Stiffness When Using Shell Finite Element Models for ASME Code Evaluations

2012 ◽  
Author(s):  
Bryan Dunlap ◽  
Hassan Ziada ◽  
John Julyk
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Shell Element ◽  
Finite Element Models ◽  
Shell Elements ◽  
Asme Code ◽  
Section Viii ◽  
Shell Finite Element ◽  
Code Compliance ◽  
Division 2

Typically the use of SHELL finite elements to model nozzle/vessel interfaces will not include details of the weld at the interface. The omission of the weld details from SHELL element models is due to the difficulty in implementing such details and the assumption that additional interface stiffness due to the weld will have a negligible effect on results at locations of interest for Code evaluation. This study will demonstrate a proposed method for modeling weld details with SHELL elements and then evaluate the magnitude of the weld stiffness effect on results and Code compliance. The method of modeling the weld details with SHELL elements used in this study will follow the guidance provided by ASME BPVC Section VIII, Division 2, Annex 5.A [2] for such interfaces. Models of nozzle/vessel interfaces will be shown comparing results of SOLID element models with and without the weld detail, and then SHELL element models both with and without the weld detail. The results from these models will be evaluated and recommendations for future modeling and evaluation of nozzle/shell interfaces with SHELL elements will be offered.

Shell Finite Elements for the Analysis of Multifield Problems in Multilayered Composite Structures

2016 ◽  
Vol 828 ◽  
pp. 215-236 ◽  
Author(s):  
Maria Cinefra ◽  
Erasmo Carrera
Keyword(s):  
Finite Element ◽  
Composite Structures ◽  
Single Layer ◽  
Shell Element ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Multilayered Plates ◽  
Plates And Shells ◽  
Elasticity Solutions ◽  
Shell Finite Element

This paper deals with the analysis of layered structures under thermal and electro-mechanical loads. Constitutive equations for multifield are considered and the Principle of Virtual Displacements (PVD) is employed to derive the governing equations. The MITC9 shell finite element based on the Carrera's Unified Formulation (CUF) has been applied for the analysis. The models grouped in the CUF have variable through-the-thickness kinematic and they provide an accurate distribution of displacements and stresses along the thickness of the laminate. The shell element has nine nodes and the Mixed Interpolation of Tensorial Components (MITC) method is used to contrast the membrane and shear locking phenomenon. The finite element analysis of multilayered plates and shells has been addressed. Variable kinematics, as well as layer-wise and equivalent single layer descriptions, have been considered for the presented FEs, according to CUF. A few problems are analyzed to show the effectiveness of the proposed approach. Various laminations, thickness ratios and curvature ratios are considered. The results, obtained with different theories contained in the CUF, are compared with both the elasticity solutions given in literature and the analytical solutions obtained using the CUF and the Navier's method.

Mixed-dimensional coupling modeling for laser forming process

2014 ◽  
Vol 228 (16) ◽  
pp. 2950-2959
Author(s):  
Hong Shen ◽  
Jun Hu ◽  
Zhenqiang Yao
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Shell Element ◽  
Element Model ◽  
Thermomechanical Analysis ◽  
Coupling Method ◽  
Computational Time ◽  
Laser Forming ◽  
Forming Process ◽  
Shell Elements

Efficient laser forming modeling for industrial application is still in the developing stage and many researchers are in the process of modifying it. Conventional three-dimensional finite element models are still expensive on computational time. In this paper, a finite element model adopting a shell-solid coupling technique is developed for the thermomechanical analysis of laser forming process. In the shell-solid coupling method, an additional shell element plane is utilized to transfer heat flux and displacement from the solid elements to the shell elements. The effects of the additional interface shell element thickness on temperature distribution and final distortion are investigated. The presented shell-solid coupling method is evaluated by the results of three-dimensional simulations and experimental data.

PB-Spline Finite Element Shell Modeling and Refinement Technique

2009 ◽  
Author(s):  
Antonio Carminelli ◽  
Giuseppe Catania
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Spline Functions ◽  
B Spline ◽  
Numerical Examples ◽  
Complex Shapes ◽  
Spline Finite Element ◽  
Shell Finite Element ◽  
Element Technique

This paper presents a Point Based (PB) spline degenerate shell finite element model to analyze the behavior of thin and moderately thick-walled structures. Complex shapes are modeled with several B-spline patches assembled as in conventional finite element technique. The refinement of the solution is carried out by superimposing a tensorial set of B-spline functions on a patch and employing the PB-spline generalization. The domains for the numerical integration are defined by making use of the retained tensorial framework. Some numerical examples are presented. Considerations regarding strengths and limits of the approach then follow.

Subregion Analysis by the SBSF Method in Commercial Finite Element Software

1993 ◽  
Author(s):  
Charles E. Knight
Keyword(s):  
Finite Element ◽  
Complex Structure ◽  
Laminated Composite ◽  
Shell Element ◽  
Element Model ◽  
Interlaminar Stresses ◽  
Layered Shell ◽  
Shell Elements ◽  
Finite Element Software ◽  
Commercial Code

Abstract It is difficult to analyze a large, complex structure in sufficient detail to obtain accurate results everywhere. One approach to this problem is simply to refine the whole structure model in the regions of interest which is obviously costly. Another approach is to identify a subregion of the structure and develop a separate refined model of the subregion. The most recent method for subregion analysis presented in the literature[1] is called the Specified Boundary Stiffness and Force (SBSF) method. While the method is relatively straight forward and efficient, none of the commercial code vendors has yet included an implementation. This paper gives a brief review of the theory behind the method and then describes its application in two commercial finite element programs. Examples of the application of this method to the problem of a plate with a center hole in tensile loading are presented using ANSYS® and CAEDS(IDEAS)®. The results compare favorably to the theoretical value and show significant improvement in accuracy over the specified boundary displacement method implemented in ANSYS. The capability of the method is also demonstrated by transfer from a 2-D global model to a 3-D subregion model in a laminated composite plate. A laminated plate with a center hole is analyzed overall by use of a layered shell element model. A subregion around the hole is then analyzed using 3-D solid elements with nodal coupling to the layered shell elements on the subregion interface. The 3-D element model provides the well-known interlaminar stresses existing at the composite edge along the hole that are not available from the shell model.

scholarly journals TO THE QUESTION OF THE DETERMINATION OF GEOMETRIC CHARACTERISTICS OF THE SECTION OF CORRUGATED BEAMS WITH TRAPEZOIDAL WEBS BASED ON THE SIMULATION RESULTS

2019 ◽  
Vol 15 (1) ◽  
pp. 29-40
Author(s):  
Tatiana Dmitrieva ◽  
Khukhuudei Ulambaya
Keyword(s):  
Finite Element ◽  
Software Package ◽  
Element Model ◽  
Shell Elements ◽  
Geometric Characteristics ◽  
Corrugated Webs ◽  
Trapezoidal Profile ◽  
Shell Finite Element ◽  
Made In

An algorithm for calculating the geometric characteristics of steel I-beams with plate corrugated webs of arbitrary type is proposed. The algorithm is implemented using the I-beam with plate trapezoid webs as an example. The determination of reduced area and moments of inertia in the axes of the cross section of the trapezoidal profile based on the finite element modeling of the beam with shell elements in calculations for bending and axial compression in the “ANSYS 14.5” software package is described. The verification procedure has been performed for a shell finite element model using the example of an I-beam with a standard flat web. A table has been compiled of geometric characteristics of rod corrugated elements of a trapezoidal profile in order to realize their finite element calculation using a rod diagram. An example of the calculation of a flat frame with a horizontal corrugated element, made in software package “LIRA-SAPR” using a flat rod diagram is given.

Finite element bending analysis of symmetric and non-symmetric functionally graded sandwich beams using a novel parabolic shear deformation theory

2021 ◽  
pp. 146442072110050
Author(s):  
Mohamed-Ouejdi Belarbi ◽  
Abdelhak Khechai ◽  
Aicha Bessaim ◽  
Mohammed-Sid-Ahmed Houari ◽  
Aman Garg ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Shear Deformation ◽  
Transverse Shear ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Element Model ◽  
Beam Element ◽  
Functionally Graded ◽  
Sandwich Beams

In this paper, the bending behavior of functionally graded single-layered, symmetric and non-symmetric sandwich beams is investigated according to a new higher order shear deformation theory. Based on this theory, a novel parabolic shear deformation function is developed and applied to investigate the bending response of sandwich beams with homogeneous hardcore and softcore. The present theory provides an accurate parabolic distribution of transverse shear stress across the thickness and satisfies the zero traction boundary conditions on the top and bottom surfaces of the functionally graded sandwich beam without using any shear correction factors. The governing equations derived herein are solved by employing the finite element method using a two-node beam element, developed for this purpose. The material properties of functionally graded sandwich beams are graded through the thickness according to the power-law distribution. The predictive capability of the proposed finite element model is demonstrated through illustrative examples. Four types of beam support, i.e. simply-simply, clamped-free, clamped–clamped, and clamped-simply, are used to study how the beam deflection and both axial and transverse shear stresses are affected by the variation of volume fraction index and beam length-to-height ratio. Results of the numerical analysis have been reported and compared with those available in the open literature to evaluate the accuracy and robustness of the proposed finite element model. The comparisons with other higher order shear deformation theories verify that the proposed beam element is accurate, presents fast rate of convergence to the reference results and it is also valid for both thin and thick functionally graded sandwich beams. Further, some new results are reported in the current study, which will serve as a benchmark for future research.

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