A Curved C0 Shell Element Based on Assumed Natural-Coordinate Strains

1986 ◽  
Vol 53 (2) ◽  
pp. 278-290 ◽  
Author(s):  
K. C. Park ◽  
G. M. Stanley
Keyword(s):  
Shell Element ◽  
Benchmark Problems ◽  
Integration Rule ◽  
Shell Elements ◽  
Curvature Effects ◽  
Point Integration ◽  
Membrane Bending ◽  
Transverse Shear Locking ◽  
Natural Coordinate ◽  
Membrane Strain

A curved C0 shell element is presented, which corrects several deficiencies in existing quadratic shell elements. The improvements realized in the present element include rank sufficiency without transverse shear locking, consistent membrane strain interpolation that admits inextensional bending without reduced integration, and adequate representation of curvature effects to capture the important membrane-bending coupling. The element can be constructed either by a nine-point integration rule or by a four-point integration rule with the proper rank compensating terms. Numerical experiments with the present element on several benchmark problems indicate that the element yields accurate and reliable solutions without any ostensible deficiency. The element is recommended for production analysis of shell structures.

Element-Independent Pure Deformational and Co-Rotational Methods for Triangular Shell Elements in Geometrically Nonlinear Analysis

2018 ◽  
Vol 18 (05) ◽  
pp. 1850065 ◽  
Author(s):  
Y. Q. Tang ◽  
Y. P. Liu ◽  
S. L. Chan
Keyword(s):  
Nonlinear Analysis ◽  
Nonlinear Problems ◽  
Shell Element ◽  
Benchmark Problems ◽  
Element Formulation ◽  
Geometrically Nonlinear ◽  
Plate Element ◽  
Membrane Element ◽  
Geometrically Nonlinear Analysis ◽  
Shell Elements

Proposed herein is a novel pure deformational method for triangular shell elements that can decrease the element quantities and simplify the element formulation. This approach has computational advantages over the conventional finite element method for linear and nonlinear problems. In the element level, this method saves time for computing stresses, internal forces and stiffness matrices. A flat shell element is formed by a membrane element and a plate element, so that the pure deformational membrane and plate elements are derived and discussed separately in this paper. Also, it is very convenient to incorporate the proposed pure deformational method into the element-independent co-rotational (EICR) framework for geometrically nonlinear analysis. Thus, on the basis of the pure deformational method, a novel EICR formulation is proposed which is simpler and has more clear physical characteristics than the traditional formulation. In addition, a triangular membrane element with drilling rotations and the discrete Kirchhoff triangular plate element are used to verify the proposed pure deformational method, although several benchmark problems are employed to verify the robustness and accuracy of the proposed EICR formulations.

Resolution of Defects in Degenerated Shell Elements Through Modification of Gauss Integration

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1877-1883 ◽  
Author(s):  
Y. D. Kwon ◽  
N. S. Goo ◽  
B. S. Lim
Keyword(s):  
Integration Method ◽  
Time Integration ◽  
Shell Element ◽  
Zero Energy ◽  
Integration Rule ◽  
Shell Elements ◽  
Reduced Integration ◽  
Stiffness Matrices ◽  
Assumed Strain ◽  
Degenerated Shell Element

In this paper, the modified Gauss integration method is developed to eliminate the shear and membrane locking phenomena of the degenerated shell element. The behavior of the element based on the Mindlin/Reissner theory in plates and shells sometimes causes a problem. In displacement-based shell elements, the full integration of stiffness matrices leads to a 'locking' or over-stiff behavior. The selective or reduced integration procedures may often overcome these difficulties, while overstiff solutions may still occur in the analysis with a highly constrained boundary. Except for the six zero-energy modes associated with shell rigid body movements, during the reduced integration of the stiffness matrices, many extra zero spurious energy modes are introduced due to reduced integration. This is a serious defect of degenerated shell element. In previous studies, several methods such as the addition of nonconforming displacement modes, an assumed strain method, and hybrid and mixed elements have been introduced in an attempt to overcome these difficulties. In this study a newly modified Gauss integration method combining both a selective and a weight-modified integration is suggested. Numerical experiments show that the new selective integration and weight-modified integration rule is very effective in eliminating the shear and membrane locking in static and modal analyses, and removes spurious zero-energy modes as well. Also, the effectiveness of proposed shell element is tested by applying it to some example problems. We solved post-buckling problem by the Riks arc-length method and dynamic problem by the Newmark's time integration method, as well as static problems.

A Parametric Study for Four Node Bilinear EAS Shell Elements

2010 ◽  
Vol 26 (4) ◽  
pp. 431-438
Author(s):  
Cengiz Polat
Keyword(s):  
Variational Principle ◽  
Transverse Shear ◽  
Strain Field ◽  
Shell Element ◽  
Shell Structures ◽  
Shear Locking ◽  
Shell Elements ◽  
Assumed Strain ◽  
Dependent Strain ◽  
Transverse Shear Locking

ABSTRACTA locking free formulation of 4-node bilinear shell element and its application to shell structures is demonstrated. The Enhanced Assumed Strain (EAS) method based on three-field variational principle of Hu-Washizu is used in the formulation. Transverse shear locking and membrane locking are circumvented by means of enhancing the displacement-dependent strain field with extra assumed strain field. Several benchmark shell problems are analyzed.

scholarly journals Dynamic Analysis of Shell Structures with Application to Blast Resistant Doors

2003 ◽  
Vol 10 (4) ◽  
pp. 269-279 ◽  
Author(s):  
C.G. Koh ◽  
K.K. Ang ◽  
P.F. Chan
Keyword(s):  
Dynamic Analysis ◽  
Single Point ◽  
Numerical Control ◽  
Shell Structures ◽  
Benchmark Problems ◽  
Explicit Integration ◽  
Element Analysis ◽  
Application Study ◽  
Integration Rule ◽  
Shell Elements

This paper concerns the dynamic analysis of shell structures, with emphasis on application to steel and steel-concrete composite blast resistant doors. In view of the short duration and impulsive nature of the blast loading, an explicit integration method is adopted. This approach avoids time-consuming computations of structural stiffness matrix and solving of simultaneous nonlinear equations. Single-point quadrature shell elements are used, with numerical control to suppress spurious hourglass modes. Composite shells are handled by an appropriate integration rule across the thickness. Both material and geometric nonlinearities are accounted for in the formulation. Contact and gap problems are considered using bilinear spring elements in the finite element analysis. Numerical examples are presented for some benchmark problems and application study to blast resistant doors. Good correlation is generally obtained between the numerical results based on the software developed and the results obtained by other means including field blast tests.

A Finite Element for the Analysis of Shell Intersections

1996 ◽  
Vol 118 (4) ◽  
pp. 399-406 ◽  
Author(s):  
W. J. Koves ◽  
S. Nair
Keyword(s):  
Finite Element ◽  
Stress State ◽  
Three Dimensional ◽  
Shell Element ◽  
Theory Of Elasticity ◽  
Shell Elements ◽  
Asme Code ◽  
Form Theory ◽  
Computation Scheme ◽  
Shell Intersections

A specialized shell-intersection finite element, which is compatible with adjoining shell elements, has been developed and has the capability of physically representing the complex three-dimensional geometry and stress state at shell intersections (Koves, 1993). The element geometry is a contoured shape that matches a wide variety of practical nozzle configurations used in ASME Code pressure vessel construction, and allows computational rigor. A closed-form theory of elasticity solution was used to compute the stress state and strain energy in the element. The concept of an energy-equivalent nodal displacement and force vector set was then developed to allow complete compatibility with adjoining shell elements and retain the analytical rigor within the element. This methodology provides a powerful and robust computation scheme that maintains the computational efficiency of shell element solutions. The shell-intersection element was then applied to the cylinder-sphere and cylinder-cylinder intersection problems.

scholarly journals Modelling of confined masonry structure and its application for the design of multi-story building

2019 ◽  
Vol 276 ◽  
pp. 01034
Author(s):  
Made Sukrawa ◽  
Gede Pringgana ◽  
Putu Ayu Ratih Yustinaputri
Keyword(s):  
Maximum Stress ◽  
Residential Building ◽  
Shell Element ◽  
Reinforced Concrete Beams ◽  
Seismic Load ◽  
Confined Masonry ◽  
Shell Elements ◽  
Wall Strength ◽  
Story Building ◽  
Better Than

The confined masonry (CM) structure has been commonly used in the construction of one-story buildings in Indonesia. Its application for multi-story buildings however, is not yet as popular as the alternative options. This research numerically investigated the behavior of confined masonry and its application for use as the main structure of multi-story buildings subjected to seismic loading. From the validation models it was revealed that, using shell element for masonry walls, reinforced concrete beams and tie-columns, the CM model mimic the load deformation curve of tested specimen better than that using frame and shell elements. The application of the modeling technique for the design of 3-story residential building using wall density index less than that suggested in the literature resulted in a safe and stiff structure. The wall stresses under design seismic load were still less than the wall strength and the drift ratio of the model was 0.06% much smaller than the limit of 0.2%. The maximum stress observed at the corners of wall opening justify the need for confinement along the opening.

scholarly journals RESPON SEISMIK STRUKTUR RANGKA DINDING PENGISI YANG DIMODEL DENGAN ELEMEN SHELL PENUH DAN PARSIAL

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Putu Ratna Suryantini ◽  
M. Sukrawa ◽  
I. A. M Budiwati
Keyword(s):  
Shell Model ◽  
3D Structure ◽  
Shell Element ◽  
Maximum Load ◽  
3D Models ◽  
Frame Structure ◽  
Natural Period ◽  
Shell Elements ◽  
Frame Model ◽  
Wall Strength

Abstract: Research on the seismic response of in-filled frame structure has been done with in-filled frame model as full and partial shell elements. The wall is considered active until the maximum load on the full shell models, while the partial shell model using the gradual load with the strength of the wall is considered inactive if the stress of the wall exceeded the wall strength The 4 storey hotel building with full wall in x-direction and wall with opening in y-direction were modeled in SAP 2000 as 3D infilled-frame using full and partial shell element. In Mxy models, both wall were included in the model, while in My models, only the wall in y-direction included. Therefore, 4 models were obtained, there are full shell model MxyShPn and MyShPn and partial shell model MyShPar and MyShPar. In addition, 2 diagonal strut models MxyS and MyS  and an open frame model MOF were made as comparison. Prior to model 3D structure, validation models were created using test result condited by other as reference. For that purphose 5 2D models were created there are open frame model MOF, single strut model MST, multiple strut model MSG, full shell model MShPn and  partial shell model MShPar. From validation models, it is apparent that the MxyShPar model mimic the behavior of tested structure better than the other models. From the 3D models analysis result show that the displacement in x-direction of MxyShPn, MxyShPar, MxyS were 89%, 85%, 84% smaller than those of MOF, respectively inclusion of wall in the models, also reduce the internal forces and reduse the natural period of the sctructure.

Simulating welding with shell elements

2004 ◽  
Vol 120 ◽  
pp. 347-354
Author(s):  
F. Faure ◽  
J.-M. Bergheau ◽  
J.-B. Leblond
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Shell Element ◽  
Thermal Calculation ◽  
Transformation Plasticity ◽  
Thin Structures ◽  
Shell Elements ◽  
Mechanical Calculation ◽  
Complex Interactions ◽  
Mechanical Phenomena

Finite element simulations can be used to evaluate residual stresses and distortions induced by welding. Such simulations must account for complex interactions between thermal, metallurgical and mechanical phenomena. “Local” simulations are often sufficient for satisfactory predictions of residual stresses in the heat-affected zone (HAZ), but 3D “global” simulations are often necessary to calculate distortions, which can be important even far from the HAZ. In order to avoid such heavy calculations, a special shell element is proposed for the simulation of welding of thin structures. The thermal calculation involves only one nodal degree of freedom but fully accounts for boundary conditions on the faces of the shell. The metallurgical and mechanical calculations are based on a “multi-layer” approach. Due account is taken of transformation plasticity in the mechanical calculation. Numerical results obtained with this approach are compared to those of experiments and some 3D simulation.

Locking Behavior of Isoparametric Curved Beam Finite Elements

1995 ◽  
Vol 48 (11S) ◽  
pp. S25-S29 ◽  
Author(s):  
Miguel Luiz Bucalem ◽  
Klaus-Ju¨rgen Bathe
Keyword(s):  
Shell Element ◽  
Beam Element ◽  
Curved Beam ◽  
Shear Locking ◽  
Shell Elements ◽  
One Dimensional ◽  
Curved Beam Element ◽  
The One ◽  
Insight Into ◽  
The Continuum

We present a study of the membrane and shear locking behavior in an isoparametric curved beam element. The objective is to gain insight into the locking phenomenon, specially membrane locking, of continuum based degenerated shell elements. This is possible since the isobeam element is the one-dimensional analogue of the continuum based shell element. In this context, reduced integration and mixed interpolation schemes are briefly examined. Such a study can be a valuable aid when developing new shell elements.

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