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.

Some new results and current challenges in the finite element analysis of shells

Acta Numerica ◽  
2001 ◽  
Vol 10 ◽  
pp. 215-250 ◽  
Author(s):  
Dominique Chapelle
Keyword(s):  
Finite Element ◽  
Shell Theory ◽  
Shell Structures ◽  
Engineering Practice ◽  
Element Analysis ◽  
Shell Elements ◽  
Shell Models ◽  
The Finite Element Analysis ◽  
Shell Finite Element ◽  
Mathematical Analyses

This article, a companion to the article by Philippe G. Ciarlet on the mathematical modelling of shells also in this issue of Acta Numerica, focuses on numerical issues raised by the analysis of shells.Finite element procedures are widely used in engineering practice to analyse the behaviour of shell structures. However, the concept of ‘shell finite element’ is still somewhat fuzzy, as it may correspond to very different ideas and techniques in various actual implementations. In particular, a significant distinction can be made between shell elements that are obtained via the discretization of shell models, and shell elements – such as the general shell elements – derived from 3D formulations using some kinematic assumptions, without the use of any shell theory. Our first objective in this paper is to give a unified perspective of these two families of shell elements. This is expected to be very useful as it paves the way for further thorough mathematical analyses of shell elements. A particularly important motivation for this is the understanding and treatment of the deficiencies associated with the analysis of thin shells (among which is the locking phenomenon). We then survey these deficiencies, in the framework of the asymptotic behaviour of shell models. We conclude the article by giving some detailed guidelines to numerically assess the performance of shell finite elements when faced with these pathological phenomena, which is essential for the design of improved procedures.

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.

The Modal Analysis and Modeling Study of the Spacecraft Payload Load-Bearing Floor Structure

2012 ◽  
Vol 226-228 ◽  
pp. 271-274
Author(s):  
Sheng Yang ◽  
Chen Chao Ma ◽  
Guo Feng Li ◽  
Rui Jie Wang
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Structural Design ◽  
Optimized Design ◽  
Element Analysis ◽  
Load Bearing ◽  
Shell Elements ◽  
Analysis Process ◽  
Space Industry ◽  
Bearing Structure

As space industry and technology develop, the spacecraft structure systems become increasingly complex and the scales become much larger. Early in the project stage, finite element analysis is required to rapidly and accurately analyze and forecast dynamic characteristics of spacecraft. Based on this, the optimized structural design of spacecraft is then determined. Theoretical analysis done, the effect of both the type and size of shell elements and solid elements on calculation result is discussed during the dynamic analysis process. Shell elements and solid elements are respectively used for the study on load-bearing structure of spacecraft payload instrument. The purpose is, based on meeting the requirement of accuracy, to quickly conduct finite element dynamic analysis of the structure in the early payload structural design and provide a reference for the optimized design of spacecraft structure.

Multiobjective optimization of process variables in single-point incremental forming using grey relational analysis coupled with entropy weights

2021 ◽  
pp. 146442072110204
Author(s):  
Abdulmajeed Dabwan ◽  
Adham E Ragab ◽  
Mohamed A Saleh ◽  
Atef M Ghaleb ◽  
Mohamed Z Ramadan ◽  
...  
Keyword(s):  
Grey Relational Analysis ◽  
Incremental Forming ◽  
Single Point ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Numerical Control ◽  
Single Point Incremental Forming ◽  
Process Variables ◽  
Relational Analysis ◽  
Grey Relational

Incremental sheet forming is a specific group of sheet forming methods that enable the manufacture of complex parts utilizing computer numerical control instead of specialized tools. It is an incredibly adaptable operation that involves minimal usage of sophisticated tools, dies, and forming presses. Besides its main application in the field of rapid prototyping, incremental sheet forming processes can be used for the manufacture of unique parts in small batches. The goal of this study is to broaden the knowledge of the deformation process in single-point incremental forming. This work studies the deformation behavior in single-point incremental forming by experimentally investigating the principal stresses, principal strains, and thinning of single-point incremental forming products. Conical-shaped components are fabricated using AA1050-H14 aluminum alloy at various combinations of fundamental variables. The factorial design is employed to plan the experimental study and analysis of variance is conducted to analyze the results. The grey relational analysis approach coupled with entropy weights is also implemented to identify optimum process variables for single-point incremental forming. The results show that the tool diameter has the greatest effect on the thinning of the SPIF product, followed by the sheet thickness, step size, and feed rate.

Buckling characteristics of cut-out borne composite stiffened hyperbolic paraboloid shell panel

2021 ◽  
pp. 146442072110058
Author(s):  
Sarmila Sahoo
Keyword(s):  
Finite Element ◽  
Orientation Angle ◽  
Buckling Load ◽  
Benchmark Problems ◽  
Hyperbolic Paraboloid ◽  
Element Analysis ◽  
Load Effect ◽  
Global Buckling ◽  
Fiber Orientation Angle ◽  
Shell Panel

The present study investigates buckling characteristics of cut-out borne stiffened hyperbolic paraboloid shell panel made of laminated composites using finite element analysis to evaluate the governing differential equations of global buckling of the structure. The finite element code is validated by solving benchmark problems from literature. Different parametric variations are studied to find the optimum panel buckling load. Laminations, boundary conditions, depth of stiffener and arrangement of stiffeners are found to influence the panel buckling load. Effect of different parameters like cut-out size, shell width to thickness ratio, degree of orthotropy and fiber orientation angle of the composite layers on buckling load are also studied. Parametric and comparative studies are conducted to analyze the buckling strength of composite hyperbolic paraboloid shell panel with cut-out.

scholarly journals Use of Dynamic Analysis to Investigate the Behaviour of Short Neutral Sections in the Overhead Line Electrification

2021 ◽  
Vol 6 (5) ◽  
pp. 62
Author(s):  
John Morris ◽  
Mark Robinson ◽  
Roberto Palacin
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Model Simulation ◽  
Analysis Tool ◽  
Overhead Line ◽  
Element Analysis ◽  
Novel Approach ◽  
Section Model ◽  
The Uk ◽  
Neutral Section

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters.

NOVEL COUPLING CONSTRAINT TECHNIQUE FOR EXPLICIT FINITE ELEMENT ANALYSIS

2004 ◽  
Vol 01 (02) ◽  
pp. 309-328
Author(s):  
R. J. HO ◽  
S. A. MEGUID ◽  
R. G. SAUVÉ
Keyword(s):  
Finite Element ◽  
Current Method ◽  
Explicit Integration ◽  
Rotation Tensor ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Wide Range ◽  
Large Rotations ◽  
Generalized Constraint

This paper presents a unified novel technique for enforcing nonlinear beam-to-shell, beam-to-solid, and shell-to-solid constraints in explicit finite element formulations. The limitations of classical multi-point constraint approaches are examined at length, particularly in the context of explicit solution schemes. Novel formulation of a generalized constraint method that ensures proper element coupling is then presented, and its computer implementation in explicit integration algorithms is discussed. Crucial in this regard is the accurate and efficient representation of finite rotations, accomplished using an incremental rotation tensor. The results of some illustrative test cases show the accuracy and robustness of the newly developed algorithm for a wide range of deformation, including that in which large rotations are encountered. When compared to existing works, the salient features of the current method are in evidence.

Finite Element Analysis of Incremental Sheet Forming for Metal Sheet

2018 ◽  
Vol 783 ◽  
pp. 148-153
Author(s):  
Muhammad Sajjad ◽  
Jithin Ambarayil Joy ◽  
Dong Won Jung
Keyword(s):  
Mechanical Properties ◽  
Sheet Metal ◽  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Machining Process ◽  
Machining Parameters ◽  
Forming Process ◽  
Element Analysis ◽  
Tool Diameter

Incremental sheet metal forming, is a non-conventional machining process which offers higher formability, flexibility and low cost of production than the traditional conventional forming process. Punch or tool used in this forming process consecutively forces the sheet to deform locally and ultimately gives the target profile. Various machining parameters, such as type of tool, tool path, tool size, feed rate and mechanical properties of sheet metal, like strength co-efficient, strain hardening index and ultimate tensile strength, effects the forming process and the formability of final product. In this research paper, Single Point Incremental Forming was simulated using Dassault system’s Abaqus 6.12-1 and results are obtained. Results of sheet profile and there change in thickness is investigated. For this paper, we simulated the process in abaqus. The tool diameter and rotational speed is find out for the production of parts through incremental forming. The simulation is done for two type of material with different mechanical properties. Various research papers were used to understand the process of incremental forming and its simulation.

Sign in / Sign up

Export Citation Format

Share Document