Using Analytical/Numerical Matching With Finite Element Analysis to Solve a Fluid-Loaded Structural Dynamics Problem

2000 ◽  
Author(s):  
Christopher D. Park ◽  
Linda P. Franzoni
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Original Problem ◽  
Lower Boundary ◽  
Fluid Loading ◽  
Computationally Efficient ◽  
Principle Of Superposition ◽  
Element Analysis ◽  
Loading Effects ◽  
Rigid Supports

Abstract Two model problems are solved using a combination of Analytical/Numerical Matching (ANM) and Finite Element Analysis (FEA). The first problem is that of a thick, finite length beam driven by the motion of a small rigid support attached to its lower boundary. The second problem is a thick, infinitely long fluid-loaded beam driven by the motion of periodically spaced rigid supports (identical to the support of the first problem). The ANM process divides an original problem into local, matching, and global sub-problems through the use of a smooth force and the principle of superposition. In the two model problems presented, the same high-resolution local (in vacuo) problem is solved using FEA. The fluid loading effects can be accounted for entirely by the global problem. The problems presented show that ANM is a computationally efficient method that retains the high accuracy needed near structural discontinuities.

Separation of Primary Stress in Finite Element Analysis of Pressure Vessel with the Principle of Superposition

2007 ◽  
Vol 353-358 ◽  
pp. 373-376 ◽  
Author(s):  
Bing Jun Gao ◽  
Xiao Ping Shi ◽  
Hong Yan Liu ◽  
Jin Hong Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Engineering Application ◽  
Total Stress ◽  
Principle Of Superposition ◽  
Element Analysis ◽  
Primary Stress ◽  
The Finite Element Analysis ◽  
Asme Code ◽  
Allowable Load

A key problem in engineering application of “design by analysis” approach is how to decompose a total stress field obtained by the finite element analysis into different stress categories defined in the ASME Code III and VIII-2. In this paper, we suggested an approach to separate primary stress with the principle of superposition, in which the structure does not need to be cut into primary structure but analyzed as a whole only with decomposed load. Taking pressurized cylindrical vessel with plate head as example, the approach is demonstrated and discussed in detail. The allowable load determined by the supposed method is a little conservative than that determined by limited load analysis.

Applying Incompatible Meshes for Modeling Structural-Acoustic Domains in Energy Finite Element Analysis

2014 ◽  
Author(s):  
S. N. Medyanik ◽  
N. Vlahopoulos
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Differential Equations ◽  
Computationally Efficient ◽  
Exact Matching ◽  
Element Analysis ◽  
Energy Finite Element Analysis ◽  
Accuracy Of Results ◽  
New Formulation ◽  
Acoustic Interface

The Energy Finite Element Analysis (EFEA) has been developed for modeling coupled structural-acoustic systems at mid-to-high frequencies when conventional finite element methods are no longer computationally efficient because they require very fine meshes. In standard Finite Element Analysis (FEA) approach, governing differential equations are formulated in terms of displacements which vary harmonically with space. This requires larger numbers of elements at higher frequencies when wavelengths become smaller. In the EFEA, governing differential equations are formulated in terms of energy density that is spatially averaged over a wavelength and time averaged over a period. The resulting solutions vary exponentially with space which makes them smooth and allows for using much coarser meshes. However, current EFEA formulations require exact matching between the meshes at the boundaries between structural and acoustic domains. This creates practical inconveniences in applying the method as well as limits its use to only fully compatible meshes. In this paper, a new formulation is presented that allows for using incompatible meshes in EFEA modeling, when shapes and/or sizes of elements at structural-acoustic interfaces do not match. In the main EFEA procedure, joints formulations between structural and acoustic domains have been changed in order to deal with non-matching elements. In addition, the new Pre-EFEA procedure which allows for automatic searching and formation of the new types of joints is developed for models with incompatible meshes. The new method is tested using a spherical shaped structural-acoustic interface. Results for incompatible meshes are validated by comparing to solutions obtained using regular compatible meshes. The effects of mesh incompatibility on the accuracy of results are discussed.

sFEA: A Secure Finite Element Analysis Technique

2019 ◽  
Vol 19 (3) ◽  
Author(s):  
Siva C. Chaduvula ◽  
Mikhail J. Atallah ◽  
Jitesh H. Panchal
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Large Scale ◽  
Information Leakage ◽  
Computational Techniques ◽  
Computationally Efficient ◽  
Element Analysis ◽  
Computational Overhead ◽  
Analysis Technique ◽  
Material Information

Designers need a way to overcome information-related risks, including information leakage and misuse by their own collaborators during collaborative product realization. Existing cryptographic techniques aimed at overcoming these information-related risks are computationally expensive and impractical even for moderate problem sizes, and legal approaches such as nondisclosure agreements are not effective. The computational practicality problem is particularly pronounced for computational techniques, such as the finite element analysis (FEA). In this paper, we propose a technique that enables designers to perform simulations, such as FEA computations, without the need for revealing their information to anyone, including their design collaborators. We present a new approach, the secure finite element analysis approach, which enables designers to perform FEA without having to reveal structural/material information to their counterparts even though the computed answer depends on all the collaborators' confidential information. We build secure finite element analysis (sFEA) using computationally efficient protocols implementing a secure codesign (SCD) framework. One of our findings is that the direct implementation of using SCD framework (termed as naïve sFEA) suffers from lack of scalability. To overcome these limitations, we propose hybrid sFEA that implements performance improvement strategies. We document and discuss the experiments we conducted to determine the computational overhead imposed by both naïve and hybrid sFEA. The results indicate that the computational burden imposed by hybrid sFEA makes it challenging for large-scale FEA—our scheme significantly increases the problem sizes that can be handled when compared to implementations using previous algorithms and protocols, but large enough problem sizes will swamp our scheme as well (in some sense this is unavoidable because of the cubic nature of the FEA time complexity).

Finite Element Based Point Stress Criterion for Predicting the Notched Strengths of Composite Plates

2012 ◽  
Vol 28 (3) ◽  
pp. 401-406 ◽  
Author(s):  
K.-H. Tsai ◽  
C.-L. Hwan ◽  
M.-J. Lin ◽  
Y. S. Huang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Characteristic Length ◽  
Composite Plates ◽  
Element Model ◽  
Principle Of Superposition ◽  
Element Analysis ◽  
Stress Criterion ◽  
The Finite Element Analysis ◽  
Empirical Function

AbstractIn this study, a novel procedure has been developed for predicting the notched strengths of composite plates each with a center hole. In this approach, the stress distribution of a composite plate with a center hole is first obtained by a finite element analysis, in which the experimental notched strength is applied at the boundary of the finite element model. Secondly, the point stress criterion (PSC) is used to find the characteristic length for each plate with different size of hole by an interpolation of the finite element analysis results. The characteristic length is then expressed as an empirical function of the hole size as well as the width of the plate. Finally, the notched strengths of composite plates are predicted based on the empirical function and the finite element analysis results incorporated with the principle of superposition in elasticity. For validation, three different cases from the literatures are adopted for comparison. It is shown that the predicted notched strengths by this new methodology agree well with both the experimental results and the results from analytical solutions based PSC.

Deep Drawing of Square-Shaped Sheet Metal Parts, Part 1: Finite Element Analysis

1993 ◽  
Vol 115 (1) ◽  
pp. 102-109 ◽  
Author(s):  
S. A. Majlessi ◽  
D. Lee
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Membrane Properties ◽  
Computationally Efficient ◽  
Element Analysis ◽  
Sheet Metal Parts ◽  
Part Geometry ◽  
Analysis Technique ◽  
The Finite Element Analysis ◽  
Good Agreement

The process of square-cup drawing is modeled employing a simplified finite element analysis technique. In order to make the algorithm computationally efficient, the deformation (total strain) theory of plasticity is adopted. The solution scheme is comprised of specifying a mesh of two-dimensional finite elements with membrane properties over the deformed configuration of the final part geometry. The initial positions of these elements are then computed by minimization of the potential energy, and therefore the strain distributions are determined. In order to verify predictions made by the finite element analysis method, a drawing apparatus is built and various drawing experiments are carried out. A number of circular and square cups are drawn and strain distributions measured. It is observed that there is generally a good agreement between computed and measured results for both axisymmetric and nonaxisymmetric cases.

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