sFEA: A Lightweight, Scalable, and Secure Finite Element Analysis Technique

Author(s):  
Siva C. Chaduvula ◽  
Mikhail J. Atallah ◽  
Jitesh H. Panchal

Designers need a way to overcome information related risks, including information leakage and misuse from their own collaborators during a collaborative product realization process. Existing cryptographic techniques aimed at overcoming these information related risks are computationally expensive and slow even for moderate problem sizes, and legal approaches (e.g., the use of non-disclosure agreements) are not effective. The computational practicality problem is particularly pronounced for simulation computations like finite element analysis (FEA), that involve both a geometric partitioning (meshing) and computations of cubic time complexity. In this paper, we propose a technological approach that enables designers to perform simulations, such as FEA computations, without the need for revealing their information to anyone, including their design collaborators. We demonstrate our approach using secure finite element analysis (sFEA) 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 sFEA using computationally efficient protocols implementing a secure co-design framework. One of our findings is that the most natural implementations of sFEA, using existing protocols, suffer from limited scalability. To overcome these limitations, we propose strategies that help improve the scalability of sFEA. We document and discuss the experiments we conducted to determine the computational overhead imposed by sFEA. The results indicate that the computational burden imposed by 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). This work is another step towards opening up new avenues for improving the way information is exchanged in collaborative simulation computations such as FEA.

Author(s):  
Siva C. Chaduvula ◽  
Mikhail J. Atallah ◽  
Jitesh H. Panchal

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).


1993 ◽  
Vol 115 (1) ◽  
pp. 102-109 ◽  
Author(s):  
S. A. Majlessi ◽  
D. Lee

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.


1981 ◽  
Vol 18 (01) ◽  
pp. 51-68
Author(s):  
Donald Liu ◽  
Abram Bakker

Local structural problems in ships are generally the result of stress concentrations in structural details. The intent of this paper is to show that costly repairs and lay-up time of a vessel can often be prevented, if these problem areas are recognized and investigated in the design stages. Such investigations can be performed for minimal labor and computer costs by using finite-element analysis techniques. Practical procedures for analyzing structural details are presented, including discussions of the results and the analysis costs expended. It is shown that the application of the finite-element analysis technique can be economically employed in the investigation of structural details.


2013 ◽  
Vol 7 (1) ◽  
pp. 170-178 ◽  
Author(s):  
Weijun Yang ◽  
Yongda Yang ◽  
Jihua Yin ◽  
Yushuang Ni

In order to study the basic mechanical property of cast-in-place stiffening-ribbed-hollow-pipe reinforced concrete girderless floor, and similarities and differences of the structural performance compared with traditional floor, we carried out the destructive stage loading test on the short-term load test of floor model with four clamped edges supported in large scale, and conducted the long-term static load test. Also, the thesis conducted finite element analysis in virtue of ANSYS software for solid slab floor, stiffening-ribbed-hollow-pipe floor and tubular floor. The experiment indicates that the developing process of cracks, distribution and failure mode in stiffening-ribbed-hollow-pipe floor are similar to that of solid girderless floor, and that this kind of floor has higher bearing capacity and better plastic deformation capacity. The finite element analysis manifests that, compared with solid slab floor, the deadweight of stiffening-ribbed-hollow-pipe floor decreases on greater level while deformation increases little, and that compared with tubular floor, this floor has higher rigidity. So stiffening-ribbed-hollow-pipe reinforced concrete girderless floor is particularly suitable for long-span and large-bay building structure.


2000 ◽  
Author(s):  
Christopher D. Park ◽  
Linda P. Franzoni

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.


Author(s):  
S. N. Medyanik ◽  
N. Vlahopoulos

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.


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