scholarly journals Two Scales, Hybrid Model for Soils, Involving Artificial Neural Network and Finite Element Procedure

2015 ◽  
Vol 36 (2) ◽  
pp. 29-36
Author(s):  
Marcin Krasiński ◽  
Marek Lefik
Keyword(s):  
Finite Element ◽  
Engineering Properties ◽  
Single Element ◽  
Laboratory Sample ◽  
Engineering Problems ◽  
Geotechnical Problem ◽  
Finite Element Procedure ◽  
Correct Representation ◽  
Constitutive Parameters ◽  
Level Analysis

Abstract A hybrid ANN-FE solution is presented as a result of two level analysis of soils: a level of a laboratory sample and a level of engineering geotechnical problem. Engineering properties of soils (sands) are represented directly in the form of ANN (this is in contrast with our former paper where ANN approximated constitutive relationships). Initially the ANN is trained with Duncan formula (Duncan and Chang [2]), then it is re-trained (calibrated) with some available experimental data, specific for the soil considered. The obtained approximation of the constitutive parameters is used directly in finite element method at the level of a single element at the scale of the laboratory sample to check the correct representation of the laboratory test. Then, the finite element that was successfully tested at the level of laboratory sample is used at the macro level to solve engineering problems involving the soil for which it was calibrated.

A Finite Element Procedure of a Cyclic Thermoviscoplasticity Model for Solder and Copper Interconnects

1998 ◽  
Vol 120 (1) ◽  
pp. 24-34 ◽  
Author(s):  
C. Fu ◽  
D. L. McDowell ◽  
I. C. Ume
Keyword(s):  
Finite Element ◽  
Electronic Packaging ◽  
Copper Interconnects ◽  
Implicit Time ◽  
Integration Scheme ◽  
Single Element ◽  
Ofhc Copper ◽  
Computation Efficiency ◽  
Backward Euler ◽  
Finite Element Procedure

A finite element procedure using a semi-implicit time-integration scheme has been developed for a cyclic thermoviscoplastic constitutive model for Pb-Sn solder and OFHC copper, two common metallic constituents in electronic packaging applications. The scheme has been implemented in the commercial finite element (FE) code ABAQUS (1995) via the user-defined material subroutine, UMAT. Several single-element simulations are conducted to compare with previous test results, which include monotonic tensile tests, creep tests, and a two-step ratchetting test for 62Sn36Pb2Ag solder; a nonproportional axial-torsional test and a thermomechanical fatigue (TMF) test for OFHC copper. At the constitutive level, we also provide an adaptive time stepping algorithm, which can be used to improve the overall computation efficiency and accuracy especially in large-scale FE analyses. We also compare the computational efforts of fully backward Euler and the proposed methods. The implementation of the FE procedure provides a guideline to apply user-defined material constitutive relations in FE analyses and to perform more sophisticated thermomechanical simulations. Such work can facilitate enhanced understanding thermomechanical reliability issue of solder and copper interconnects in electronic packaging applications.

Comparison of Analytical and FEM Solutions of the Contact Tasks of Foundation - Subsoil Interaction

2015 ◽  
Vol 769 ◽  
pp. 55-60
Author(s):  
Lubos Hrustinec ◽  
Jozef Sumec ◽  
Jozef Kuzma
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Normal Stresses ◽  
Tabular Form ◽  
Calculation Methods ◽  
Efficient Tool ◽  
Engineering Problems ◽  
Geotechnical Problem ◽  
Contact Tasks

In this paper we shall deal with application of analytical and numerical calculation methods in selected geotechnical problem. It is well-known that numerical modeling by Finite Element Method (FEM) is often used for solving complicated engineering problems. FEM is very universal and efficient tool for their solution. In our case a contact task of rigid shallow (circular, rectangular and strip) foundations loaded by centric force, has been solved. The obtained results of vertical normal stresses distributions according to analytical methods and FEM solutions have been analyzed and mutually compared. Results of the calculations have been presented in graphical and tabular form, too.

On the Analysis of Distortion and Residual Stress in Carburized Steels

1992 ◽  
Vol 114 (4) ◽  
pp. 362-367 ◽  
Author(s):  
M. Henriksen ◽  
D. B. Larson ◽  
C. J. Van Tyne
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Yield Surface ◽  
Experimental Sample ◽  
Carbon Profile ◽  
Plastic Yield ◽  
Property Data ◽  
Finite Element Procedure ◽  
Gear Steels ◽  
Constitutive Parameters

This paper appraises the accuracy with which distortion and residual stress can be predicted in carburized and quenched gear steels. An experimental sample is heattreated such that a nonsymmetric carbon profile results. During quenching, the strip develops longitudinal transformation strains that result in amplified transverse deflections, similar to those of thin bimetallic strips. Deformations in carburized SAE 4023 and SAE 4620 alloys are compared with finite element predictions. The finite element procedure is based on an elastic-plastic yield surface which includes dependence on temperature. The analysis uses property data published and used by others. Some, but not all, of the predicted distortions agree with experiments; the study shows that distortions are quite sensitive to small variations in constitutive parameters. The paper includes recommendations for practitioners using finite element procedures for prediction of residual stress.

THE ROLE OF FINITE ELEMENT METHOD IN CIVIL ENGINEERING

2018 ◽  
Vol 5 (02) ◽  
Author(s):  
Er. Hardik Dhull
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Approximate Solution ◽  
Analytical Method ◽  
Civil Engineering ◽  
The Finite Element Method ◽  
Engineering Problems ◽  
Building Components ◽  
Element Method

The finite element method is a numerical method that is used to find solution of mathematical and engineering problems. It basically deals with partial differential equations. It is very complex for civil engineers to study various structures by using analytical method,so they prefer finite element methods over the analytical methods. As it is an approximate solution, therefore several limitationsare associated in the applicationsin civil engineering due to misinterpretationof analyst. Hence, the main aim of the paper is to study the finite element method in details along with the benefits and limitations of using this method in analysis of building components like beams, frames, trusses, slabs etc.

Analysis of Deformation for PC Thin-Wall Box Girders Exposed to Fire

2011 ◽  
Vol 368-373 ◽  
pp. 930-933
Author(s):  
Wei Hou ◽  
Shuan Hai He ◽  
Cui Juan Wang ◽  
Gang Zhang
Keyword(s):  
Finite Element ◽  
Thin Wall ◽  
Fire Load ◽  
Box Girders ◽  
Conduction Model ◽  
Load Model ◽  
Deformation Problem ◽  
Finite Element Procedure ◽  
Thin Walled

Being aimed to deformation problem of pre-stressed concrete thin-walled multi-room box girders exposed to co-action of fire and load, on the basis of enthalpy conduction model and thermo-mechanics parameters, the finite element procedure was applied to analyze the deformation of three spans pre-stressed concrete thin-walled multi-room box girders exposed to co-action of fire and load. In conclusion, the deflection is obvious under action of the variation width and fire load model.

A Spectral Finite Element Model for Wave Propagation Analysis in Laminated Composite Plate

2006 ◽  
Vol 128 (4) ◽  
pp. 477-488 ◽  
Author(s):  
A. Chakraborty ◽  
S. Gopalakrishnan
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Shear Deformation ◽  
Mechanical Response ◽  
Laminated Composite ◽  
Wave Number ◽  
Single Element ◽  
Element Formulation ◽  
Frequency Wave ◽  
Spectral Finite Element

A new spectral plate element (SPE) is developed to analyze wave propagation in anisotropic laminated composite media. The element is based on the first-order laminated plate theory, which takes shear deformation into consideration. The element is formulated using the recently developed methodology of spectral finite element formulation based on the solution of a polynomial eigenvalue problem. By virtue of its frequency-wave number domain formulation, single element is sufficient to model large structures, where conventional finite element method will incur heavy cost of computation. The variation of the wave numbers with frequency is shown, which illustrates the inhomogeneous nature of the wave. The element is used to demonstrate the nature of the wave propagating in laminated composite due to mechanical impact and the effect of shear deformation on the mechanical response is demonstrated. The element is also upgraded to an active spectral plate clement for modeling open and closed loop vibration control of plate structures. Further, delamination is introduced in the SPE and scattered wave is captured for both broadband and modulated pulse loading.

Solving Mid-Frequency Acoustic Problem by the Meshless Method

2013 ◽  
Vol 444-445 ◽  
pp. 1471-1476
Author(s):  
Shuang Wang ◽  
Qi Bai Huang ◽  
Shan De Li
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Radial Basis Function ◽  
Efficient Method ◽  
Basis Function ◽  
Meshless Method ◽  
Medium Frequency ◽  
Pollution Effect ◽  
Acoustic Problem ◽  
Engineering Problems

It is well known that traditional finite element (FEM) is an efficient method in solving engineering problems. However, when solving the acoustic problems in medium frequency, FEM suffers from the so-called pollution effect, which is directly related to the dispersion. In this paper, meshless method based on radial basis function (RBF) is introduced to solve the acoustic problem, which shows that the dispersion can be greatly reduced, thus it is very suitable for the solution of mid-frequency acoustic problem. In addition, an algorithm is presented to treat the boundary condition, which improves the performance of the meshless method.

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