Methodology for Quantitative Error-Assessment of Finite-Element Models

Author(s):  
John N. Majerus

Abstract Although recent developments in adaptivity and rezoning have enhanced the ease and use of the finite element method, the question remains: how good are the resulting simulations? In the case of highly nonlinear behavior, it appears that this question can only be answered by properly designed experiments. One such experiment involves the nonlinear behavior (material, geometry and boundary conditions) associated with a precision closed-die (PCD) forging. This paper presents some PCD data that could not be modeled by one particular FE code-simulation. Hopefully, these data can be used for the quantitative error-assessment of other codes for similar nonlinear simulations. Some possible code-simulation improvements are discussed and recommendations for future experiments are made.

2017 ◽  
Vol 54 (1) ◽  
pp. 180-179 ◽  
Author(s):  
Raul Cormos ◽  
Horia Petrescu ◽  
Anton Hadar ◽  
Gorge Mihail Adir ◽  
Horia Gheorghiu

The main purpose of this paper is the study the behavior of four multilayered composite material configurations subjected to different levels of low velocity impacts, in the linear elastc domain of the materials, using experimental testing and finite element simulation. The experimental results obtained after testing, are used to validate the finite element models of the four composite multilayered honeycomb structures, which makes possible the study, using only the finite element method, of these composite materials for a give application.


The finite element method has become established as a powerful tool for the solution of many problems of continuum mechanics where its physical interpretation, by analogy with discrete problems of structural analysis permits the user to exercise a considerable degree of insight and judgement in its use. Further it is now a recognized mathematical procedure of approximation which embraces many older methodologies (such as the finite difference method) as a subclass. In the field of geological studies its impact is fairly recent and only a limited application has been made to date. The techniques used here have been limited to those established over a decade ago in the parallel fields and recent developments and possibilities barely touched upon. In this paper the author therefore attempts to ( a ) outline some of the general mathematical and practical aspects of the method with illustrations from various fields which are relevant to geological problems, ( b ) survey accomplishments already made in geology and geotechnical fields, and ( c ) suggest some possible new extensions of application.


Author(s):  
O. L. TIUTKIN ◽  
D. O. BANNIKOV ◽  
V. А. MIROSHNYK ◽  
I. V. HELETIUK

Purpose. The development of construction of underground excavations of the Dnipro Metro requires analysis and scientific substantiation of design solutions based on technologies that are new for Ukraine. The aim of the scientific article is to analyze the combined design of the shaft of the Dnipro Metro by the finite element method with determination of force factors in the linings of the pile system and shotcrete system with further substantiation based on the results of design solutions to the real situation of Dnipro Metro construction. Methodology. Two finite element models were constructed for the analysis of the shaft № 1 of the Dnipro Metro by the finite element method. They reflect the combined design of the shaft, which consists of two parts. The finite-element model of the pile system, which reflects the shell of bored piles, supported by a cap beam and ring beams, is analyzed separately. The model for the shotcrete system, which is used for the second part of the shaft, which lies in a solid rock mass, is separately modeled and analyzed. Finite-element models of both systems are assigned real deformation and geometric parameters, as well as the load, which became the key to adequate calculations by the finite element method. Findings. During the numerical analysis of the combined structure of the shaft № 1 of Dnipro Metro, the force factors (normal forces and bending moments) for the pile system and the shotcrete system were determined. These results became the basis for the reinforcement of both systems. Originality. A numerical analysis of the shaft structure was performed, which provided a complete picture of the force factors that allow predicting the appearance of normal forces and bending moments in similar engineering and geological conditions. Practical value. The results of the analysis of the combined design of the shaft of the Dnipro Metro by the finite element method allowed to scientifically substantiate the design solutions and ensure high performance of both shaft systems № 1.


1989 ◽  
Vol 111 (4) ◽  
pp. 255-260 ◽  
Author(s):  
J. H. Lau ◽  
L. B. Lian-Mueller

The thermal stresses in microwave packages are studied by the finite element method. Emphasis is placed on the effects of material construction and design on the reliability of very small hermetic packages. Three different microwave packages have been designed and six finite element models (two for each design) have been analyzed. To verify the validity of the finite element results, some leak tests have been performed and the results agree with the analytical conclusions. The results presented herein should provide a better understanding of the thermal behavior of hermetic packages and should be useful for their optimal design.


1972 ◽  
Vol 14 (4) ◽  
pp. 229-237 ◽  
Author(s):  
C. Taylor ◽  
J. F. O'Callaghan

This paper comprises a report on recent developments in the application of the finite element method in the analysis of elastohydrodynamic lubrication (e.h.l.) problems. The basic formulation is effected, using the Galerkin approach and the domain under investigation is discretized using isoparametric elements. The techniques used to locate the inlet and outlet boundaries and those employed during successive iterations are illustrated by application to particular examples.


1994 ◽  
Vol 116 (4) ◽  
pp. 710-719 ◽  
Author(s):  
Foam-Zone Hsiao ◽  
An-Chen Lee

The load capacity of EMBs with a restricted air gap is usually small in comparison with that of traditional ball bearings. One possible way to overcome this limitation is to increase the operation field strength of EMBs; however, this approach unavoidably involves nonlinear characteristics of EMBs. This paper investigates the nonlinear behavior of two commonly used types of EMBs by using the finite element method, in which the nonlinear relation of the B-H curve, the flux leakage, and the fringing effect are taken into account. The behavior of the EMBs under different bias currents and gap lengths is investigated, as are the effects of geometric parameters on the bearing characteristics. The results of the paper provide a useful guide for designing EMBs when using their nonlinear characteristics.


1983 ◽  
Vol 105 (2) ◽  
pp. 138-144
Author(s):  
G. C. Feng ◽  
P. W. Schumacher

The finite element method was used to analyze the stresses in a rock bit cutter tooth under applied loads. Detailed finite element models were constructed to allow accurate descriptions of the structural material properties of a tooth design which includes carburization and hardmetal application. Numerical solutions were obtained for investigating stress concentrations and plastic region growths in a cutter tooth when loaded beyond its yield point. It was found that the finite element method can be a powerful tool for improving the performance of a cutter tooth. Design objectives can be achieved through parameteric studies of stress level variations against geometry and material property changes on a computer system.


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