Thermal Stress in Discretely Layered Structures with Functional Graded Materials

2008 ◽  
Vol 24 (4) ◽  
pp. 297-300 ◽  
Author(s):  
S.-F. Hwang ◽  
W.-T. Liao
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Three Dimensional ◽  
Stress Singularity ◽  
Layered Structures ◽  
Two Dimensional ◽  
Element Analysis ◽  
Graded Materials ◽  
Dimensional Finite Element ◽  
Graded Material

AbstractFunctional graded materials are generally provided in discretely layered structures to reduce the abrupt mismatch and to improve failure performance. To investigate the thermal stress singularity occurring at the intersection of an interface and a free end, two-dimensional and three-dimensional finite element analyses are performed for titanium and aluminum layers with or without functional graded materials. The results indicate that once the functional graded material is added, the stress singularity around the intersection of an interface and a free end could be significantly relieved. If more FGM layers are used, the stress singularity could be further reduced to a very small value. If the longitudinal normal stresses and interlaminar shear stress are considered, two-dimensional finite element analysis may be enough, while three-dimensional analysis is necessary for the interlaminar normal stress. Otherwise, one may underestimate its stress singularity.

THREE DIMENSIONAL FINITE ELEMENT SIMULATION OF THE FRETTING WEAR PROBLEMS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3890-3895 ◽  
Author(s):  
CHOON YEOL LEE ◽  
JOON WOO BAE ◽  
BYUNG SUN CHOI ◽  
YOUNG SUCK CHAI
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Fretting Wear ◽  
Symmetric Model ◽  
Two Dimensional ◽  
Element Analysis ◽  
Inconel 690 ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The structural integrity of steam generators in nuclear power plants is very much dependent upon the fretting wear characteristics of Inconel 690 U-tubes. In this study, a finite element analysis was used to investigate fretting wear on the secondary side of the steam generator, which arises from flow-induced vibrations (FIV) between the U-tubes and supports or foreign objects. Two-dimensional and three-dimensional finite element analyses were adopted to investigate the fretting wear problems. The purpose of the two-dimensional analysis, which simulated the contact between a punch and a plate, was to demonstrate the validity of using finite element analysis to analyze fretting wear problems. This was achieved by controlling the value of the wear constant and the number of cycles. The two-dimensional solutions obtained from this study were in good agreement with previous results reported by Strömberg. In the three-dimensional finite element analysis, a quarterly symmetric model was used to simulate tubes contacting at right angles. The results of the analyses showed donut-shaped wear along the contacting boundary, which is a typical feature of fretting wear.

Finite element analysis of peak stress and stress gradient at an elliptical through-hole

2017 ◽  
Vol 52 (5) ◽  
pp. 277-287
Author(s):  
Kristine Klungerbo ◽  
Gunnar Härkegård
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plane Strain ◽  
Stress Gradient ◽  
Three Dimensional ◽  
Peak Stress ◽  
Two Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Through Hole

The peak stress and stress gradient (parameters required for fatigue strength assessment) at an elliptical through-hole in a wide plate under uniaxial tension have been studied by means of three-dimensional finite element analysis with high mesh density. Dimensionless variables have been used throughout the investigation. The accuracy of two-dimensional finite element analysis has been assessed by extrapolating peak stress at an elliptical hole to infinite plate width and mesh density and comparing the extrapolated value with the closed-form Kolosov–Inglis solution (deviation < 0.2%). First- and second-order elements with full and reduced integration have been employed. Methods for determining stress gradients, using a varying number of nodal stresses, have been investigated. The accuracy of three-dimensional finite element analysis has been assessed by comparing the plane-strain peak stress for an elliptical through-hole with the corresponding plane-strain value from two-dimensional analysis (deviation < 0.1%). Peak stresses at the apex of the elliptical through-hole have also been determined for this three-dimensional mesh assuming a free plate surface. In particular, beside the maximum peak stress and its location, peak stresses have been determined at the surface and at the mid-plane of the plate for thicknesses ranging from 0.2 to 10 times the axis of the elliptical hole. The stress gradients at these locations have been determined, too. The minimum stress gradient is observed at the location of maximum stress. For sufficiently thin and thick plates, the mid-plane stresses approach two-dimensional plane-stress and generalised plane-strain solutions, respectively.

scholarly journals Two - Dimensional Finite Element Analysis of Composite Patch Repairs Using Shell Laminate Elements

2003 ◽  
Vol 12 (2) ◽  
pp. 096369350301200
Author(s):  
George J Tsamasphyros ◽  
George N Kanderakis ◽  
Nikos K Furnarakis ◽  
Zaira P Marioli-Riga
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Element Analysis ◽  
Composite Patch ◽  
Out Of Plane ◽  
Dimensional Finite Element ◽  
Patch Repairs ◽  
Three Dimensional Finite Element

A host of one and two-sided composite patch reinforcements of metallic structures with different patch thickness were considered, in order to compare two-dimensional finite element analysis using shell laminate elements with three-dimensional finite element analysis. In order to verify the accuracy of this approach a parametric study has been performed and the 2D results were compared to the outcome of the corresponding three-dimensional finite element analysis, which accuracy has been experimentally verified in previous works. It was found that for the case of two-sided reinforcement the results obtained by the two methods were in very good agreement. For the case of one-sided reinforcement some deviation of the results of two-dimensional analysis has been observed, which was due to the tendency of the structure for out-of-plane bending, resulting from the bonding of a reinforcing patch to only one face of the structure. According to the results of this parametric study and since most aircraft structures are constrained against local out-of-plane bending (e.g. aircraft skins through stringers) two-dimensional finite elements analysis using shell laminate elements is proposed as an accurate and easy to use analysis tool for the design of both one and two-sided composite patch repairs of relatively simple structures.

Study on Stability of High Embankment with Strong Weathering Filling under Complicated Stress Conditions

2011 ◽  
Vol 97-98 ◽  
pp. 78-84
Author(s):  
Sheng Chuan Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Strength Reduction ◽  
Slope Instability ◽  
Instability Criterion ◽  
Two Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Strength reduction elasto-plastic finite element analysis defines the reduction factor when slope has been destroyed as the slope stability factor of safety, which combines with strength reduction technique, the limit equilibrium theory and the principle of elastic-plastic finite element. Three-dimensional finite element analysis should be used in stability analysis of slope because it can overcome the short advantages of two-dimensional finite element and can simulate the complex topographic and geological conditions. Based on the large-scale triaxial shear test, the modified Duncan-Chang model is established. Based on strength reduction elasto-plastic finite element, stability of high fill embankment was studied with three-dimensional finite element method considering the complex terrain conditions. Study results suggest that plastic strain and displacement mutant of slip surface node can be a sign of slope instability as a whole. At the same time calculation of three-dimensional finite element also does not converge. Therefore, it can be slope instability criterion calculate whether the finite element static analysis converges or not. On the other hand, stability safety factor of high fill embankment under three-dimensional conditions is larger than that of two-dimensional conditions, which shows that boundary conditions of high fill embankment enhance its stability.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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