Some Modeling Issues on the Finite Element Computation of Thermal Stresses in Metal Lines

1993 ◽  
Vol 115 (4) ◽  
pp. 392-403 ◽  
Author(s):  
Arturo O. Cifuentes ◽  
Iqbal A. Shareef
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Geometric Nonlinearity ◽  
Thermal Stresses ◽  
Element Computation ◽  
Element Technique ◽  
Versus Plane ◽  
Evolving Models ◽  
Finite Element Computation

Thermal stresses are a major concern in the reliability of metal lines. This paper addresses some modeling issues concerning the determination of thermal stresses in such structures. Specifically, a finite element technique that allows one to follow the evolution of the stress field as a function of the steps of the manufacturing process is discussed. In addition, comparisons between several modeling strategies, namely, plane stress versus plane strain, geometric nonlinearity versus geometric linearity, “frozen view” models versus “evolving” models, etc., are presented. A detailed example describing the manufacturing of a copper line is included to illustrate these points.

Estimating Lower Bound Limit Loads: No Iterations/Modulus Adjustment

2012 ◽  
Author(s):  
C. Hari Manoj Simha ◽  
Reza Adibi-Asl
Keyword(s):  
Finite Element ◽  
Lower Bound ◽  
Stress Field ◽  
Ad Hoc ◽  
Elastic Stress ◽  
Limit Loads ◽  
Variational Form ◽  
Element Computation ◽  
Modulus Reduction ◽  
Finite Element Computation

We use the extended variational form of Mura and co-workers to estimate the lower bound limit loads for structures acted upon by a single load. Our scheme requires one elastic stress field either from a conventional finite element computation or analytical solution. No iterative stress field adjustments are required. We also adapt the scheme for structures with flaws by advancing a criterion that may be used to select sub-volumes of the structure that do not participate in the collapse. For structures with flaws, no ad hoc elastic modulus reduction at the stress concentration is required. Application of the proposed method is illustrated for some typical flawed and flaw-free structures and it is shown that the obtained multipliers are not overly conservative.

Determination of Stress Concentration Around an Oblique Hole by a Finite-Element Technique

1983 ◽  
Vol 105 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Hua-Ping Li ◽  
F. Ellyin
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Maximum Stress ◽  
Plate Thickness ◽  
Two Dimensional ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Parametric Studies ◽  
Element Technique

A plate weakened by an oblique penetration of a circular cylindrical hole has been investigated. The stress concentration around the hole is determined by a finite-element method. The results are compared with experimental data and other analytical works. Parametric studies of effects of angle of inclination, plate thickness, and width are performed. The maximum stress concentration factor (SCF) obtained from the finite-element analysis is higher than experimental results, and this deviation increases with the increase of angle of skewness. The major reason for this difference is attributed to the shear-action between layers parallel to the plate surface which cannot be directly included in the two-dimensional elements. An empirical formula is derived which accounts for the shear-action and renders the finite-element predictions in line with experimentally observed data.

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