Corrosion Effects on Reliability of Flat Plates in Tension

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Weiwei Yu ◽  
Dale G. Karr ◽  
Pedro M. Vargas
Keyword(s):  
Stress Concentration ◽  
Limit State ◽  
Analytical Formula ◽  
Safety Index ◽  
Structural Failure ◽  
Safety Factors ◽  
Flat Plates ◽  
Partial Safety Factors ◽  
Concentration Factors ◽  
Stress Concentration Factors

Neuber’s theory of elastic and inelastic stress concentration factors are applied to the pit corrosion of plates. The finite element method is then employed to model the problem numerically and to calculate the stress concentration factors for semioblate spheroidal pits. Furthermore, corrosion development is a process with many random factors such as the geometry and the growth rate. A realistic reflection of corrosion effects on structural failure is to consider it within the framework of reliability analysis. By knowing the analytical formula of stress concentration factor, reliability analyses are conducted to calculate the reliability safety index of the panel based on a strain-based limit state. The structural failure can then be directly related to the reliability safety index. The reliability procedure is demonstrated in an example of a highly deformed bottom shell panel during ship grounding. Partial safety factors of two random variables which describe pit corrosion geometry and the effective nominal strain level are also calculated. Recommendations for using partial safety factors are provided.

Stress Analysis of Holes in Thick Plates

2004 ◽  
Vol 1-2 ◽  
pp. 153-158 ◽  
Author(s):  
S. Quinn ◽  
Janice M. Dulieu-Barton
Keyword(s):  
Stress Concentration ◽  
Stress Analysis ◽  
Uniaxial Tension ◽  
Plane Stress ◽  
Plate Surface ◽  
Flat Plates ◽  
Thick Plates ◽  
Concentration Factors ◽  
Stress Concentration Factors

A review of the Stress Concentration Factors (SCFs) obtained from normal and oblique holes in thick flat plates loaded in uniaxial tension has been conducted. The review focuses on values from the plate surface and discusses the ramifications of making a plane stress assumption.

Stress concentration caused by an oblique round hole in a flat plate under uniaxial tension

1968 ◽  
Vol 3 (2) ◽  
pp. 98-102 ◽  
Author(s):  
H W McKenzie ◽  
D J White
Keyword(s):  
Stress Concentration ◽  
Maximum Stress ◽  
Elliptical Hole ◽  
Round Hole ◽  
Flat Plates ◽  
Reasonable Estimate ◽  
Load Carrying ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Plate Width

Stress-concentration factors have been determined for oblique holes in flat plates by a method using frozen-stress photoelasticity. The ellipses formed at the intersection of the hole and the plate surfaces had their major axes perpendicular to the direction of application of the load. The maximum stress-concentration factor was found to increase with increasing angle of obliquity with respect to the normal to the plate but the experimental factors were found to be considerably lower than those predicted from a theory of Ellyin et al. Graphs are given which enable maximum stress-concentration factors to be obtained for oblique holes having a ratio of hole diameter to plate width of 0.1. It was found that, for the models tested, elliptical hole data gave a reasonable estimate of the maximum stress-concentration factors based on net area. Removing the feather edge of the hole, by applying various edge radii, did not alter the stress concentration appreciably except in so far as load-carrying area was reduced.

scholarly journals Stress Concentration Factors for Welded Plate T-Joints Subjected to Tensile, Bending and Shearing Loads

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 546
Author(s):  
Krzysztof L. Molski ◽  
Piotr Tarasiuk
Keyword(s):  
Stress Concentration ◽  
Plate Thickness ◽  
Percentage Error ◽  
Geometrical Parameters ◽  
T Joints ◽  
Loading Mode ◽  
Weld Toe ◽  
Concentration Factors ◽  
Parametric Expression ◽  
Stress Concentration Factors

The paper deals with the problem of stress concentration at the weld toe of a plate T-joint subjected to axial, bending, and shearing loading modes. Theoretical stress concentration factors were obtained from numerical simulations using the finite element method for several thousand geometrical cases, where five of the most important geometrical parameters of the joint were considered to be independent variables. For each loading mode—axial, bending, and shearing—highly accurate closed form parametric expression has been derived with a maximum percentage error lower than 2% with respect to the numerical values. Validity of each approximating formula covers the range of dimensional proportions of welded plate T-joints used in engineering applications. Two limiting cases are also included in the solutions—when the weld toe radius tends to zero and the main plate thickness becomes infinite.

Stress concentration factors for the torsion of curved beams of arbitrary cross-section

2006 ◽  
Vol 220 (12) ◽  
pp. 1709-1726 ◽  
Author(s):  
R E Cornwell
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Cross Section ◽  
Cross Sections ◽  
Shear Stresses ◽  
Curved Beams ◽  
Finite Element Implementation ◽  
Out Of Plane ◽  
Concentration Factors ◽  
Stress Concentration Factors

There are numerous situations in machine component design in which curved beams with cross-sections of arbitrary geometry are loaded in the plane of curvature, i.e. in flexure. However, there is little guidance in the technical literature concerning how the shear stresses resulting from out-of-plane loading of these same components are effected by the component's curvature. The current literature on out-of-plane loading of curved members relates almost exclusively to the circular and rectangular cross-sections used in springs. This article extends the range of applicability of stress concentration factors for curved beams with circular and rectangular cross-sections and greatly expands the types of cross-sections for which stress concentration factors are available. Wahl's stress concentration factor for circular cross-sections, usually assumed only valid for spring indices above 3.0, is shown to be applicable for spring indices as low as 1.2. The theory applicable to the torsion of curved beams and its finite-element implementation are outlined. Results developed using the finite-element implementation agree with previously available data for circular and rectangular cross-sections while providing stress concentration factors for a wider variety of cross-section geometries and spring indices.

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