Theoretical Stress Concentration Factors for Short Rectangular Plates With Centered Circular Holes

1999 ◽  
Vol 124 (1) ◽  
pp. 126-128 ◽  
Author(s):  
N. Troyani ◽  
C. Gomes ◽  
G. Sterlacci
Keyword(s):  
Stress Concentration ◽  
Rectangular Plates ◽  
The Finite Element Method ◽  
New Concepts ◽  
Circular Holes ◽  
Transition Length ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Theoretical Stress ◽  
Theoretical Stress Concentration Factor

This work shows that the theoretical stress concentration factor depends on the length of the member in addition to the established other standard geometric parameters. In particular, the in-plane theoretical stress concentration factors for short rectangular plates with centered circular holes subjected to uniform tension are determined using the finite element method. It is shown that these factors can reach significantly larger values than the corresponding existing ones for long plates. The value of the transition length between long and short plates is computed and reported as well. Two new concepts are defined, short members and transition length.

Howland’s isotropic Kts curve for plates with circular holes as a master curve for Kts in orthotropic plates with elliptical holes

2017 ◽  
Vol 52 (3) ◽  
pp. 152-161 ◽  
Author(s):  
Nando Troyani ◽  
Milagros Sánchez
Keyword(s):  
Stress Concentration ◽  
Master Curve ◽  
Orthotropic Materials ◽  
Finite Width ◽  
Rectangular Plates ◽  
Analysis And Design ◽  
Circular Holes ◽  
Elliptical Holes ◽  
Concentration Factors ◽  
Stress Concentration Factors

The importance of the role played by the so-called stress concentration factors (or symbolically referred to as Kts) in analysis and design in both mechanical and structural engineering is a well-established fact, and accuracy and ease in their estimation result in significant aspects related to engineering costs, and additionally on both the reliability in the design of parts and/or in the analysis of failed members. In this work, rectangular finite width plates of both isotropic and orthotropic materials with circular and elliptical holes are considered. Based on two key observations reported herein, it is shown in a partially heuristic engineering sense, that Howland’s solution curve for the stress concentration factors for finite width plates with circular holes subjected to tension can be viewed as a master curve; accordingly, it can be used as a basis to rather accurately estimate stress concentration factors for isotropic finite width tension rectangular plates with centered elliptical holes and also rather accurately used to estimate stress concentration factors for orthotropic finite width rectangular plates under tension with centered elliptical holes. Two novel concepts are defined and presented to this effect: geometric scaling and material scaling. In all the examined and reported cases, the specific numerical results can be obtained accurately using a hand-held calculator making virtually unnecessary the need to program and/or use other complex programs based on the finite element method, just as an example. The maximum recorded average error for all the considered cases being 2.62% as shown herein.

Theoretical stress concentration factors for short flat tension bars with opposite U-shaped notches

2005 ◽  
Vol 40 (4) ◽  
pp. 345-355 ◽  
Author(s):  
C J Gomes ◽  
N Troyani ◽  
C Morillo ◽  
S Gregory ◽  
V Gerardo ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Stress Concentration ◽  
Graphical Form ◽  
Uniform Thickness ◽  
Uniform Tension ◽  
Extended Range ◽  
Transition Length ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Theoretical Stress

The values of the theoretical stress concentration factors for a number of geometries and loads are available in well-known publications. It is shown here that the reported existing results for the geometry treated herein do not account for the effect of the length of the members in the direction of the applied loads, and it is also shown that shorter lengths may have important effects on the magnitudes of the stress concentration factors, a concept widely used in fatigue applications. The finite-element-determined in-plane theoretical stress concentration factors for short rectangular uniform thickness plates, with opposite U-shaped notches, subjected to uniform tension, for the existing range of the notch radii values as well as for an extended range of these values are reported and are presented in the standard graphical form. Other types of boundary condition have been examined as well in this work with various influences on the stated factor. The transition length concept, the dividing threshold between long and short plates is revised, and the corresponding values are reported as well.

Theoretical stress concentration factors for short shouldered plates subjected to uniform tension

2003 ◽  
Vol 38 (2) ◽  
pp. 103-113 ◽  
Author(s):  
N Troyani ◽  
A Marín ◽  
H García ◽  
F Rodríguez ◽  
S Rodríguez ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Stress Concentration ◽  
Graphical Form ◽  
Uniform Thickness ◽  
Uniform Tension ◽  
Transition Length ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Theoretical Stress

The values of the theoretical stress concentration factors for a variety of geometries and loads are available in a number of well-known publications. It is shown in this work that the reported existing results neglect the length of the members in the direction of the applied loads, and it is also shown that shorter lengths may have very significant effects on the magnitudes of the stress concentration factors. The finite element determined in-plane theoretical stress concentration factors for uniform thickness short shouldered plates subjected to uniform tension at the wide end and held longitudinally at the narrow end, for practical ranges of the fillet radius values, are reported and are presented in the standard graphical form. For completeness, other types of boundary condition have also been examined in this work. The value of the transition length between long and short plates is reported as well.

Stress Concentration Factors in Auxetic Rods and Plates

2013 ◽  
Vol 394 ◽  
pp. 134-139 ◽  
Author(s):  
Teik Cheng Lim
Keyword(s):  
Stress Concentration ◽  
Circumferential Stress ◽  
Axial Direction ◽  
Thin Plates ◽  
Auxetic Materials ◽  
Circular Holes ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Future Work ◽  
Poissons Ratio

Auxetic materials are solids that possess negative Poissons ratio. Although rare, such materials do occur naturally and also have been artificially produced. Due to their unique properties, auxetic materials have been extensively investigated for load bearing applications including in biomedical engineering and aircraft structures. This paper considers the effect of Poissons ratio on the stress concentration factors on rods with hyperbolic groove and large thin plates with circular holes and rigid inclusions. Results reveal that the use of auxetic materials is useful for reducing stress concentration in the maximum circumferential stress of the rods with grooves, and in plates with circular holes and rigid inclusions. However, the use of auxetic materials increases the stress concentration in the axial direction of the rod. Therefore a procedure to accurately select and/or design materials with precise negative Poissons ratio for optimal design is suggested for future work.

The Stress Concentration Factors in Cylindrical Tubes with Transverse Circular Holes

1959 ◽  
Vol 10 (4) ◽  
pp. 326-344 ◽  
Author(s):  
H. T. Jessop ◽  
C. Snell ◽  
I. M. Allison
Keyword(s):  
Stress Concentration ◽  
Maximum Stress ◽  
Stress System ◽  
Complete Knowledge ◽  
Geometrical Shapes ◽  
Cylindrical Tubes ◽  
Circular Holes ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Better Than

The “frozen stress” techniques of photoelasticity can give a complete knowledge of the stress, system in a solid body, but the examination of the stresses requires more time and care than in corresponding flat plate tests. In tests on tubes with transverse circular holes, sponsored by The Royal Aeronautical Society, all practicable geometrical shapes are examined and the maximum stress is measured in tension, bending and torsion. The results are comprehensive and show the inadequacy of previous results. In all cases the maximum stress occurs inside the bore of the hole. The accuracy of all the graphs of stress concentration factors is better than five per cent.

Stress concentrations due to axial tension and bending of loaded axisymmetric projections

1983 ◽  
Vol 18 (1) ◽  
pp. 7-14 ◽  
Author(s):  
T H Hyde ◽  
B J Marsden
Keyword(s):  
Stress Concentration ◽  
Diameter Ratio ◽  
The Finite Element Method ◽  
Stress Concentrations ◽  
Axial Tension ◽  
Bending Loads ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
D Values ◽  
Existing Data

The finite element method has been used to investigate the behaviour of axisymmetric loaded projections (e.g., bolts) subjected to axial tension and bending. The results show that existing data for stepped shafts, which have the axial tension and bending loads applied remote from the region of the step, cannot be applied to loaded projections with the same geometry. For h/d (head thickness to shank diameter ratio) values greater than 0.66 and 0.41 for axial tension and bending, respectively, the stress concentration factors are independent of h/d, load position, and D/d (head diameter to shank diameter ratio) for D/d in the range 1.5 ≤ D/d ≤ 2.0. Smaller h/d values result in large increases in the stress concentration factors due to dishing of the head.

Orthotropy and geometry effects on stress concentration factors for short rectangular plates with a centred circular opening

2007 ◽  
Vol 42 (7) ◽  
pp. 551-555 ◽  
Author(s):  
K Bakhshandeh ◽  
I Rajabi
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Finite Width ◽  
Rectangular Plates ◽  
Circular Opening ◽  
Orthotropic Plates ◽  
Plate Length ◽  
Transition Length ◽  
Stress Concentration Factors

In this study, the effects of orthotropy ratio and plate length on the stress concentration factor for orthotropic plates with a centred circular opening under the action of uniaxial tension loads are investigated by use of the finite element method. This work demonstrates that the stress concentration factor depends on the length of the member in addition to other established geometric parameters. The value of the transition length between long and short plates is computed and reported as well. This study has shown that Tan's equation for a finite width orthotropic plate is accurate for a ratio of the opening radius to plate semiwidth of less than 0.35 for orthotropy ratios less than 50. A new concept is introduced, namely the transition ratio.

The Use of Stress Reduces in suddenly Changed Section of Rounded Shafts

2011 ◽  
Vol 147 ◽  
pp. 9-13
Author(s):  
S.R. Mohebpour ◽  
Mohammad Vaghefi
Keyword(s):  
Stress Concentration ◽  
Numerical Optimization ◽  
Optimization Approach ◽  
Geometrical Shape ◽  
New Concepts ◽  
Concentration Factors ◽  
Geometrical Change ◽  
Stress Concentration Factors ◽  
Reducing Stress ◽  
Dangerous Section

Reducing stress concentration is mainly done by fillets. However, new concepts toward better material properties lead designers and engineers to use these materials in their design, still changing in geometrical shape of desired models can help us in reducing stress concentration factors. New devices, including fast computers, reliable numerical methods (FEM), and numerical optimization approach can bring special devices for better designing besides considering design limitations in special industries. In this paper we focus on geometrical change (rounded groove) in the sudden changed section of the rounded shaft to reduce stress concentration in the most dangerous section. By optimizing this proposed change in the geometry of shaft we reduce the stress, so using of fillets can be neglected in the future designs to prevent metallurgical and design limitations.

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