Optimum Hole Shapes in Finite Plates Under Uniaxial Load

1979 ◽  
Vol 46 (3) ◽  
pp. 691-695 ◽  
Author(s):  
A. J. Durelli ◽  
K. Rajaiah
Keyword(s):  
Stress Concentration ◽  
Fracture Mechanics ◽  
Circular Hole ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Large Range ◽  
Finite Width ◽  
Uniaxial Load ◽  
Circular Holes

This paper presents optimized hole shapes in plates of finite width subjected to uniaxial load for a large range of hole to plate widths (D/W) ratios. The stress-concentration factor for the optimized holes decreased by as much as 44 percent when compared to circular holes. Simultaneously, the area covered by the optimized hole increased by as much as 26 percent compared to the circular hole. Coefficients of efficiency between 0.91 and 0.96 are achieved. The geometries of the optimized holes for the D/W ratios considered are presented in a form suitable for use by designers. It is also suggested that the developed geometries may be applicable to cases of rectangular holes and to the tip of a crack. This information may be of interest in fracture mechanics.

scholarly journals Three-Dimensional Stress Concentration Factor in Finite Width Plates with a Circular Hole

2013 ◽  
Vol 03 (03) ◽  
pp. 153-159 ◽  
Author(s):  
Murilo Augusto Vaz ◽  
Julio Cesar Ramalho Cyrino ◽  
Gilson Gomes da Silva
Keyword(s):  
Stress Concentration ◽  
Circular Hole ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Three Dimensional ◽  
Finite Width

Simple formulae for the stress concentration factor for two- and three-dimensional holes in finite domains

2002 ◽  
Vol 37 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Q. Z Wang
Keyword(s):  
Stress Concentration ◽  
Circular Hole ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Spherical Cavity ◽  
Three Dimensional ◽  
Finite Domain ◽  
Three Dimensional Models ◽  
Finite Domains ◽  
Asymptotic Validity

First, based on an approximate analysis, simple closed-form expressions of the stress concentration factor (SCF) for two- or three-dimensional models with a circular hole or a spherical cavity in a finite domain are derived. Then, an asymptotic method is adopted to improve the accuracy of the derived solutions for an extremely large circular hole or spherical cavity, when the remaining ligament approaches zero. Exact limit SCF values for these two kinds of models were given by Koiter; these values are used for the adjustment of the coefficients in the SCF expressions. Finally, simple SCF formulae for these finite domain problems are obtained, their accuracy is demonstrated to be very good by comparison with the available data from the literature, and the asymptotic validity is guaranteed.

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.

On the Axisymmetrical Stress Concentration at an Eccentrically Reinforced Circular Hole in a Plate

1965 ◽  
Vol 16 (1) ◽  
pp. 15-32 ◽  
Author(s):  
W. H. Wittrick
Keyword(s):  
Stress Concentration ◽  
Circular Hole ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Dimensionless Parameter ◽  
Annular Plate ◽  
Infinite Extent ◽  
Non Linear

SummaryThis paper is concerned with the effectiveness of reinforcing a hole in a plate on one surface only. The particular problem considered is that of a circular hole in a plate of infinite extent, subjected to axially symmetrical tension at infinity, when the reinforcement consists of an annular plate on one surface. Because of the interaction between bending and stretching, the problem is highly non-linear and it has only been possible to solve it for certain limiting cases. The stress concentration factor depends on a dimensionless parameter proportional to the tension at infinity. It is shown that the stress concentration factor is increased, because of the eccentricity of the reinforcement, if the parameter is small, but for values of the parameter greater than a certain minimum the stress concentration factor is decreased. The results also make it quite clear that there is no possibility of obtaining reasonably accurate results by linearisation of the equations.

Finite element analysis on the effect of martensitic transformation and plastic deformation on the stress concentration factor in a thin notched superelastic NiTi ribbon

2020 ◽  
Vol 13 (05) ◽  
pp. 2051028
Author(s):  
Pejman Shayanfard ◽  
Petr Šittner ◽  
Luděk Heller ◽  
Pavel Šandera
Keyword(s):  
Plastic Deformation ◽  
Stress Intensity ◽  
Stress Concentration ◽  
Martensitic Transformation ◽  
Fracture Mechanics ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Stress Intensity Range ◽  
Intensity Range ◽  
Notch Tip

The severe nonlinear behavior caused by the martensitic transformation (MT) and subsequent plastic deformation (PD) of detwinned martensite leads to a complex local stress redistribution at the location of stress risers of superelastic shape memory alloy (SMA) components. Nevertheless, in the literature, the simple linear elastic fracture mechanics (LEFM) equations are widely used in the evaluation of the fracture response of superelastic components which has resulted in obvious conflicts between the conclusions regarding the effect of MT on the fracture parameters, i.e. stress intensity factor (SIF) and material toughness. Furthermore, the linear elasticity method is frequently used in the literature to calculate the stress intensity range ([Formula: see text]) when the fatigue crack growth rate dependence on [Formula: see text] ([Formula: see text]) is being evaluated. Moreover, the PD followed by MT is poorly considered in the fracture mechanics of SMAs. This paper presents a numerical investigation on the role of both MT and PD, as well as the notch acuity, on the evolution of notch-tip stresses and strains and stress concentration factor ([Formula: see text]) upon the incremental application of the macroscopic tensile load on a thin NiTi notched superelastic ribbon, to mimic the effects of MT and PD on the SIF of superelastic parts. It is revealed that MT results in drastic deviations of the notch-tip stress, as well as the stress concentration factor ([Formula: see text]), from that obtained in LEFM. Due to the heterogeneous evolution of MT, the trend of the deviations is not regular and unique upon monotonic external loading. Accordingly, the results represent the ineffectiveness of the LEFM method in the evolution of the stress concentration factor (hence, the SIF) and toughness in monotonic loading, as well as the stress intensity range ([Formula: see text]) under fatigue loading in SMA components.

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