Stress Concentration Factors For Plates Research Articles

Theoretical and simulation of central elliptical hole with rectangular plate

A study on design engineering components with slot, notches is very important, because there is a stress increases/failure region area, where the force/stress is concentrating more and more. The elastic stress concentration mainly depends on the mode of loading, materials, and geometry of the design engineering components. The design engineers, academicians, and researchers concentrated and focused on fail-safe design and safe life design. A Plate is considered with different slots, such as circular and elliptical. The main objective of this study is to find out the stress concentration factor in plates with various cutout shapes. This concept is used in design components/structures, for finding the elastic stress concentration. The methods compared are tabulated with their findings. Singularities of the circular hole and elliptical hole in rectangular plates are considered in the present study. The finite Element Method (FEM) was used for fine mesh and ANSYS WORKBENCH software was used for extracting the results and results were validated by analytical or experimental methods.

Stress concentration around perforations produced by corrosion in steel storage tanks

This paper presents numerical results of stress concentration factors for plates perforated by corrosion. Evidence from 25 plates with corrosion perforation considered show that typical shapes may be characterized as a deviation from an ellipse or from a circle. In order to model typical perforations created by this type of corrosion, holes with non-circular boundaries have been considered in the form of cosine shape and variations from it. Two load cases are investigated: uniaxial and shear stress fields in an elastic plane stress problem. The influence of the amplitude of deviation with respect to an ellipse or circle and the local curvature of the internal boundary of the hole are studied. A simplified model of an equivalent ellipse originally proposed by Nishida is shown to provide good estimates for stress concentration factors for a range of shapes induced by corrosion.

Stress concentration factor in plates with transverse butt-weld misalignment

Misalignment at butt-welded joints induces bending stresses with the application of in-plane loads only. This stress concentration will have a detrimental effect on both the ultimate strength of the plate and the fatigue strength at the weld. The stress concentration factor is often represented as K=1+ C( e/ t), where C is called the stress concentration coefficient in this paper. In the current literature it is found that different values of C have been used, none of which were derived by the plate theory. In this paper, a linear elastic stress analysis of ship plates with a tranverse butt-weld misalignment under uniaxial compression is carried out. It is found that the stress concentration coefficient C is not a constant, but varies with the aspect ratio, the location of the misalignment in the plate and the magnitude of the nominal applied stress.

Actual three-dimensional stresses in notches, crack tips and lamination planes

A strange dichotomy exists in the analysis of stresses in local effects and in adhesively bonded parts. It has been known in aeronautical engineering for at least 60 years that the stresses in plates with notches or cracks, or in plates subjected to localized loads, are strongly three-dimensional. Nevertheless, it has been common to invoke the notion of the so-called generalized plane stress state , and to consider the two-dimensional treatment of the stress states in regions of notches, cracks or lamination planes to be completely satisfactory. As a result, many analytical solutions in stress analysis are not testable—the errors are both in the magnitude, up to 30%, and even in the sign. Two problems have developed, one practical, the other aesthetic. First, for obvious reasons, modern technology needs analytical solutions, or computer programs, which simulate reliably the actual physical occurrence. Second, any analytical solution which ignores one or more basic features of the real behavior of materials and bodies under consideration, or is incompatible with some underlying assumptions, or violates some principles of mechanics, is not only insufficiently reliable but cannot be considered elegant. Using Popper's terminology, such a solution is not in the category of a physical theory but is rather in the category of a metaphysical theory. The paper presents selected examples of empirical evidence on the actual, mostly three-dimensional, stresses in notches, cracks, beams with local effects, and in components of adhesively bonded joints . The usefulness of the renormalization procedures for singular solutions is discussed, and more comprehensive and realistic notions of the stress concentration factor in plates are suggested.

Strains and stress-concentration factors in plates under out-of-phase biaxial cyclic loads

An elastic theoretical analysis for the strains in an infinite plate and the stress-concentration factors for small elliptical holes in an infinite plate, under sinusoidally varying alternating out-of-phase biaxial loads, is presented. The experiments were performed to substantiate a theoretical analysis for circular and elliptical holes by means of a specially designed and built ‘biaxial cyclic stress machine’. For biaxial alternating stresses, the stress-concentration factor is defined as the ratio of the amplitude of the maximum alternating stress around the geometrical discontinuity to the larger of the amplitudes of the two principal alternating stresses which would occur at the same point if the geometrical discontinuity were not present. Both values are considered over a stress cycle. The results of the theoretical analysis are presented in the form of curves which show the effect of phase differences between stresses and strains upon stress ratio and cyclic stress-concentration factors. The test results of the experiments are also summarized in the form of the curves. Since the experiments were performed on a finite plate compared to an infinite plate considered for theoretical analysis, the experimental curves do not coincide with the theoretical curves. But in general the experimental curves follow the same trends as the theoretical curves. Fatigue implications of out-of-phase biaxial cyclic loads are discussed.

The effect of low-frequency biaxial loads on stress-concentration factors in plates

It is generally recognized that stress-concentration factors under stress-wave loading are lower than those under static loads. In this work, the effect of low-range frequency of biaxial sinusoidally varying alternating stresses on the stress-concentration factors for circular and elliptical holes in Plexiglas plates is investigated. The experiments have been performed on a specially designed and built “biaxial cyclic-stress machine” and the results are presented in the form of curves. In the case of biaxial alternating stresses, the stress-concentration factor is defined as the ratio of amplitude of the maximum alternating stress around the geometrical discontinuity to the larger of the amplitudes of the two principal alternating stresses which would occur at the same point, if the geometrical discontinuity was not present. Both values are considered over a stress cycle. The results indicate a slight decrease in the values of stress-concentration factors with increase in frequency.