Hole In Flat Plate Research Articles

The Stress Concentration Effect around the Hole in Flat Plate

Using finite element method, models of different element mesh density for the center hole in flat plate were established according to one actual steel plate with central circular hole. The stress concentration coefficients of these models were calculated by means of numerical method. Then the calculated results were compared with the theoretical solution results of Elastic Mechanics. And it was analyzed subsequently that the influences which were caused by different element mesh density on the stress concentration coefficients around the hole in flat plate. The relationship between the element mesh density and the stress concentration coefficients around the hole in flat plate was proposed finally. Results show that the element mesh density for calculation affects the stress concentration coefficients around the hole in flat plate significantly, but the influence is few when the mesh density increases to a certain extent.

On the optimization problem of fillets and holes in plates with curvature constraints

The focus of this study is two-dimensional optimization problem of fillets and holes in plates considering curvature constraints, defined with the goal of minimizing stress concentration factor. The optimality criteria of uniform energy density are extended to shape optimization with curvature constraint assuming that a good shape design can be obtained when constant energy density along the segment of the designed boundary is achieved, except for the section that has to satisfy the geometry constraint. Feasible solutions are sought out under the assumption that the minimum curvature radius is constant on the last part of the designed boundary, and some interesting features of optimal shape of fillets and holes with prescribed minimum curvature radii are revealed. A finite-element-based method in conjunction with a gradientless algorithm is developed to obtain the optimal shape with curvature constraint. Numerical examples of optimal fillets and holes in flat plates are presented to validate the proposed assumption.

Optimal free-form shapes for holes in flat plates under uniaxial and biaxial loading

This paper presents new and transferable design data defining precise optimal free-form shapes for holes in large and finite width plates under biaxial and uniaxial loading conditions respectively. An iterative two-dimensional finite element gradientless shape optimization procedure was used to obtain the optimal shapes, which offer the lowest possible stress concentration, subject to geometric constraints. Precise non-dimensional coordinates are given for a range of hole aspect ratios and are presented in tabular form that allows them to be easily used by designers. The optimal shapes were determined both with and without minimum radius of curvature constraints. Optimal shapes in large plates were found to provide up to a 28 per cent reduction in peak local stress over elliptical shapes of the same aspect ratio. For finite width plates the reduction in peak local stress was as high as 44 per cent. The results obtained are applicable to both the initial design of components with cut-outs and the shape reworking of existing components to remove damage.

Determination of Stress Concentration Factors for Holes in Cylinders Using Thermoelastic Stress Analysis

AbstractThermoelastic stress analysis is used to obtain the stress concentration factors (SCFs) from a variety of circular holes in cylinders. The cylinders are loaded in uniaxial tension, uniaxial compression and a combination of bending and compression. Firstly, radial holes are investigated and the results from the thermoelastic data obtained by the SPATE equipment are compared with previous experimental and numerical work. SCFs are then obtained from offset, oblique and offset–oblique holes using the Deltatherm system. The effect of hole obliquity and direction of applied load relative to the hole geometry are discussed in detail. Finally, the results from the cylinders are compared with predictions of the SCFs in cylinders from a previous study of oblique holes in flat plates.

Thermoelastic stress analysis of oblique holes in flat plates

The stresses in the region of an oblique hole in a flat plate are analysed using the thermoelastic stress analysis technique. Particular attention is given to the obliquity of the hole and to the line of action of the applied load in relation to the hole axes. The effects of varying plate thickness are also studied. The data from around the rim and along the internal axis of the hole are presented as a series of stress concentration factors. The results are compared to those from previous studies and discussed in detail. These confirm the findings of the previous work in that increases in hole obliquity increase the stress at the hole, the maximum principal stress is obtained when the load is applied normal to the major axis of the surface ellipse and that as the thickness of plate increases the stresses on the surface of the plate decrease. Issues such as differences in the material’s Poisson’s ratio value are also discussed. The effect of any non-adiabatic behaviour on the thermoelastic output is described.

Quarter Elliptical Cracks Emanating From Holes in Plates

The finite element-alternating method, a linear elastic solution technique, is refined and applied to problems of quarter-elliptical cracks in irregular bodies. The method involves the iterative superposition of a finite element solution for stresses in an unflawed body and an analytic solution for stresses in an infinite solid containing a flat elliptical crack. Mode-one stress intensity factors are presented along the periphery of quarter-elliptical cracks emanating from open fastener holes in flat plates. Results are shown for a variety of crack geometries and two hole-diameter to plate-thickness ratios. Comparisons are made with experimental results of other authors.

Equivalent reinforcement of holes in flat plates

Equivalent reinforcement of holes in flat plates

A novel comparator fpr the location of edges and holes in plates

The author previously described a novel method of comparing the positions of small holes in flat plates (see abstr. A74044 of 1974). The method has now been extended to compare the positions of straight edges on such components.

Stress distribution around large holes in flat plates

Employing a special case of a new method, the solution for the problem of a rectangular flat plate with a central large circular cutout subject to some transverse load and/or moment is derived. This is achieved with the use of certain eigenfunctions generated by sets of circular line loadings of the plate. Numerical results are presented for special cases.

A Study of the Stresses Around Elliptical Holes in Flat Plates

The theoretical elastic stress distribution is presented for a thin flat plate of finite width which contains an elliptical hole. Various uniaxial and biaxial in-plane loads are applied to the plate and the results are compared with some existing experimental work. The results of a series of photoelastic tests which were arranged to examine the interaction between the stresses around two neighboring elliptical holes in flat plates are also presented.

Reduction of Alternating Stress Range Around Holes in Flat Plates by Use of Inserts

Airy stress functions are established herein for the solution of hollow annular interfering inserts in thin flat plates which extend to infinity. The equations presented are solved for the case of a non-circumferential-slip insert to plate interface in a uniaxial stress field. The solution assumes plane stress and yields the stress and displacement fields for both plate and insert. The interface friction coefficient necessary to enforce the nonslip condition is determined as a function of initial interference. The analysis is extended to the case of a biaxial stress field through the use of superposition. The results indicate that inserts can be used to significantly reduce the maximum alternating stress range induced by plate load fluctuations. Curves are presented which may be easily applied to the design of inserts for the most effective reduction of alternating stress ranges around holes that could otherwise be a potential cause of failure due to low-cycle fatigue.

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

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.