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Summary Based on the theory of finite deformations and by the use of a given reference frame in undeformed body, stresses of an incompressible isotropic infinite plate with two circular holes subjected to biaxial tension at infinity are investigated. The material is assumed to be in the state of finite plane strain. The method of successive approximation is used in connection with the complex variable method of plane elasticity. Numerical results due to the second-order approximation theory are given for stresses, and compared with those predicted by classical theory of elasticity.
Übersicht Es werden die Spannungen in einer unendlich ausgedehnten Platte mit zwei kreisförmigen Löchern nach der Theorie endlicher Verformungen und unter Verwendung eines im unverformten Körper festgelegten Bezugsgerüstes untersucht. Die Platte besteht aus inkompressiblem isotropen Material und wird einer im Unendlichen zweiachsialen Verzerrung ausgesetzt. Der Verzerrungszustand wird als eben angenommen. Bei den Untersuchungen werden die komplexen Methoden der ebenen Elastizitätstheorie in Verbindung mit schrittweisen Näherungen angewendet. Aufgrund einer Annäherung zweiter Ordnung werden die Spannungen numerisch ausgerechnet und mit den Werten verglichen, die von der klassischen Elastizitätstheorie vorausgesagt werden.


The author wishes to express his hearty thanks to Osamu Tamate, Professor of Tohoku University, for directing the work.  相似文献   

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The object of the work described was to obtain information about the stresses in reinforced plastic bars. Tests were carried out under bending on a bar with a composite reinforced semicircular notch. The bars were of epoxy resin reinforced with duralumin. The reinforcements are the concentric, crescent and arch types. The relations between the maximum shear stress and breadth of bars are obtained. The most suitable reinforcements are discussed.  相似文献   

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The effect of superimposed hydrostatic pressure on fracture in round bars under tension is studied numerically using the finite element method based on the Gurson damage model. It is demonstrated that while the superimposed hydrostatic pressure has no noticeable effect on necking, it increases the fracture strain due to the fact that a superimposed pressure delays or completely eliminates the nucleation, growth and coalescence of microvoids or microcracks. The experimentally observed transition of the fracture surface, from the cup-cone mode under atmospheric pressure to a slant structure under high pressure, is numerically reproduced. It is numerically proved that the superimposed hydrostatic pressure has no effect on necking for a damage-free round bar under tension.  相似文献   

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The first attempt of finding of optimal shape for bars in presence of body forces with respect to mixed creep rupture is made. For given volume of the bar, distribution of initial cross-section, ensuring the longest life-time to mixed rupture is sought. The finite strain theory and physical law in form of Norton's law generalized for true stresses and logarithmic strains are applied. Using the method of parametric optimization, the best of linear and quadratic functions describing the initial shape of the bar are found. The shape of initial strength is corrected in a way leading to longer life-time. Results of both approaches are compared.  相似文献   

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Hole shapes are optimized in circular cylindrical shells subjected to axial load considering only the predominantly large membrane stresses present around the holes. Two-dimensional photoelastic isochromatics obtained with a special-purpose polariscope are utilized for the optimization process. The process leads to a significant decrease in the membrane stress-concentration factor and a modest decrease in weight, thus yielding a considerable increase in strength-to-weight ratio. This paper presents results for certain typical ratios of hole diameter to shell diameter. Previous theoretical and experimental studies for the circular hole have also been verified  相似文献   

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The elastoplastic state of thin conical shells with a circular hole is analyzed assuming finite deflections. The distributions of stresses, strains, and displacements along the hole boundary and in the zone of their concentration are studied. The stress–strain state of shells around the hole under axial tension is analyzed taking into account two nonlinear factors. The numerical results are presented as plots and tables  相似文献   

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The elastoplastic state of cylindrical shells with a circular hole is studied considering finite deflections. The material of the shells is isotropic and homogeneous; the load is axial tension. The distribution of stresses, strains, and displacements along the hole boundary and in the zone of their concentration is studied by solving a doubly nonlinear problem. The data obtained are compared with the solutions of the physically and geometrically nonlinear problems and a numerical solution of the linear elastic problem __________ Translated from Prikladnaya Mekhanika, Vol. 44, No. 7, pp. 101–109, July 2008.  相似文献   

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In the present paper by using complex variable methods in linear elasticity and by means of analytic continuation, the author obtains for this problem a complex torsional function, shear stress components, displacement components,the torsional rigidity and shear stresses on boundaries expressed in terms of series.  相似文献   

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A two-dimensional photoelastic study was made of the stress-concentration factor,k, in a statically loaded tensile strip of widthW, with a central circular hole of diameterD, to determine the value ofk asD/W→1. Here, \(k = \sigma _{\max } /\sigma _{nom}\) where \(\sigma _{\max }\) is the maximum stress at the hole and \(\sigma _{nom}\) is the nominal or average stress on the net cross-sectional area. Eight stress-concentration experiments were performed for 0.50≤D/W≤0.99, and it was found thatk→2 asD/W→1.  相似文献   

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田宗漱  高陆 《计算力学学报》2000,17(4):483-486496
根据Hellinger-Reissner原理建立了具有一个无外力圆柱表面的三维八节点杂交应力元,其假设应力场严格满足柱坐标下三维平衡方程及圆柱面上无外力边界条件;当元退化为二维时也满足协调方程。数值算例表明,这种特殊杂交应力元可高效地分析具有两个圆孔薄板和厚板的应力集中,特别是三维应力集中。  相似文献   

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It has been known for some time that under certain circumstances the axisymmetric solution describing the deformation experienced by a stretched circular thin plate or membrane under sufficiently strong normal pressure does not represent an energy-minimum configuration. By using the method of adjacent equilibrium a set of coordinate-free bifurcation equations is derived here by adopting the Föppl–von Kármán plate theory. A particular class of asymmetric bifurcation solutions is then investigated by reduction to a system of ordinary differential equations with variable coefficients. The localised character of the eigenmodes is confirmed numerically and we also look briefly at the role played by the background tension on this phenomenon.  相似文献   

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The purpose of this investigation was to determine more accurately the stress concentrations in tensile strips having large circular holes where the ratio of the hole diameter to strip width is greater than 0.5 Results of numerical elasticity analyses are presented for ratios of hole diameter to bar width ranging from 0.10 to 0.99, and photoelastic data are presented for the range from 0.40 to 0.94. Both numerical results and photoelastic data indicate that the stress-concentration factor based on net area approaches a value of one as the ratio of hole diameter to bar width approaches a value of one.  相似文献   

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