Elasto-Plastic Analysis of Perforated Plates Containing Triangular Penetration Patterns of 10 Percent Ligament Efficiency

1979 ◽  
Vol 101 (3) ◽  
pp. 210-215 ◽  
Author(s):  
D. P. Jones ◽  
J. L. Gordon
Keyword(s):  
Work Hardening ◽  
Pure Shear ◽  
Perforated Plate ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Hardening Material ◽  
Perforated Plates ◽  
Solid Plate ◽  
Deformation Plasticity ◽  
Concentration Factors

The finite element method is utilized to obtain the elasto-plastic stress and strain fields in a perforated plate made of a work-hardening material. The perforated plate contains penetrations arranged in a triangular pattern with a ligament efficiency of 10 percent and is considered to be in a state of plane stress. Stress distributions as well as strain concentration factors are presented for the two orthogonal uniaxial and the pure shear load cases. Effective elasto-plastic equivalent solid plate properties are presented in terms of Hill’s anisotropic deformation plasticity theory. The localized stress and plastic strain distributions are discussed in terms of the work-hardening characteristics of the material. Conclusions are drawn relevant to the plastic design and analysis of perforated plates.

Plastic Strain Concentrations in Perforated Structures Subjected to Alternating Loads

1982 ◽  
Vol 104 (3) ◽  
pp. 161-167 ◽  
Author(s):  
R. D. Kichko ◽  
M. Badlani ◽  
F. Spaniel ◽  
W. J. O’Donnell ◽  
J. S. Porowski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Plastic Strain ◽  
Shear Loading ◽  
Monotonic Loading ◽  
The Finite Element Method ◽  
Perforated Plates ◽  
Strain Concentration ◽  
Elastic Plastic ◽  
Concentration Factors

Perforated plates with a uniform triangular penetration pattern subjected to alternating loads are analyzed. The cases of equibiaxial and shear loading are considered and the finite element method is used to obtain elastic-plastic solutions for various ligament efficiencies. The plastic strain concentrations for alternating loads are compared to those for monotonic loading. Useful methods of obtaining plastic strain concentration factors for alternating loads using the results for monotonic loading are given.

In-Plane Torsion Testing of Sheet Metal

1977 ◽  
Vol 19 (5) ◽  
pp. 213-220 ◽  
Author(s):  
R. Sowerby ◽  
Y. Tomita ◽  
J. L. Duncan
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Work Hardening ◽  
Finite Element Approximation ◽  
Stress And Strain ◽  
Element Approximation ◽  
The Finite Element Method ◽  
Hardening Material ◽  
Torsion Testing ◽  
Stress And Strain Distribution

In this paper, the ‘in-plane’ torsion testing of sheet metal is examined. The test itself was first proposed by Marciniak in order to ascertain the work hardening behaviour and fracture strain of sheet metals. In the original work, the analysis was based on the assumption that the material was rigid-work hardening. The present work attempts a more rigorous solution, assuming the material to be elastic-work hardening. A finite-element approximation is employed to calculate the stress and strain distribution across the sheet metal annulus at various stages in the deformation process. A comparison is made between the results from the finite-element method and those based on a rigid-work hardening material. For certain annulus geometries, excellent agreement is obtained between both sets of results.

Study on Equivalent Stress to Control Average Inelastic Behavior of Perforated Plates

2014 ◽  
Author(s):  
Yeldos Kultayev ◽  
Naoto Kasahara
Keyword(s):  
Stress Ratio ◽  
Elevated Temperatures ◽  
Equivalent Stress ◽  
Perforated Plate ◽  
Estimation Method ◽  
Inelastic Behavior ◽  
Perforated Plates ◽  
Inelastic Analysis ◽  
Solid Plate ◽  
Simple Models

Next generation reactors which are subjected to elevated temperatures must be designed to account for inelastic deformation along with elastic one. In order to simplify design analysis of perforated portions, conventionally axisymmetric models with equivalent elastic materials are employed. To extend to inelastic analysis, a method of Effective Stress Ratio (ESR) has been studied in recent years. Previous studies have shown that perforated plates have their own ESR and it is a function of geometry and is independent from their materials. In this study the only geometry dependence and physical meaning of ESR were clarified. ESR results were compared with Reference Stress Method (RSM) results for unit-ligaments with various ligament efficiencies. It was revealed that RSM results coincide with ESR. First meaning of ESR is stress ratio between solid plate and perforated plate at the same reference stresses. Second meaning of this ratio is how plasticity properties of equivalent solid plate have to be changed to give the same steady state deformation rate at the same mean boundary stress. Moreover, to clarify stress redistribution control mechanism at different ligament efficiencies, simple models were developed and an estimation method based on simple models was proposed for engineering use.

Resonant frequencies of perforated plates with rectangular slots

2016 ◽  
Vol 232 (7) ◽  
pp. 1247-1254 ◽  
Author(s):  
Oumar R Barry ◽  
Emadeddin Y Tanbour
Keyword(s):  
Elastic Properties ◽  
Material Properties ◽  
Natural Frequencies ◽  
Perforated Plate ◽  
Free Vibrations ◽  
Equivalent Material ◽  
Resonant Frequencies ◽  
Perforated Plates ◽  
Rectangular Slot ◽  
Solid Plate

Most previous work on perforated plates employed elasticity theory to determine equivalent material properties that make the deflection of the solid plate identical to that of the perforated plate. However, it will be inaccurate to utilize the proposed elastic properties to predict the natural frequencies of a perforated plate. In this paper, the free vibrations of perforated plates with rectangular slots and rectangular slot-patterns are examined using theoretical and finite-element methods. The natural frequencies are obtained for various cases of perforations. An explicit expression is obtained for the equivalent elastic properties using the regression analysis method. These effective material properties are used in a solid-plate model to predict the natural frequencies of the corresponding perforated plate. To validate the theoretical analysis, the effective resonant frequencies are compared with the exact natural frequencies of the perforated plates. Parametric studies are conducted to examine the effect of both parallel and perpendicular ligament efficiencies on the resonant frequencies.

scholarly journals Features of subsonic air flow around perforated plates

2020 ◽  
Author(s):  
A.G. Golubev ◽  
E.G. Stolyarova ◽  
M.D. Kalugina
Keyword(s):  
Normal Force ◽  
Air Flow ◽  
Angle Of Attack ◽  
Vertical Plane ◽  
Perforated Plate ◽  
Aerodynamic Characteristics ◽  
Perforated Plates ◽  
Subsonic Speed ◽  
Solid Plate ◽  
Zero Degree

The paper considers the process of flow around a flat plate with rounded front and side edges at various degrees of surface perforation. The flow patterns were studied both near the plate with zero degree of perforation, and at the surface of plates with a perforation degree of more than 20%. The features of air flow directly inside the holes at various values of the angle of attack are considered. Isobars of pressure distribution in the vertical plane of the flow over a solid plate are given. A simulation of the flow around a perforated plate at subsonic speed of the incoming air flow is performed, aerodynamic characteristics are obtained and graphical dependencies of the aerodynamic coefficients of longitudinal and normal force on the angle of attack are presented. Special attention is paid to the comparative analysis of aerodynamic characteristics for solid (with zero degree of perforation) and perforated plates.

On the Determination of Effective Elastic-Plastic Properties for the Equivalent Solid Plate Analysis of Tube Sheets

1974 ◽  
Vol 96 (3) ◽  
pp. 220-227 ◽  
Author(s):  
T. Slot ◽  
T. R. Branca
Keyword(s):  
Numerical Solutions ◽  
Solid Material ◽  
The Finite Element Method ◽  
Plastic Properties ◽  
Perforated Plates ◽  
Elastic Plastic ◽  
Solid Plate ◽  
Plate Analysis ◽  
Metal Properties

Practical procedures are described for the evaluation of effective material properties for use in elastic-plastic analyses of perforated plates involving the equivalent solid plate approach. The finite-element method is used to generate numerical solutions that permit these properties to be determined for a given penetration pattern and given base metal properties. An example is treated for the triangular penetration pattern. The results are illustrative of the anisotropy of the equivalent solid material.

Yield Criterion for Thin Perforated Plates With Square Penetration Pattern

2004 ◽  
Vol 126 (2) ◽  
pp. 169-178
Author(s):  
A. Bhattacharya ◽  
V. Venkat Raj
Keyword(s):  
Finite Element ◽  
Fourth Order ◽  
Yield Criterion ◽  
Pure Shear ◽  
Second Order ◽  
Plane Stress Condition ◽  
Element Analysis ◽  
Perforated Plates ◽  
Order Polynomial ◽  
Solid Plate

Second and fourth order polynomials describing the yield criterion for perforated plates with square penetration pattern were developed following the methodology shown by Hill (1950) and later by Reinhardt (2001) for triangular penetration pattern. The inadequacy of Hill’s (1950) criterion to describe the yield surface of the equivalent solid plate was observed by Reinhardt (2001). Unlike in the case of triangular penetration pattern, the second-order polynomial satisfies the uniqueness of yield stresses after symmetric rotation in the case of square penetration pattern, even though the second order polynomial is incomplete as it cannot satisfy the yield criterion for pure shear. However, the fourth order polynomial is found to satisfy the symmetry and boundary conditions arising from biaxial loadings completely and shows closer agreement with the finite-element results obtained by the authors as compared to the second-order polynomial. Some of the finite-element results were compared with the experimental results of Litewka (1991) and the agreement between them was found to be satisfactory. The effect of out-of-plane stresses have not been considered in the present investigation as these are found to be negligible in case of thin perforated plates, for which plane stress condition was assumed in the finite element analysis.

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.

High Speed Flow through Perforated Plates

1960 ◽  
Vol 64 (590) ◽  
pp. 103-105
Author(s):  
P. G. Morgan
Keyword(s):  
Pressure Drop ◽  
High Speed ◽  
Perforated Plate ◽  
Wire Mesh ◽  
Flow Conditions ◽  
High Speed Flow ◽  
Perforated Plates ◽  
Speed Flow ◽  
Flow Through ◽  
Points Of View

The flow through porous screens has been widely studied from both the theoretical and experimental points of view. The most widely used types of screen are the wire mesh and the perforated plate, and the majority of the literature has been concerned with the former. Several attempts have been made to correlate the parameters governing the flow through such screens, i.e. the pressure drop, the flow conditions and the geometry of the mesh.

scholarly journals THE STUDY OF ACOUSTIC CHARACTERISTICS OF THE PERFORATED AND HOMOGENOUS PLATES WITH SIMILAR GEOMETRICAL DIMENSIONS

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 79-82
Author(s):  
Valery Kirpichnikov ◽  
Lyudmila Drozdova ◽  
Alexei Koscheev ◽  
Ernst Myshinsky
Keyword(s):  
Resonant Frequency ◽  
Acoustic Radiation ◽  
Perforated Plate ◽  
Acoustic Characteristics ◽  
Resonant Frequencies ◽  
Perforated Plates ◽  
Resonance Frequencies ◽  
Flexural Vibrations ◽  
Geometrical Dimensions

The resonance frequencies of the flexural vibrations, input vibration excitability and acoustic radiation of the homogeneous and perforated plates were investigated. It is established that the average reduction range of the lower resonant frequency of flexural vibrations of the tested plates with the holes virtually coincides with the predictive estimate. The levels of the input vibration excitability of the perforated plate at the lower resonant frequencies exceeded the levels at the corresponding frequencies of the homogeneous plates greater than the calculated value. The levels of resonance acoustic radiation of the perforated plate were significantly less than of the homogeneous one.

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