Refined Theory for Bending and Torsion of Perforated Plates

1986 ◽  
Vol 108 (4) ◽  
pp. 423-429 ◽  
Author(s):  
P. Meijers
Keyword(s):  
Asymptotic Solution ◽  
Thick Plate ◽  
Plate Thickness ◽  
Perforated Plate ◽  
Numerical Data ◽  
Refined Theory ◽  
Infinite Strip ◽  
Perforated Plates ◽  
Hole Radius ◽  
Doubly Periodic Solution

An asymptotic solution is given for the effective elastic constants and the stresses in a perforated plate which is loaded in bending and torsion. In this solution terms 0(h/R)2 are neglected with respect to unity; h being the plate thickness and R the hole radius. In addition to the doubly periodic solution of the classical plate problem another bi-potential problem and two auxiliary problems, viz., a plane strain and a torsion problem for a half-infinite strip, have to be solved. The asymptotic solution together with an approximate solution for an infinitely thick plate permits us often to construct a solution which covers the entire range of h/R; viz., 0≤h/R<∞. In a number of cases accurate interpolation requires additional finite-element calculations. The numerical data presented here apply to a square or an equilateral triangular hole pattern.

Comparison of Limit Load Solutions with Results of Collapse Tests of Perforated Plates with a Triangular Penetration Pattern

2002 ◽  
Author(s):  
D. P. Jones ◽  
J. L. Gordon
Keyword(s):  
Plate Thickness ◽  
Perforated Plate ◽  
Limit Load ◽  
Small Strain ◽  
Transverse Load ◽  
Strength Parameter ◽  
Plastic Collapse ◽  
Perforated Plates ◽  
Small Deflection ◽  
Deformation Patterns

Limit load solutions obtained by elastic-perfectly plastic finite element analysis (EPP-FEA) are compared to results of tests of low-alloy steel perforated plate geometries loaded to full plastic collapse. Results are given for two plastic-collapse tests of flat circular disks with circular penetrations arranged in a triangular pattern and drilled normal to the surface of the plate. The ligament efficiency (minimum distance between holes divided by the distance between the centers of the holes) of the pattern is 0.32 and the plate thickness is 2.39 inches (60.7 mm). The tests were designed so that a transverse load generated plastic collapse in the outer row of penetrations due to a combination of transverse shear and in-plane bending. Limit-load solutions were obtained using EPP-FEA with small-strain, small-deflection linear geometry assumptions. Two FEA models are used: one where the perforated region is modeled using an equivalent solid plate (EQS) representation and another where each hole is explicitly modeled by FEA. The results presented in this paper demonstrate that the deformation patterns produced by the EPP-FEA solutions match exactly with the deformation patterns produced by the test. The EQS-EPP FEA solution is about 15% lower than the explicit-hole EPP-FEA solution. Using one-third the actual ultimate strength of the material as the strength parameter in the limit load calculation produces a calculated limit load that is greater than a factor of three less than the mean measured plastic-collapse load obtained in the tests. This paper adds to the qualification of the use of limit-load solutions obtained using small-strain, small deflection EPP-FEA programs for the calculation of the limit load for perforated plates.

scholarly journals Research of stress distribution in the cross-section of a bimetallic perforated plate perpendicularly loaded with concentrated force

2020 ◽  
Vol 15 (55) ◽  
pp. 241-257
Author(s):  
Mateusz Konieczny ◽  
Henryk Achtelik ◽  
Grzegorz Gasiak
Keyword(s):  
Stress Distribution ◽  
Plate Thickness ◽  
Perforated Plate ◽  
Von Mises Stress ◽  
Engineering Structures ◽  
Concentrated Force ◽  
Perforated Plates ◽  
Titanium Layer ◽  
The Difference ◽  
Von Mises

The paper presents the stress distribution along the plate thickness in a bimetallic steel – titanium circular, axially symmetrical perforated plate produced in the technological process of explosion welding. The steel layer is the layer that transfers the load in the plate, while the titanium layer is used to improve the properties of the plate, e.g. corrosion resistance, thermal transmittance, etc. in the plate. Two cases of fastening were considered, i.e. a freely supported and fixed plate. Such plates are used in various engineering structures, e.g. simply supported plates can be used in loose material screens, while plates are fixed in heat exchangers. The load was assumed as a concentrated force applied perpendicularly to the plate surface. The results obtained numerically using the finite element method were compared with the results calculated according to the analytical equations. It has been shown that the difference in the results of equivalent von Mises stress calculations does not exceed 13%. The research results presented in the paper can be used by engineers to design bimetallic perforated plates perpendicularly loaded to their surface.

Stresses in an Infinite Strip Containing a Semi-Infinite Crack

1966 ◽  
Vol 33 (2) ◽  
pp. 356-362 ◽  
Author(s):  
W. G. Knauss
Keyword(s):  
Fracture Mechanics ◽  
Stress Field ◽  
Asymptotic Solution ◽  
Asymptotic Expansions ◽  
Region Of Interest ◽  
Graphical Form ◽  
Finite Width ◽  
Infinite Strip ◽  
Arbitrary Length ◽  
Laboratory Investigations

Stresses in an infinitely long strip of finite width containing a straight semi-infinite crack have been calculated for the case that the clamped boundaries are displaced normal to the crack. The solution is obtained by the Wiener-Hopf technique. The stresses are given in the form of asymptotic expansions in the immediate crack tip vicinity and for a larger region of interest in graphical form. The effect of prescribing displacements on the boundary close to a crack instead of stresses far away is discussed briefly. Together with an asymptotic solution for a small crack, the result is used to estimate the stress field around a crack of arbitrary length in an infinite strip. The usefulness of this crack geometry in laboratory investigations of fracture mechanics is pointed out.

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.

The Aerodynamic Drag of Perforated Plates at Zero Incidence

1958 ◽  
Vol 62 (568) ◽  
pp. 301-303 ◽  
Author(s):  
P. Minton ◽  
J. R. D. Francis
Keyword(s):  
Pipe Flow ◽  
Aerodynamic Drag ◽  
Perforated Plate ◽  
Perforated Plates ◽  
Drag Forces ◽  
Flow Experiments

Perforated Plates have been used at large angles of incidence to produce drag forces and evidence on their properties has been published by de Bray. Less appears to be known about the drag forces on such surfaces at zero incidence, although they are usually considered to be aerodynamically rough. This has been confirmed by Ambrose, who carried out pipe flow experiments using perforated liners which fitted tightly in the bore of a pipe. Perforated plates used in this way do not allow flow completely through them and give “pitted” surfaces. If a perforated plate is mounted so that it is possible for cross flows to occur between the main flows on both sides of the plate the drag forces on it may be affected, and in this case the perforations will be referred to as “holes.”

Improvement of Forced Convection Cooling Due to the Attachment of Heat Sources to a Conducting Thick Plate

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Mohammad Reza Hajmohammadi ◽  
Antonio Campo ◽  
S. Salman Nourazar ◽  
Amir Masood Ostad
Keyword(s):  
Forced Convection ◽  
Thick Plate ◽  
Plate Thickness ◽  
Heat Current ◽  
Heat Sources ◽  
Excess Temperature ◽  
Optimal Thickness ◽  
Numerical Work ◽  
Flowing Fluid ◽  
Convection Cooling

It is proposed that a conductive thick plate is placed between a heat source and a cold flowing fluid to improve the forced convection cooling performance. Detailed numerical work is carried out to determine the optimal thickness of the conductive thick plate which minimizes the peak temperature. It is shown that the thick plate significantly reduces the excess temperature of heat sources, by way of conducting the heat current in an optimal manner. It is shown that the reduction in the excess temperature of heat sources depends upon the Reynolds number of the fluid flow and the material thermal conductivity. Correlations for the optimum plate thickness and reduction in excess temperature of heat sources are presented, which could be useful for the practitioners.

Vibration Characteristics of a Perforated Plate Immersed in Fluid

2012 ◽  
Author(s):  
Tomohiro Ito ◽  
Atsuhiko Shintani ◽  
Chihiro Nakagawa
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Damping Ratio ◽  
Thermal Power ◽  
Perforated Plate ◽  
Vibration Characteristics ◽  
Chemical Plants ◽  
Perforated Plates ◽  
Stiffness Reduction ◽  
Test Models

Perforated plates are used in many mechanical structures in thermal power plants, nuclear power plants, or chemical plants etc. Cylindrical structures made by the perforated plates are also found in many places. However, vibration characteristics of the structures made by perforated plates are not fully clarified, especially for the structures immersed in liquid. The stiffness of the structures becomes smaller than that of ones made by simple plates with no holes, while the mass of the structures also becomes smaller. According to the balance between the stiffness reduction and mass reduction, natural frequencies will be decided. Moreover, added mass and added damping effects are very large in liquid, and are thought to largely change due to holes. In this study, as a fundamental step, a perforated plate is treated. The vibration characteristics such as natural frequency and damping ratio are studied for various hole numbers or various opening ratios by both numerical simulations and simple test models. Vibration tests are conducted in liquid as well as in air.

scholarly journals An Experimentally Validated Numerical Modeling Technique for Perforated Plate Heat Exchangers

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
M. J. White ◽  
G. F. Nellis ◽  
S. A. Klein ◽  
W. Zhu ◽  
Y. Gianchandani
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Model ◽  
Heat Exchangers ◽  
Perforated Plate ◽  
Plate Heat Exchanger ◽  
Internal Temperature ◽  
Perforated Plates ◽  
Axial Conduction ◽  
Plate Heat

Cryogenic and high-temperature systems often require compact heat exchangers with a high resistance to axial conduction in order to control the heat transfer induced by axial temperature differences. One attractive design for such applications is a perforated plate heat exchanger that utilizes high conductivity perforated plates to provide the stream-to-stream heat transfer and low conductivity spacers to prevent axial conduction between the perforated plates. This paper presents a numerical model of a perforated plate heat exchanger that accounts for axial conduction, external parasitic heat loads, variable fluid and material properties, and conduction to and from the ends of the heat exchanger. The numerical model is validated by experimentally testing several perforated plate heat exchangers that are fabricated using microelectromechanical systems based manufacturing methods. This type of heat exchanger was investigated for potential use in a cryosurgical probe. One of these heat exchangers included perforated plates with integrated platinum resistance thermometers. These plates provided in situ measurements of the internal temperature distribution in addition to the temperature, pressure, and flow rate measured at the inlet and exit ports of the device. The platinum wires were deposited between the fluid passages on the perforated plate and are used to measure the temperature at the interface between the wall material and the flowing fluid. The experimental testing demonstrates the ability of the numerical model to accurately predict both the overall performance and the internal temperature distribution of perforated plate heat exchangers over a range of geometry and operating conditions. The parameters that were varied include the axial length, temperature range, mass flow rate, and working fluid.

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