Plane strain bending with work hardening

1966 ◽  
Vol 1 (3) ◽  
pp. 196-203 ◽  
Author(s):  
A. A. Denton
Keyword(s):  
Plane Strain ◽  
Work Hardening ◽  
Copper Plate ◽  
Stress And Strain ◽  
Bending Stress ◽  
Current Yield ◽  
Geometrical Method ◽  
Hardening Material ◽  
Strain Paths

Possible approaches to an analytical solution to the plane strain bending of a work hardening material are discussed. It is shown that the bending stress (δ x) and strain ε x) can be expressed independently in terms of the current yield stress and increment, but that further progress to the function δ x = ε x) is impeded by the implicity of the separate functions for δ x andε x. The solution is completed by a numerical method and used to determine the stress and strain paths in a wide copper plate subjected to bending. A geometrical method is also shown to exist, but is discarded because of the necessity for an iterative determination of the stress and strain increments.

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.

Evaluation of the Work-Hardening of Brass Sheets Following Strain Path Changes

2010 ◽  
Vol 89-91 ◽  
pp. 353-358
Author(s):  
Wellington Lopes ◽  
Elaine Carballo Siqueira Corrêa ◽  
Haroldo Béria Campos ◽  
Maria Teresa Paulino Aguilar ◽  
Paulo Roberto Cetlin
Keyword(s):  
Simple Shear ◽  
Work Hardening ◽  
Tensile Testing ◽  
Strain Path ◽  
Adequate Description ◽  
Simple Tension ◽  
Strain Paths ◽  
Strain Path Changes ◽  
Machining Operations

The strain paths followed by metals during sheet forming can be quite complex, especially when successive forming steps are involved. The work hardening of metals associated with these strain paths differs from that caused only by monotonic straining, such as simple tension or compression. It is important to have an adequate description of the work hardening of the material under processing, especially when numerical simulations of the forming are used. The experimental evaluation of the effect of strain path changes on the material work hardening is usually performed through tensile testing following the strain path changes. This technique, however, demands complex machining operations of the formed sheets and the imposed strain is severely limited by impending necking. The present paper utilizes simple shear as a tool for the determination of the work hardening of CuZn34 brass sheets following various strain path changes associated with combinations of different modes of deformation such as rolling, tension, cyclic and forward shears. The results indicate that the cyclic shearing delays the occurrence of plastic instabilities for brass previously tensioned, occurring the opposite for final monotonic shearing. These phenomena were correlated with the probable microstructural evolution of the CuZn34 brass.

Elastoplastic Stress and Strain Distribution in a Finite Plate With a Circular Hole Subjected to Unidimensional Load

1963 ◽  
Vol 30 (1) ◽  
pp. 115-121 ◽  
Author(s):  
A. J. Durelli ◽  
C. A. Sciammarella
Keyword(s):  
Experimental Determination ◽  
Circular Hole ◽  
Strain Distribution ◽  
Stress And Strain ◽  
Hardening Material ◽  
Finite Plate ◽  
Elastoplastic Stress ◽  
Moire Method ◽  
Stress And Strain Distribution

This paper deals with the experimental determination of the elastoplastic stress and strain distribution around an empty circular hole in a finite aluminum plate subjected to a unidimensional load as the deformation increases from the elastic far into the plastic field. The strains were measured using the moire method. The stresses were computed by means of the Prandtl-Reuss stress-strain relationships presented in a convenient form for the case of a strain-hardening material.

Effects of root radius, stress, crack growth and rate on fracture instability

1965 ◽  
Vol 285 (1400) ◽  
pp. 58-72 ◽  
Keyword(s):  
Plane Strain ◽  
Local Stress ◽  
Small Region ◽  
Constant Load ◽  
Stress And Strain ◽  
Root Radius ◽  
Hardening Material ◽  
History Of ◽  
Fracture Instability ◽  
Increasing Load

Of various criteria for fracture at the root of a notch, the energy, local stress, and displacement criteria have limited validity. More appropriate is the history of both stress and strain over a small region ahead of the crack, as required for fracture by the coalescence of holes. Expressions are given for crack initiation, growth, and subsequent instability in anti-plane strain of a non-hardening material. Instability is shown to depend primarily on those strain increments arising from crack grow that constant load rather than on those from increasing load at constant crack length. Thus final instability conditions are similar for single and double-ended cracks, round notches, and cracks cut under constant load. Round notches may give instability, restabilization, and final instability. The growth and coalescence of holes in front of a crack in a linearly viscous material is studied for both tensile and anti-plane-strain cracks. The absence of residual strain eliminates instability, but the crack continually accelerates.

Consideration of Environmentally Assisted Fatigue in Austenitic Stainless Steel: Calculation and Practical Application

2012 ◽  
Author(s):  
Sven H. Reese ◽  
Johannes Seichter ◽  
Dietmar Klucke
Keyword(s):  
Primary Circuit ◽  
Stress And Strain ◽  
Loading Conditions ◽  
Practical Application ◽  
Circuit Component ◽  
Detailed Assessment ◽  
The Mean ◽  
Fatigue Evaluation ◽  
Assessment Procedures

The influence of LWR coolant environment to the lifetime of materials has been discussed recent years. Nowadays the consideration of environmentally assisted fatigue is under consideration in Codes and Standards like ASME and the German KTA Rules (e.g. Standard No. 3201.2 and Standard No. 3201.4) by means of so called attention thresholds. Basic calculation procedures in terms of quantifying the influence of LWR coolant environment by the Fen correction factor were proposed by Higuchi and others and are given in NUREG/CR-6909. This paper deals with the application of the proposed assessment procedures of ANL and the application to plant conditions. Therefore conservative assessment procedures are introduced without assuming the knowledge of detailed stress and strain calculations or temperature transients. Additionally, detailed assessment procedures based on Finite-Element calculations, respecting in-service temperature measurements including thermal reference transients and complex operational loading conditions are carried out. Fatigue evaluation of a PWR primary circuit component is used in order to evaluate the influence of plant like conditions numerically. Conclusions regarding the practical application are drawn by means of comparing the ANL approach considering laboratory conditions, conservative assessment procedures for the determination of cumulative fatigue usage factors of plant components and detailed assessment procedures. Plant like loading conditions, complex component geometries, loading scenarios and reference temperature transients shall be taken into account. Practical issues like the determination of the mean temperature or the strain rate have to be considered adequately.

DETERMINATION OF CORROSION INFLUENCE ON FUEL METAL, OBTAINED FROM SECONDARY POLYMER RAW MATERIALS

2021 ◽  
pp. 48-56
Author(s):  
K. Сhevchenko ◽  
A. Grigorov ◽  
I. Sinkevich
Keyword(s):  
Raw Materials ◽  
Petroleum Products ◽  
Copper Plate ◽  
Water Soluble ◽  
Synthetic Fuels ◽  
Laboratory Setup ◽  
Corrosive Effect ◽  
Preliminary Preparation ◽  
Sulfur Containing

The article proposes to determine the corrosion effect on fuel metals under dynamic conditions, when washing the prepared copper plate of a certain size, a significant amount of fuel at a certain speed and temperature of the study. This approach will significantly reduce the duration of the study (up to 100 minutes) and is closer to the real conditions of contact of the fuel with a metal surface, in comparison with the standardized method, which is widely used today. Using the proposed laboratory setup, the study was subjected to fuel (200–360 °C), which was obtained by thermal destruction of secondary polymer raw materials, in particular polypropylene. The obtained results showed that the investigated fuel, despite the temperature, the amount of circulating fuel and its water content, does not have a corrosive effect on the copper plate, which can be explained by the absence of corrosive substances in the fuel: water-soluble mineral acids and alkalis, active sulfur compounds and organic acids. However, it should be kept in mind that in polyolefin raw materials, in the form of contamination, there may be products made of other materials, such as rubber and polyvinyl chloride. This can happen when the sorting technology is violated or during the preliminary preparation of raw materials and, in turn, will contribute to the increase in sulfur-containing and chlorine-containing compounds in the fuel, which are characterized by high corrosion activity and should be necessarily removed from the fuel. Note that the fuel obtained from secondary polymer raw materials, in the absence of sulfur-containing and chlorine-containing compounds, is quite promising for the creation on its basis of modern synthetic fuels, analogues of classic petroleum products.

Research of stamping of unequal channel bars. Part 4. Deformed state of the workpiece when extruding channels. 2. Deformations under the punch end

2021 ◽  
pp. 53-57
Author(s):  
A.L. Vorontsov
Keyword(s):  
Plastic Deformation ◽  
Plane Strain ◽  
Deformation Zone ◽  
Plastic Deformation Zone ◽  
Die Forging ◽  
Deformed State

Determination of the deformed state of the workpiece at free extrusion of channels is considered. Formulas are obtained for determining the accumulated deformations at a given point of the plastic deformation zone and extruded walls of the product for any punch working stroke. Keywords: die forging, extrusion, misalignment, punch, matrix, plane strain, accumulated deformations, hardening. [email protected]

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