Transient and Residual Stresses in Heat-Treated Plates

1958 ◽  
Vol 25 (4) ◽  
pp. 459-465
Author(s):  
H. G. Landau ◽  
J. H. Weiner
Keyword(s):  
Stress Distribution ◽  
Residual Stresses ◽  
Cooling Rate ◽  
Thermal Stresses ◽  
Heated Plate ◽  
Perfectly Plastic ◽  
Heat Treated ◽  
The Face ◽  
Elastic Perfectly Plastic

Abstract Equations are given for determining transient and residual thermal stresses in a heat-treated plate. The material of the plate is assumed to be elastic, perfectly plastic. The temperature is assumed uniform on any plane parallel to the faces of the plate but can vary arbitrarily in the direction normal to the face and in time. The stress distribution during the unloading period is determined exactly without the simplifying assumption of simultaneous unloading. Application is made to the determination of stresses during cooling of a uniformly heated plate. The stress-distribution sequence and residual stresses are calculated for several values of cooling rate and yield stress.

Effect of Core Plasticity on the Post-Buckling Behavior of Debonded Sandwich Beams

2000 ◽  
Author(s):  
Bhavani V. Sankar ◽  
Manickam Narayanan ◽  
Abhinav Sharma
Keyword(s):  
Plastic Material ◽  
Maximum Load ◽  
Face Sheet ◽  
Compression Tests ◽  
Element Analysis ◽  
The Core ◽  
Perfectly Plastic ◽  
The Face ◽  
Post Buckling ◽  
Elastic Perfectly Plastic

Abstract Nonlinear finite element analysis was used to simulate compression tests on sandwich composites containing debonded face sheets. The core was modeled as an elastic-perfectly-plastic material, and the face-sheet as elastic isotropic. The effects of core plasticity, face-sheet and core thickness, and debond length on the maximum load the beam can carry were studied. The results indicate that the core plasticity is an important factor that determines the maximum load.

scholarly journals Principal Stress Ratio Effect at Residual Stress Determination Utilizing the Variation of Indentation Hardness

Lubricants ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 50
Author(s):  
Per-Lennart Larsson
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Ratio ◽  
Experimental Situation ◽  
Indentation Hardness ◽  
Stress Determination ◽  
Residual Stress Determination ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Elastic Perfectly Plastic

The determination of residual stresses is an important issue when it comes to material failure analysis. The variation of global indentation properties, due to the presence of residual stresses, can serve as a guideline for the size and direction of such stresses. One of these global indentation properties, the material hardness, is unfortunately invariant of residual stresses when metals and alloys are at issue. In this situation, one has to rely on the size of the indentation contact area for residual stress determination. For other materials such as ceramics and polymers, where elastic deformations are of greater importance at indentation, such invariance is no longer present. Here, this variation is investigated based on finite element simulations. The aim is then to determine how the indentation hardness is influenced by the principal residual stress ratio and also discuss if such an influence is sufficient in order to determine the size and direction of such stresses in an experimental situation. It should be emphasized that this work does not suggest a new approach to residual stress determination (by indentation testing) but investigates the applicability of previously derived methods to a situation where the surface stress field is not simplified as equi-biaxial or uniaxial. For simplicity, but not out of necessity, only cone indentation of elastic-perfectly plastic materials is considered.

The Study on the Residual Stresses of Circular Sawblades with Spherical Surface Pressed Many Spots

2010 ◽  
Vol 29-32 ◽  
pp. 1323-1326
Author(s):  
Qiu Yun Mo ◽  
Zhan Kuan Zhang ◽  
Hao Li
Keyword(s):  
Stress Distribution ◽  
Residual Stresses ◽  
Thermal Stresses ◽  
Distribution Curve ◽  
Spherical Surface ◽  
Comprehensive Analysis ◽  
X Ray ◽  
Circular Saws

This paper is a comprehensive analysis about circular saws exerted the inertia stresses, thermal stresses and residual stresses inducted roll and hammer tensioning in working procedures. And analyze the weaknesses and the advantages of two methods of roll tensioning and hammer tensioning. In order to take advantages to compensate the weaknesses to bring forward a new tensioning method compressed many areas i.e. the tensioning spots compressed by using the roll-head whose surface is spherical, cylindrical or cone. The X-ray stress-checking instrument is used to test the residual stresses in the tensioned circular sawblades compressed on many spots. The result explains the stress distribution curve is very ideal and the residual stresses by tensioning almost offset the total inertia and thermal stresses inducted in the work. This explains it is a new circular tensioning method with developing value by compressing many spots. It exists in certain residual stresses on the rim of the sawblade’s central bore, outside and the areas near the slot bore because of the influence of the machine processes.

Residual Stress Relief in the Aluminium Alloy 7075

2017 ◽  
Vol 905 ◽  
pp. 31-39 ◽  
Author(s):  
Jeremy S. Robinson ◽  
Christopher E. Truman ◽  
Thilo Pirling ◽  
Tobias Panzner
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Stress Relief ◽  
Residual Stress Distribution ◽  
Cold Compression ◽  
Heat Treated ◽  
Minimum Residual

The residual stresses in heat treated 7075 aluminium alloy blocks have been characterised using two neutron diffraction strain scanning instruments. The influence of uniaxial cold compression (1-10%) on relieving the residual stress has been determined. Increasing the magnitude of cold compression from 1 to 10% has been shown to have a beneficial effect on the residual stress distribution by reducing the range between the maximum and minimum residual stresses. The effect of over aging 7075 on residual stress has also been characterised using neutron diffraction and this was found to reduce the residual stress by 25-40%. A relationship between {311} peaks widths and amount of cold compression was also observed.

scholarly journals Thermo-Mechanical Modeling of Distortions Promoted during Cooling of Ti-6Al-4V Part Produced by Superplastic Forming

2016 ◽  
Vol 838-839 ◽  
pp. 196-201
Author(s):  
Maxime Rollin ◽  
Vincent Velay ◽  
Luc Penazzi ◽  
Thomas Pottier ◽  
Thierry Sentenac ◽  
...  
Keyword(s):  
Finite Element ◽  
Thermal Stresses ◽  
Superplastic Forming ◽  
Model Material ◽  
Material Behavior ◽  
Mechanical Modeling ◽  
Temperature Dependent ◽  
Finite Element Software ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

In AIRBUS, most of the complex shaped titanium fairing parts of pylon and air inlets are produced by superplastic forming (SPF). These parts are cooled down after forming to ease their extraction and increase the production rate, but AIRBUS wastes a lot of time to go back over the geometric defects generated by the cooling step. This paper investigates the simulations of the SPF, cooling and clipping operations of a part on Abaqus® Finite element software. The different steps of the global process impact the final distortions. SPF impacts the thickness and the microstructure/behavior of material, cooling impacts also the microstructure/behavior of material and promotes distortions through thermal stresses and finally, clipping relaxes the residual stresses of the cut part. An elastic-viscoplastic power law is used to model material behavior during SPF and a temperature dependent elastic perfectly plastic model for the cooling and clipping operations.

Elastic, Plastic Stresses in Free Plate With Periodically Varying Surface Temperature

1958 ◽  
Vol 25 (4) ◽  
pp. 603-606
Author(s):  
Halil Yüksel
Keyword(s):  
Steady State ◽  
Surface Temperature ◽  
Constant Temperature ◽  
Thermal Stresses ◽  
Plastic Material ◽  
The Other ◽  
Perfectly Plastic ◽  
Temperature Oscillations ◽  
Steady State Temperature ◽  
Elastic Perfectly Plastic

Abstract The paper is concerned with a free plate that consists of an elastic, perfectly plastic material and is subjected to a harmonically varying temperature at one face, while the other face is kept at a constant temperature and the edge is perfectly insulated. The thermal stresses associated with the steady-state temperature oscillations are analyzed, and the development of plastic regions is discussed.

Computerized Relaxation Applied to the Plane-Strain Indenter

1969 ◽  
Vol 91 (4) ◽  
pp. 816-821
Author(s):  
J. W. Wesner ◽  
A. S. Weinstein
Keyword(s):  
Stress Distribution ◽  
Plane Strain ◽  
Slip Line ◽  
Relaxation Method ◽  
Strip Thickness ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Distribution Problems ◽  
Plastic Stress

A computer adaptation of Southwell’s Relaxation Method was developed for the solution of elastic-perfectly plastic stress distribution problems. This method was employed to study some aspects of the problem of the plane-strain indenter. For two ratios of strip thickness to indenter width, the load for, and location of, initial yielding and the load for the onset of indentation were found. The results are compared with slip-line solutions.

scholarly journals Analysis of Quenching and Stretching Processes of Aluminum Alloy Thick Plates

2014 ◽  
Vol 996 ◽  
pp. 532-537
Author(s):  
Hai Gong ◽  
Yun Xin Wu ◽  
Zhao Peng Yang ◽  
Kai Liao
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Thick Plates ◽  
7050 Aluminum Alloy ◽  
Heat Treated ◽  
Strong Inhomogeneity

7050 aluminum alloy thick plates are usually heat treated and then aged to improve mechanical properties; however, residual stresses in the plates are developed during quenching. In this study, the influences of non-uniform factors on residual stresses in aluminum alloy thick plates during the quenching and stretching processes are studied. The results show strong inhomogeneity of the residual stress distribution in the plates, and the length of influenced area of the stretched plate is discussed.

scholarly journals Effect of the heat treatment mode of high chrome iron rolling mills on chrome redistribution in the stress field

2021 ◽  
pp. 113
Author(s):  
Olena Popova ◽  
Nataliia Lalazarova ◽  
Оlga Afanasieva
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Cooling Rate ◽  
Uniform Distribution ◽  
Temperature Difference ◽  
Thermal Stresses ◽  
Stress Gradient ◽  
Working Layer ◽  
Heating And Cooling ◽  
Uneven Heating

Heat treatment is an important stage in the technology of rolling rolls, due to the fact that the thermal stresses that occur during rapid or uneven heating summing up with the rather high residual stresses after casting, create a risk of cracking. Goal. The aim is improving the quality of rolling rolls by varying the modes of heat treatment. Therefore, it is important to assess the level of thermal stress. Method. Evaluation of thermal stresses arising in heating and cooling in the heat treatment process that summing up to the relatively high residual stresses after casting, creates the risk of fractures. The profile of the distribution of chromium in the cross section of the working layer at each time under the action of the stress gradient that occurs during heat treatment of the roll is obtained by calculation. Results To ensure a minimum temperature difference between the surface and the core, it is necessary to reduce the heating and cooling rate, as well as increase the duration of exposure at a given temperature. Reducing the cooling rate from 17 to 3.7°C/h decreases the temperature difference at the surface and in the center of the roll and the intensity of thermal stresses from 29 to 7 MPa. It is established that the rate of heating and cooling should not exceed 10– 15° C/h, and exposure to annealing should be at least 5–7 hours. Scientific novelty. The modes of heat treatment of rolling rolls with a high-chromium cast iron working layer are designed by estimating the level of thermal stresses. The profile of distribution of chromium after various modes of heat treatment is calculated analytically and its mode at which the most uniform distribution of chromium on section of a working layer remains is offered. Practical significance. The developed technique allows to calculate analytically the profile of distribution of chromium after various modes of heat treatment and to choose such a mode at which the most uniform distribution of chromium remains on the section of a working layer.

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