Barreling of Solid Cylinders Under Axial Compression

1985 ◽  
Vol 107 (2) ◽  
pp. 138-144 ◽  
Author(s):  
J. K. Banerjee
Keyword(s):  
Compressive Stress ◽  
Dry Friction ◽  
Strain Curve ◽  
Motor Oil ◽  
Compression Tests ◽  
Stress Strain Curve ◽  
Solid Aluminum ◽  
Aspect Ratios ◽  
Wide Range ◽  
Axial Compressive Stress

Axisymmetric compression tests of solid aluminum cylinders, over a wide range of “aspect ratios” (length/diameter) and both under dry as well as lubricated conditions, suggest that the resulting curvature of the “barrel” formed fits closely a circular arc and its radius follows a power law with the true axial compressive stress. The true compressive stress-strain curve, extrapolated from the experimental data in each test, shows that within the variety of lubricants used the Specific Forming Energy is minimum with teflon sheets as dry lubricant, and increases successively with silicon spray, motor oil, and dry friction.

Effects of Solid Lubricants During Compression Tests

2005 ◽  
Author(s):  
Jayanta Banerjee
Keyword(s):  
Dry Friction ◽  
Solid Lubricant ◽  
Strain Curve ◽  
Solid Lubricants ◽  
Work Piece ◽  
Motor Oil ◽  
Brand Name ◽  
Compression Tests ◽  
Liquid Lubricant ◽  
Element Simulation

During compression of a work-piece between dies or platens, such as in forging, coining and up-setting processes, any impact splashes out the liquid lubricant. Hence a solid lubricant is more effective. In the current study a PTFE, commonly known by the brand name Teflon, and a silicon spray were compared with a motor oil and dry friction (no lubricant). The experimental results were then compared with a finite element simulation model. Both the analyses show that the area under the true stress-strain curve is a minimum in the case of PTFE as a solid lubricant, and increases with silicon spray as the next, and then the motor oil, and finally the dry friction. This area gives the “Specific Forming Energy” for bulk plastic deformation, implying that the frictional losses are the least for PTFE as a lubricant, and increase with spray lubrication of silicon, followed by motor oil and dry friction. The experiments also show that barreling of the cylindrical surface of the work-piece is least for PTFE, and increases exactly in the same order: silicon spray, motor oil and dry friction.

Use of Chip Tension to Obtain a Stress-Strain Curve From Metal Cutting Tests

1963 ◽  
Vol 85 (4) ◽  
pp. 351-355 ◽  
Author(s):  
I. Finnie ◽  
J. Wolak
Keyword(s):  
Metal Cutting ◽  
Strain Curve ◽  
Commercial Purity ◽  
Compression Tests ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Wide Range ◽  
Shear Strains ◽  
The Difference ◽  
Commercial Purity Aluminum

By pulling the chip at various angles during metal cutting, it has been possible to greatly decrease the shear strains and thus to obtain a wide range of shear strains with a single tool. Using this technique, stress-strain curves for commercial purity aluminum have been obtained at −320 deg F (78 deg K) and 68 deg F (293 deg K). These results lie above those obtained from compression tests on the same material and the difference is ascribed largely to strain rate. Limits are imposed on the chip-pulling technique by an instability which appears when the direction of pulling makes too great an angle with the tool face and by fracture.

Out-of-plane behavior of confined masonry walls with aspect ratios greater than one

2021 ◽  
Vol 48 (1) ◽  
pp. 89-97
Author(s):  
Jorge Varela-Rivera ◽  
Joel Moreno-Herrera ◽  
Luis Fernandez-Baqueiro ◽  
Juan Cacep-Rodriguez ◽  
Cesar Freyre-Pinto
Keyword(s):  
Experimental Study ◽  
Aspect Ratio ◽  
Compressive Stress ◽  
Masonry Walls ◽  
Confined Masonry ◽  
Aspect Ratios ◽  
Out Of Plane ◽  
Axial Compressive Stress ◽  
Compressive Strut ◽  
Failure Line

An experimental study on the out-of-plane behavior of confined masonry walls is presented. Four confined walls with aspect ratios greater than one were tested in the laboratory. Walls were subjected to combined axial and out-of-plane uniform loads. The variables studied were the aspect ratio and the axial compressive stress of walls. It was observed that the out-of-plane strength of walls increased as the aspect ratio or the axial compressive stress increased. Failure of walls was associated with crushing of masonry. Analytical out-of-plane strength of walls was determined using the yielding line, failure line, modified yielding line, compressive strut and bidirectional strut methods. It was concluded that the experimental out-of-plane strength of walls was best predicted with the bidirectional strut method.

A General Autofrettage Model of a Thick-Walled Cylinder Based on Tensile-Compressive Stress-Strain Curve of a Material

2005 ◽  
Vol 40 (6) ◽  
pp. 599-607 ◽  
Author(s):  
X. P Huang
Keyword(s):  
Strain Hardening ◽  
Compressive Stress ◽  
Bauschinger Effect ◽  
Strain Curve ◽  
Accurate Prediction ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Perfectly Plastic ◽  
Hardening Models ◽  
Elastic Perfectly Plastic

The basic autofrettage theory assumes elastic-perfectly plastic behaviour. Because of the Bauschinger effect and strain-hardening, most materials do not display elastic-perfectly plastic properties and consequently various autofrettage models are based on different simplified material strain-hardening models, which assume linear strain-hardening or power strain-hardening or a combination of these strain-hardening models. This approach gives a more accurate prediction than the elastic-perfectly plastic model and is suitable for different strain-hardening materials. In this paper, a general autofrettage model that incorporates the material strain-hardening relationship and the Bauschinger effect, based upon the actual tensile-compressive stress-strain curve of a material is proposed. The model incorporates the von Mises yield criterion, an incompressible material, and the plane strain condition. Analytic expressions for the residual stress distribution have been derived. Experimental results show that the present model has a stronger curve-fitting ability and gives a more accurate prediction. Several other models are shown to be special cases of the general model presented in this paper. The parameters needed in the model are determined by fitting the actual tensile-compressive curve of the material, and the maximum strain of this curve should closely represent the maximum equivalent strain at the inner surface of the cylinder under maximum autofrettage pressure.

Hot Deformation Behavior of Q235 Steel during Isothermal Compression at Elevated Temperature

2015 ◽  
Vol 1088 ◽  
pp. 186-190 ◽  
Author(s):  
Ben Yang ◽  
Zhou Zheng ◽  
Li Xin Wang ◽  
Yong Gang Wu
Keyword(s):  
Constitutive Relation ◽  
True Strain ◽  
Strain Curve ◽  
Strain Rates ◽  
Compression Tests ◽  
Q235 Steel ◽  
Wide Range ◽  
Allowable Range ◽  
Experimental Values ◽  
Jc Model

The isothermal hot compression tests of Q235 steel over a wide range of temperatures (1023-1123 K), strain (0.7) and strain rates (1、5、10 s−1) were performed on Gleeble-1500 system. The results show that when the deformation temperature is constant, as the strain rate increases, the flow stress also increases; Use the JC model to establish constitutive relation equation with true stress-true strain curve. And compare the prediction value of the constitutive relation equation with the experimental values, the relative error between the two is within the allowable range, indicating that the JC model constitutive relation equation applicable for the thermal deformation of Q235 steel.

Fatigue in Rubber. Part II

1939 ◽  
Vol 12 (2) ◽  
pp. 332-343 ◽  
Author(s):  
W. J. S. Naunton ◽  
J. R. S. Waring
Keyword(s):  
Carbon Black ◽  
Internal Friction ◽  
High Frequency ◽  
Strain Curve ◽  
Power Input ◽  
Viscous Resistance ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Wide Range ◽  
Rubber Part

Abstract 1. An apparatus is described for measuring the modulus and resilience of rubber over a wide range of frequencies. 2. These measurements can be made at any point in the stress-strain curve of the sample. 3. By increasing the power input, the same apparatus can be used to induce high frequency fatigue in the sample. 4. The earlier work with the torsion head apparatus has been confirmed, namely, that internal friction is greatest near zero strain. 5. High frequency resilience is more independent of degree of vulcanization than tripsometer resilience. 6. Modulus tends to increase with frequency. The effect is least with a rubber gum stock and is greater with compounds containing gas black. 7. Resilience decreases with frequency both in gum and gas black compounds. The decrease is more rapid in the gum compounds. 8. Viscous resistance decreases with frequency and becomes constant at higher frequencies. 9. The modulus of both rubber and Neoprene carbon black compounds decreases with fatigue. 10. The change in modulus with frequency in fatigued stocks is exactly analogous to the change before fatigue in rubber, but there is a slight divergence in the case of Neoprene.

Effect of Uniaxial Compressive Stress during Formation of Porous Aluminum by Mechanochemical Reaction on its Mechanical Properties

2014 ◽  
Vol 922 ◽  
pp. 632-637
Author(s):  
K. Sawamoto ◽  
Noboru Nakayama
Keyword(s):  
Mechanical Properties ◽  
Compressive Stress ◽  
Pure Water ◽  
Mechanochemical Reaction ◽  
Compression Tests ◽  
Porous Aluminum ◽  
Wide Range ◽  
Powder Particles ◽  
Al Powder ◽  
The Individual

Porous Al is a lightweight material with excellent heat insulation and sound absorption properties and is expected to be used in a wide range of applications. A method based on mechanochemical reactions has been developed as an environmentally friendly approach to porous Al production. Pure Al powder reacts with pure water to form a coating layer of Al (OH)3 on the surface of the powder particles. Adjacent particles then bind together by adhesion of their coating layers. Since a large number of voids remain between the individual particles, the compact is classified as porous Al. In the present study, a mixture of pure Al powder and pure water was subjected to uniaxial compressive stresses ranging from 0 to 100 MPa to form porous Al. The mechanical properties of the resulting compact were evaluated in terms of the amount of H2 produced, the density, the Al (OH)3 texture, the amount of Al (OH)3 formed, and the results of subsequent compression tests. The density of the porous Al was found to increase with increasing compressive stress during formation. The largest amounts of H2 (800 ml) were produced under a compressive stress of 10 MPa. As the compressive stress was increased, the total amount of generated Al (OH)3 increased, was approximately constant from 30 to 50 MPa, and then decreased. The initial maximum stress, the plateau stress, and the absorbed energy increased with increasing compressive stress and were 100 MPa, 17.5 MPa, and 10.1 MJ/m3, respectively, for a compressive stress of 100 MPa.

scholarly journals A Stress-Strain Model for Brick Prism under Uniaxial Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Yongjei Lee ◽  
Yong-Ha Hwang
Keyword(s):  
Strain Curve ◽  
Peak Stress ◽  
Test Results ◽  
Compression Tests ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Proposed Model ◽  
Relationship Model ◽  
Strain Relationship ◽  
Strain Model

This study proposes a simple and rational stress-strain relationship model applicable to brick masonry under compression. The brick prism compression tests were conducted with different mortar strengths and with constant brick strength. From the observation of the test results, shape of the stress-strain curve is assumed to be parabola. In developing the stress-strain model, the modulus of elasticity, the strain at peak stress, and the strain at 50% of the peak stress on the descending branch were formulated from regression analysis using test data. Numerical and statistical analyses were then performed to derive equations for the key parameter to determine the slopes at the ascending and descending branches of the stress-strain curve shape. The reliability of the proposed model was examined by comparisons with actual stress-strain curves obtained from the tests and the existing model. The proposed model in this study turned out to be more accurate and easier to handle than previous models so that it is expected to contribute towards the mathematical simplicity of analytical modeling.

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