An Experimental Investigation of the Yield Loci of 1100-0 Aluminum, 70:30 Brass, and an Overaged 2024 Aluminum Alloy After Various Prestrains

1986 ◽  
Vol 108 (4) ◽  
pp. 313-320 ◽  
Author(s):  
D. E. Helling ◽  
A. K. Miller ◽  
M. G. Stout
Keyword(s):  
Aluminum Alloy ◽  
Small Strain ◽  
Yield Locus ◽  
Material Behavior ◽  
Shear Stresses ◽  
2024 Aluminum Alloy ◽  
Yield Loci ◽  
Aluminum Alloy 2024 ◽  
Von Mises ◽  
Normal And Shear Stresses

The multiaxial yield behaviors of 1100-0 aluminum, 70:30 brass, and an overaged 2024 aluminum alloy (2024-T7) have been investigated for a variety of prestress histories involving combinations of normal and shear stresses. Von Mises effective prestrains were in the range of 1.2–32%. Prestress paths were chosen in order to investigate the roles of prestress and prestrain direction on the nature of small-strain offset (ε = 5 × 10−6) yield loci. Particular attention was paid to the directionality, i.e., translation and distortion, of the yield locus. A key result, which was observed in all three materials, was that the final direction of the prestrain path strongly influences the distortions of the yield loci. Differences in the yield locus behavior of the three materials were also observed: brass and the 2024-T7 alloy showed more severe distortions of the yield locus and a longer memory of their entire prestrain history than the 1100-0 aluminum. In addition, more “kinematic” translation of the subsequent yield loci was observed in brass and 2024-T7 than in 1100-0 aluminum. The 2024-T7 differed from the other materials, showing a yield locus which decreased in size subsequent to plastic straining. Finally, the implications of these observations for the constitutive modeling of multiaxial material behavior are discussed.

Plane Waves in an Elastic-Plastic Half-Space Due to Combined Surface Pressure and Shear

1966 ◽  
Vol 33 (1) ◽  
pp. 149-158 ◽  
Author(s):  
H. H. Bleich ◽  
Ivan Nelson
Keyword(s):  
Wave Propagation ◽  
Differential Equations ◽  
Half Space ◽  
Nonlinear Differential Equations ◽  
Plane Waves ◽  
Yield Condition ◽  
Shear Stresses ◽  
Von Mises ◽  
Plane Wave Propagation ◽  
Normal And Shear Stresses

The most general case of plane wave propagation, when normal and shear stresses occur simultaneously, is considered in a material obeying the von Mises yield condition. The resulting nonlinear differential equations have not been solved previously for any boundary-value problem, except for special situations where the differential equations degenerate into linear ones. In the present paper, the stresses in a half-space, due to a uniformly distributed step load of pressure and shear on the surface, are obtained in closed form.

Examination of the Stress Distribution in the Tip of a Pencil

2005 ◽  
Vol 73 (2) ◽  
pp. 335-337
Author(s):  
E. Pogozelski ◽  
D. Cole ◽  
M. Wesley
Keyword(s):  
Stress Distribution ◽  
Fracture Surface ◽  
Initial Position ◽  
Von Mises Stress ◽  
Shear Stresses ◽  
Worst Case ◽  
Position And Orientation ◽  
Von Mises ◽  
The Impact ◽  
Normal And Shear Stresses

The stresses within the tip of a pencil are examined theoretically, numerically, and experimentally to determine the position and orientation of the fracture surface. The von Mises stress is used to evaluate the impact of the normal and shear stresses due to compression, bending, torsion, and shear. The worst-case stress is shown to occur along the top edge of the inclined pencil point, where the normal stress is compressive. The resulting crack propagates diagonally downwards and towards the tip from this initial position, and is frequently observed to contain a cusp.

scholarly journals Investigation on Yield Behavior of 7075-T6 Aluminum Alloy at Elevated Temperatures

2020 ◽  
Author(s):  
Jianping Lin ◽  
Xingyu Bao ◽  
Yong Hou ◽  
Junying Min ◽  
Xinlei Qu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Plastic Strain ◽  
Elevated Temperatures ◽  
Equivalent Plastic Strain ◽  
Yield Behavior ◽  
State Dependency ◽  
Yield Criteria ◽  
Yield Loci ◽  
Von Mises

Abstract Aluminum alloys have drawn considerable attention in the area of automotive lightweight. High strength aluminum alloys are usually deformed at elevated temperatures due to their poor formability at room temperature. In this work, the yield behavior of 7075 aluminum alloy in T6 temper (AA7075-T6) within the temperature ranging from 25 ℃ to 230 ℃ was investigated. Uniaxial and biaxial tensile tests with the aid of induction heating system were performed to determine the stress vs. strain curves and the yield loci of AA7075-T6 at elevated temperatures, respectively. Von Mises, Hill48 and Yld2000-2d yield criteria were applied to predicting yield loci which were compared with experimentally measured yield loci of the AA7075-T6. Results show that yield stress corresponding to the same equivalent plastic strain decreases with increasing temperature within the investigated temperature range and the shape of yield loci evolves nearly negligibly. The experimental yield locus expands with an increase of equivalent plastic strain at the same temperature and the work hardening rate of AA7075-T6 exhibits obvious stress-state-dependency. The non-quadratic Yld2000-2d yield criterion describes the yield surfaces of AA7075-T6 more accurately than the quadratic von Mises and Hill48 yield criteria, and an exponent of 14 in the Yld2000-2d yield function gives the optimal predictions for the AA7075-T6 at all investigated temperatures.

Identification of the anisotropic behavior of an aluminum alloy subjected to simple and cyclic shear tests

2018 ◽  
Vol 233 (3) ◽  
pp. 911-927 ◽  
Author(s):  
Daghfas Olfa ◽  
Znaidi Amna ◽  
Gahbiche Amen ◽  
Nasri Rachid
Keyword(s):  
Aluminum Alloy ◽  
Kinematic Hardening ◽  
Plastic Anisotropy ◽  
Mechanical Tests ◽  
Material Behavior ◽  
Isotropic Hardening ◽  
Cyclic Tests ◽  
Shear Tests ◽  
2024 Aluminum Alloy ◽  
Cyclic Shear

The main purpose of this paper is to study the behavior of the 2000 aluminum alloy series used particularly in the design of Airbus fuselage. The characterization of the mechanical behavior of sheet metal on 2024 aluminum alloy and its response to various loading directions under monotonic and cyclic tests are extremely considered. To solve this problem, first, an experimental platform which essentially revolves around mechanical tests and then a series of optical and transmission electronic visualizations have been carried out. These mechanical tests are monotonic and cyclic shear tests applied under the same conditions on the test specimens of 2024 aluminum alloy. Cyclic shear tests have been carried out in order to show the Bauschinger effect and then the kinematic hardening phenomenon. The hardening curves of the simple shear test showed the Portevin-Le Chatelier effect for all loading directions. Next, the experimental results obtained (Portevin-Le Chatelier and Bauschinger effects) are discussed and analyzed in relation to the microstructure of the studied alloy using an optical microscope and a transmission electron microscope. Thereafter, the plastic anisotropy is modeled using an identification strategy that depends on a plastic criterion, an isotropic hardening law, a kinematic hardening (linear and nonlinear) law, and an evolution law. More precisely, particular attention is paid to the isotropic power Hollomon law, the saturation Voce law, and the saturation Bron law. In the case of the cyclic tests, linear kinematic hardening described by the Prager law and nonlinear kinematic hardening expressed by the Armstrong–Frederick law are introduced. Finally, by smoothing the experimental hardening curves for the various simple and cyclic shear tests, a selection is made in order to choose the most appropriate law for the identification of the material behavior.

scholarly journals Influence Of Lubricants On Wear Resistance Of Aluminum Alloy Strips Series 2XXX

2015 ◽  
Vol 60 (3) ◽  
pp. 1833-1838
Author(s):  
K. Żaba ◽  
P. Kita ◽  
M. Nowosielski ◽  
M. Kwiatkowski ◽  
M. Madej
Keyword(s):  
Wear Resistance ◽  
Aluminum Alloy ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
2024 Aluminum Alloy ◽  
Aluminum Alloy 2024 ◽  
Materials Used ◽  
Oil Company ◽  
Selection Of

Abstract The article presents a properly planned and designed tests of the abrasive wear resistance 2024 aluminum alloy strips under friction conditions involving various lubricants. Test were focused on the selection of the best lubricant for use in industrial environment, especially for sheet metal forming. Three lubricants of the Orlen Oil Company and one used in the sheet metal forming industry, were selected for tests. Tests without the use of lubricant were performed for a comparison. The tester T-05 was used for testing resistance to wear. As the counter samples were used tool steel - NC6 and steel for hot working - WCL, which are typical materials used for tools for pressing. The results are presented in the form of the force friction, abrasion depth, weight loss and coefficient of friction depending on the lubricant used and the type of counter samples. The results allowed for predicting set lubricant-material for tools which can be applied to sheet metal made of aluminum alloy 2024.

Optimization of Adhesively Bonded Single Lap Joints by Tapering of Adherends

2002 ◽  
Author(s):  
Prasad Nirantar ◽  
Erol Sancaktar
Keyword(s):  
Lap Joints ◽  
Material Behavior ◽  
Experimental Results ◽  
Shear Stresses ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Single Lap Joints ◽  
Single Lap Joint ◽  
Joint Deformation ◽  
Normal And Shear Stresses

The effect of tapering the ends of the adherend on the joint strength and joint deformation behavior of the single lap joint geometry was studied. First, the joints were geometrically modeled using finite element (FE) techniques involving linear, as well as nonlinear (bilinear) material behavior. Then, the FEA results were compared with the experimental results for different configurations of the single lap joints, and the FEA results were found to be consistent with the experimental results with the normal and shear stresses significantly decreasing in the modified geometries over those in unmodified geometries leading to increased loading capacity in modified joints, especially with small-angle taper (~10°).

Investigation on Porosity Content in 2024 Aluminum Alloy Welding by Yb:YAG Disk Laser

2011 ◽  
Vol 383-390 ◽  
pp. 6265-6269 ◽  
Author(s):  
V. Alfieri ◽  
F. Cardaropoli ◽  
F. Caiazzo ◽  
V. Sergi
Keyword(s):  
Aluminum Alloy ◽  
Laser Welding ◽  
Beam Quality ◽  
Welding Process ◽  
Porosity Formation ◽  
2024 Aluminum Alloy ◽  
Disk Laser ◽  
Aluminum Alloy 2024 ◽  
Slab Lasers

Aluminum alloy 2024 is extensively used in automotive and aerospace industries, but its application is limited due to the susceptibility to generate porosity during the welding process. Nevertheless, benefits from laser welding are clearly demonstrated. In addition, the use of a disk laser allows to obtain significant reduction in focus diameter and increased beam quality compared to traditional rod or slab lasers. The aim of the work is to discuss porosity formation as influenced by the thermal input provided, so bead-on-plate specimens in different conditions have been prepared. Porosity content is examined in relation to the fused zone extent and discussed considering interaction between laser and material. Higher thermal inputs are beneficial in full penetrative welds.

Evolution of Yield Loci for Aluminum Alloy AA6016 and Deep Drawing Steel DC06 under the Influence of Non-Linear Strain Paths

2013 ◽  
Vol 549 ◽  
pp. 21-28 ◽  
Author(s):  
Marion Merklein ◽  
Sebastian Suttner
Keyword(s):  
Aluminum Alloy ◽  
Deep Drawing ◽  
Strain Path ◽  
Material Behavior ◽  
Linear Strain ◽  
Hardening Behavior ◽  
Strain Paths ◽  
Yield Loci ◽  
Strain Path Changes ◽  
Stress States

The application of modern materials plays an important role directly under the aspect of lightweight potential. To exploit these options effectively a numerical accurate reproduction of the material behavior is indispensable. Especially in the case of large deformations a directional and strain rate dependent hardening behavior can be observed. By disregarding this effect significant failure in the computed stress state can arise, which can conduct to a corruption of the spring-back forecast. Within this contribution a new test method for analyzing the evolution of subsequent yield loci under strain path changes for the aluminum alloy AA6016 and the deep drawing steel DC06 is presented. In the first stage of the experimental investigations, yield loci with linear strain paths were considered to characterize the material behavior for the initial condition. On further experiments with several stress states the strain path dependent hardening behavior of the material is determined. The non-linear strain paths are realized through uniaxial prestrained primary specimens with following extraction of secondary samples for following stress states, e.g. a modified ASTM simple shear test specimen. Subsequent yield loci are investigated and compared to the yield surfaces Hill48 and Barlat 2000 (Yld2000-2d) with an isotropic hardening behavior. With this study the evolution of the yield locus for prestrained specimens is evaluated. The research of the subsequent yield loci for strain path changes serves as basis for further scientific investigations with a view to assess different approaches of isotropic-kinematic hardening models in consideration of the analyzed steel and aluminum sheet metals.

A note on the yielding of an accelerating, non-homogeneous disc of varying thickness and density with radial loading

1978 ◽  
Vol 13 (1) ◽  
pp. 59-63
Author(s):  
G V Gurushankar
Keyword(s):  
Uniform Density ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Uniform Thickness ◽  
Varying Thickness ◽  
Von Mises Criterion ◽  
Yield Loci ◽  
Von Mises ◽  
Radial Loading ◽  
Special Case

The influences of non-homogeneity and density on the normal stresses and shear stresses developed due to the acceleration of a disc, of varying thickness, at any particular instant, are analysed. Yield loci, on the basis of von Mises' criterion, are found for discs of varying thickness and uniform thickness with a bore ratio ( a/ b) of 0.25 and also for linearly varying ( p = 1.0, q = 1.0) and nonlinearly varying ( p = 0.5, q = 0.5) density and homogeneity. A homogeneous, uniform density and uniform thickness disc forms a special case of the analysis.

scholarly journals Investigation on Yield Behavior of 7075-T6 Aluminum Alloy at Elevated Temperatures

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Jianping Lin ◽  
Xingyu Bao ◽  
Yong Hou ◽  
Junying Min ◽  
Xinlei Qu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Plastic Strain ◽  
Elevated Temperatures ◽  
Equivalent Plastic Strain ◽  
Yield Behavior ◽  
State Dependency ◽  
Yield Criteria ◽  
Yield Loci ◽  
Von Mises

Abstract Aluminum alloys have drawn considerable attention in the area of automotive lightweight. High strength aluminum alloys are usually deformed at elevated temperatures due to their poor formability at room temperature. In this work, the yield behavior of 7075 aluminum alloy in T6 temper (AA7075-T6) within the temperature ranging from 25 °C to 230 °C was investigated. Uniaxial and biaxial tensile tests with the aid of induction heating system were performed to determine the stress vs. strain curves and the yield loci of AA7075-T6 at elevated temperatures, respectively. Von Mises, Hill48 and Yld2000-2d yield criteria were applied to predicting yield loci which were compared with experimentally measured yield loci of the AA7075-T6. Results show that yield stress corresponding to the same equivalent plastic strain decreases with increasing temperature within the investigated temperature range and the shape of yield loci evolves nearly negligibly. The experimental yield locus expands with an increase of equivalent plastic strain at the same temperature and the work hardening rate of AA7075-T6 exhibits obvious stress-state-dependency. The non-quadratic Yld2000-2d yield criterion describes the yield surfaces of AA7075-T6 more accurately than the quadratic von Mises and Hill48 yield criteria, and an exponent of 14 in the Yld2000-2d yield function gives the optimal predictions for the AA7075-T6 at all investigated temperatures.

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