scholarly journals An Experimental Study of Initial and Subsequent Yield Surfaces in Plasticity

1958 ◽  
Vol 25 (2) ◽  
pp. 201-209
Author(s):  
P. M. Naghdi ◽  
F. Essenburg ◽  
W. Koff
Keyword(s):  
Experimental Study ◽  
Shear Stress ◽  
Aluminum Alloy ◽  
Shear Modulus ◽  
Axial Stress ◽  
Fourth Quadrant ◽  
Stress Plane ◽  
Yield Surfaces ◽  
Elastic Shear ◽  
Tubular Specimens

Abstract Experimental results for twenty-five tubular specimens of a 24S-T-4 aluminum alloy, subjected to combined torsion-tension-reversed torsion, are reported in a study of the initial and two subsequent yield surfaces covering the first and the fourth quadrant of the axial stress-shear stress plane. Results are also given for two additional specimens subjected to tension followed by torsion, in order to compare the values of the initial shear modulus at the initiation of twist with the elastic shear modulus.

Effect of Cyclic Loading on the Yield Surface

1979 ◽  
Vol 101 (1) ◽  
pp. 59-63 ◽  
Author(s):  
F. Ellyin ◽  
K. W. Neale
Keyword(s):  
Aluminum Alloy ◽  
Steady State ◽  
Cyclic Loading ◽  
Yield Surface ◽  
Stress Ratio ◽  
Axial Stress ◽  
Repeated Loading ◽  
Plastic Response ◽  
Initial Yield ◽  
Yield Surfaces

The effect of repeated loading on the yield surface is investigated experimentally for an aluminum alloy. Initial yield surfaces under combined axial stress and torsion are first obtained, and yield surfaces subsequent to steady-state plastic response are then determined for various cyclic loading programs. The results suggest that the initial yield surface expands and translates under cyclic loading and that the form of the steady-state yield surface is independent of the stress ratio.

scholarly journals Fatigue Strength Evaluation of Welded Structure on Aluminum Alloy Car Body Based on Multi-Axial Stress

2021 ◽  
Author(s):  
Yiming Shangguan ◽  
Wenjing Wang ◽  
Chao Yang ◽  
Anrui He
Keyword(s):  
Shear Stress ◽  
Aluminum Alloy ◽  
Fatigue Strength ◽  
Normal Stress ◽  
Welded Joint ◽  
Axial Stress ◽  
Stress Component ◽  
Local Coordinate System ◽  
Strength Evaluation ◽  
Welded Structure

Abstract With the continuous development of the subway, the demand for its safety and stability is getting higher and higher. It is of great significance to accurately evaluate the fatigue life of the carbody to ensure the subway's safe operation. In this paper, the finite element model of a subway head carbody was established, and the fatigue strength of the welded structure on the carbody was evaluated based on Multi-axial stress. The local coordinate system was defined according to the geometrical characteristics of the welds. Local stresses perpendicular and parallel to the weld seam were obtained to calculate the stress ratio, stress range, and allowable stress value corresponding to the stress component. According to the joint fatigue resistance, the components of the degree of utilization and comprehensive degree of utilization are calculated to evaluate the structural fatigue strength under the survival rate of 97.5% and load cycles of 10 7 . The evaluation of the fatigue strength of the pivotal weld joints shows that the fatigue strength of the aluminum alloy carbody meets the design requirements, the weld of the carbody has a strong ability to resist fatigue damage. The fatigue strength of the weld is mainly affected by the normal stress component, while the shear stress has little effect on the fatigue strength of the structure. In addition, compared with the filleted weld joint and the butt-welded joint, the normal stress parallels to and perpendicular to the weld direction and shear stress have the greatest effect on the lap-welded joint. Meanwhile, the comprehensive degree of utilization of the lap-welded joint is the largest at 0.49. The introduction of multi-axial stress for the fatigue strength evaluation is beneficial when considering the material utilization degree in multiple structural directions. This research results provide a reference for fatigue strength evaluation of subway carbody's welded structure.

Some Observations in High Pressure Rheology of Lubricants

1982 ◽  
Vol 104 (3) ◽  
pp. 357-364 ◽  
Author(s):  
S. Bair ◽  
W. O. Winer
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Shear Stress ◽  
Shear Modulus ◽  
Amorphous Material ◽  
Base Oil ◽  
Elastic Shear Modulus ◽  
Limiting Shear Stress ◽  
State History ◽  
Elastic Shear

Experimental data are presented on viscosity, elastic shear modulus, and limiting shear stress of 12 liquid lubricants. The effect of adding a polymer V.I. improver to a base oil is discussed. The limiting stress of the amorphous material is shown to be dependent on the state history.

scholarly journals Moduli and modes in the Mikado model

Soft Matter ◽  
2021 ◽  
Author(s):  
Brian Tighe ◽  
Karsten Baumgarten
Keyword(s):  
Shear Modulus ◽  
Mechanical Model ◽  
Low Frequency ◽  
Vibrational Modes ◽  
Prior Work ◽  
Fiber Networks ◽  
Elastic Shear Modulus ◽  
Flexible Fiber ◽  
Elastic Shear

We determine how low frequency vibrational modes control the elastic shear modulus of Mikado networks, a minimal mechanical model for semi-flexible fiber networks. From prior work it is known that...

Exact equations for fluid and solid substitution

Geophysics ◽  
2014 ◽  
Vol 79 (3) ◽  
pp. L21-L32 ◽  
Author(s):  
Nishank Saxena ◽  
Gary Mavko
Keyword(s):  
Shear Stress ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Fluid Substitution ◽  
Pore Shape ◽  
Effective Shear Modulus ◽  
Stiffness Measurement ◽  
Saturated Rock ◽  
Mean Stresses

We derived exact equations, elastic bulk and shear, for fluid and solid substitution in monomineralic isotropic rocks of arbitrary pore shape and suggested methods to obtain the required substitution parameters. We proved that the classical Gassmann’s bulk modulus equation for fluid-to-fluid substitution is exact for solid-to-solid substitution if compression-induced mean stresses (pressure) in initial and final pore solids are homogeneous and either the shear modulus of the substituted solid does not change or no shear stress is induced in pores. Moreover, when compression-induced mean stresses in initial and final pore solids are homogeneous, we evaluated exact generalizations of Gassmann’s bulk modulus equation, which depend on usually known parameters. For the effective shear modulus, we found general exactness conditions of Gassmann and other approximations. Using the new exact substitution equations, we interpreted that predicting solid-filled rock stiffness from a dry rock stiffness measurement requires more information (i.e., assumptions about the pore shape) compared to predicting the same from a fluid-saturated rock stiffness.

Experimental Study of Stationary Shoulder Friction Stir Welded 7N01-T4 Aluminum Alloy

2016 ◽  
Vol 25 (3) ◽  
pp. 1228-1236 ◽  
Author(s):  
S. D. Ji ◽  
X. C. Meng ◽  
Z. W. Li ◽  
L. Ma ◽  
S. S. Gao
Keyword(s):  
Experimental Study ◽  
Aluminum Alloy ◽  
Friction Stir ◽  
Stationary Shoulder
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