A Micromechanical Prediction of Initial Yield Surfaces of Unidirectional Composites

1979 ◽  
Vol 13 (4) ◽  
pp. 288-302 ◽  
Author(s):  
K. Wakashima ◽  
Yoshio Suzuki ◽  
S. Umekawa
Keyword(s):  
Unidirectional Composites ◽  
Initial Yield ◽  
Yield Surfaces

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.

Time Dependence in Biaxial Yield of Type 316 Stainless Steel at Room Temperature

1983 ◽  
Vol 105 (4) ◽  
pp. 250-256 ◽  
Author(s):  
J. R. Ellis ◽  
D. N. Robinson ◽  
C. E. Pugh
Keyword(s):  
Stainless Steel ◽  
Room Temperature ◽  
Transient Flow ◽  
Time Dependent ◽  
Time Data ◽  
Yield Behavior ◽  
316 Stainless Steel ◽  
Hardening Behavior ◽  
Initial Yield ◽  
Yield Surfaces

This paper describes two biaxial experiments which investigated time and rate effects in the yield and deformation behavior of type 316 stainless steel at room temperature. The first experiment was aimed at determining the effect of probing rate on small-offset yield behavior. The primary aim of the second experiment was to investigate time-dependent flow after loading beyond initial yield. An additional aim was to investigate the effect of radial (3 σ12 = σ11) and nonradial preloads on the yield and hardening behavior. The first experiment showed that for the limited range investigated, 100 to 500 με/min, the probing rate had little effect on yield behavior. The small differences observed in the size and position of certain yield surfaces were shown to be related to the sequence in which the yield loci were determined. The second experiment showed that yield surfaces suffered considerable distortion from their initial near-circular form after both radial and nonradial preloads beyond initial yield. It also showed that the hardening behavior was predominantly kinematic for both types of preload. The strain-time data obtained after the preloads in this experiment showed characteristics typical of creep curves. A transient flow period was observed with high initial strain rates diminishing one or two orders of magnitude during the 0.5-h hold periods. This means that in detailed mechanical modeling of this material, careful attention should be given to time-dependent effects, even at room temperature.

scholarly journals Overview of an Experimental Program for Development of Yield Surfaces Tracing Method

2021 ◽  
Vol 11 (16) ◽  
pp. 7606
Author(s):  
Jan Štefan ◽  
Slavomír Parma ◽  
René Marek ◽  
Jiří Plešek ◽  
Constantin Ciocanel ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Plastic Flow ◽  
Experimental Technique ◽  
Yield Surface ◽  
Equivalent Plastic Strain ◽  
Experimental Program ◽  
Metallic Materials ◽  
Initial Yield ◽  
Yield Surfaces ◽  
Loading Modes

This paper develops an experimental technique to evaluate the initial yield surfaces of metallic materials, as well as to study their evolution during plastic flow. The experimental tracing of yield surfaces is necessary for deriving and calibrating more robust phenomenological models of directional distortional hardening. Such models can be used to characterize the behavior of structures experiencing complicated and demanding loading modes, such as multiaxial ratcheting. The experimental technique developed in this work uses thin-walled tubular specimens, along with a servo-hydraulic machine, under various modes of tension/compression and torque. Identification of the onset of plastic flow is based on a small proof equivalent plastic strain evaluated from the outputs of a contact biaxial extensometer firmly attached to a specimen surface. This allows for evaluation of both the initial yield surface, as well as theevolved yield surface after a plastic prestrain. Throughout a test, continuous and fully automatized evaluation of elastic moduli and proof plastic strain is assured through algorithms written in C# language. The current technique is shown to provide promising results to effectively capture the yield surfaces of conventional metallic materials.

Neutron Irradiation and the Yield Surfaces of Copper

1967 ◽  
Vol 34 (1) ◽  
pp. 200-206 ◽  
Author(s):  
T. D. Dudderar ◽  
J. Duffy
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Yield Surface ◽  
Large Change ◽  
The Other ◽  
Polycrystalline Copper ◽  
Initial Yield ◽  
Principal Effect ◽  
Yield Surfaces ◽  
Extensive Plastic Deformation

Tests were conducted to determine the effects of irradiation and plastic deformation on the yield surfaces of polycrystalline copper. It was found that the principal effect of plastic deformation on unirradiated copper was to translate the yield surface without appreciably changing its size or shape. Irradiation, on the other hand, produced a very large change in the overall size of the initial yield surface; in other words, it produced an effect phenomenologically similar to extensive isotropic strain-hardening. In addition, the shape of the initial yield surface after irradiation was dependent on the plastic strain offset chosen to define yield. This effect was not observed for the unirradiated metal. Extensive plastic deformation after irradiation caused the yield surface to translate and grow smaller without significantly changing shape.

Interphase region effect on the biaxial yielding envelope of SiC fiber-reinforced Ti matrix composites

2018 ◽  
Vol 233 (6) ◽  
pp. 2044-2055 ◽  
Author(s):  
Mohammad Kazem Hassanzadeh-Aghdam ◽  
Seyyed Ahmad Edalatpanah ◽  
Sasan Azaripour
Keyword(s):  
Residual Stress ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Thermal Residual Stress ◽  
Matrix Composites ◽  
Interphase Region ◽  
Initial Yield ◽  
Sic Fiber ◽  
Wide Range ◽  
Yield Surfaces

The objective of this paper is to investigate the coupled effects of interphase and thermal residual stress on the biaxial initial yield surfaces of metal matrix composites using the simplified unit cell micromechanical model. The representative volume element of the composite consists of three phases, including unidirectional silicon carbide (SiC) fiber, titanium (Ti) matrix, and the interphase region between the fiber and matrix. It is found that the interphase slightly affects the initial yield surfaces of metal matrix composites without thermal residual stress. However, the results reveal that as the thermal residual stress is considered in the micromechanical modeling, the effect of interphase on the response of metal matrix composites becomes much more significant. The effects of the SiC volume fraction, interphase parameters including thickness and material properties on the yielding behavior of the metal matrix composites are examined. To demonstrate the validity of the model, comparisons are carried out between the results of the present model and other micromechanical methods as well as experiment. The extracted results could be useful to guide the modeling and design of a wide range of multiphase metal matrix composites.

Micromechanical Analysis of Composites by the Method of Cells

1989 ◽  
Vol 42 (7) ◽  
pp. 193-221 ◽  
Author(s):  
Jacob Aboudi
Keyword(s):  
Fatigue Failure ◽  
Material Properties ◽  
Fiber Reinforced ◽  
Micromechanical Analysis ◽  
Initial Yield ◽  
Yield Surfaces ◽  
Fiber Reinforced Material

A micromechanics theory based on the analysis of a repeating cell in a fiber-reinforced material is reviewed. The analysis leads to the prediction of the overall behavior of various types of composites from the known material properties of fiber and matrix. The capability of the theory in providing the response of elastic, thermoelastic, viscoelastic, and viscoplastic composites, as well as their initial yield surfaces, strength envelopes, and fatigue failure curves, is demonstrated.

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