On the Rheology of a Traction Fluid

1989 ◽  
Vol 111 (4) ◽  
pp. 614-619 ◽  
Author(s):  
K. T. Ramesh
Keyword(s):  
Shear Stress ◽  
Flow Stress ◽  
Applied Pressure ◽  
Critical Shear Stress ◽  
Strain Rates ◽  
Plate Impact ◽  
Lower Strain ◽  
Shear Plate ◽  
Traction Fluid ◽  
Impact Experiments

Results are presented of pressure-shear plate impact experiments performed on a traction fluid. The overall behavior of this material appears to be very similar to that of elastohydrodynamic (EHD) lubricants such as 5P4E: the material exhibits a saturation of the flow stress with strain rate, and a nearly linear dependence of the critical shear stress on the applied pressure. The plate impact results are compared with those of other workers using completely different experimental techniques and operating at lower strain rates and much lower pressures. The results obtained from the various techniques are in general agreement.

Dynamic Plasticity

1983 ◽  
Vol 50 (4b) ◽  
pp. 941-952 ◽  
Author(s):  
R. J. Clifton
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Single Crystals ◽  
High Stress ◽  
Plastic Strain Rate ◽  
Strain Rates ◽  
Plastic Response ◽  
Plate Impact ◽  
Stage Of Development ◽  
Impact Experiments

Recent advances in the understanding of the dynamic plastic response of crystalline solids are discussed. At the level of individual dislocations progress is being made on measurements of dislocation mobility at high stress levels and on elastodynamics solutions for transient dislocation motions. More progress is required on the understanding of changes in mobile dislocation density during dynamic plastic deformation. Widespread use of the Kolsky (or split-Hopkinson) bar has resulted in a reasonably clear picture of the dependence of flow stress on plastic strain rate for polycrystalline metals deformed at strain rates up to 103s−1. Influences of strain-rate history, temperature, and pressure require further investigation. At strain rates of approximately 103s−1’ to 105s−1 there is increasing evidence of a marked increase in flow stress with increasing strain rate. Pressure-shear plate impact experiments appear to be attractive for studying plastic response in this high strain-rate regime. Differences, if any, between stress-path effects at quasi-static strain rates and at strain rates of 103s−1 and higher remain poorly understood. Larger-than-predicted precursor decay observed in plate impact experiments on single crystals remains unresolved and of continuing fundamental interest; however, the importance of precursor decay measurements in determining dynamic plastic response appears to be diminishing because surface effects and limitations on the resolution of wave-front profiles represent serious constraints on the inferences that can be drawn from precursor decay measurements. Modeling of dynamic plastic response of polycrystals in terms of the response of slip systems is in an early stage of development. Kinematics of finite deformation by crystalline slip and consistent averaging techniques for modeling polycrystalline response are understood reasonably well. Increased emphasis on the understanding of the dynamic plastic response of single crystals and on the influence of microstructure appear desirable for sustained progress. Physically based models of wide applicability are required.

Pressure-Shear Plate Impact Experiments at High Pressures

2020 ◽  
Vol 6 (4) ◽  
pp. 489-501
Author(s):  
C. Kettenbeil ◽  
Z. Lovinger ◽  
S. Ravindran ◽  
M. Mello ◽  
G. Ravichandran
Keyword(s):  
High Pressures ◽  
Plate Impact ◽  
Shear Plate ◽  
Impact Experiments

Measurement of the behaviour of high-purity copper at very high rates of strain

1995 ◽  
Vol 73 (5-6) ◽  
pp. 295-303 ◽  
Author(s):  
Frank Kamler ◽  
P. Niessen ◽  
R. J. Pick
Keyword(s):  
Additional Data ◽  
Pure Copper ◽  
Plate Impact ◽  
Commercially Pure ◽  
Shear Plate ◽  
Split Hopkinson ◽  
Impact Experiments ◽  
Very High ◽  
Commercially Pure Copper ◽  
Good Agreement

Published measurements describing the high strain rate constitutive behaviour of oxygen-free high-conductivity (OFHC) and commercially pure copper are limited and show considerable scatter. To provide additional data, a direct impact compressive split Hopkinson bar was miniaturized to utilize specimens, 640 μm in diameter and 686 and 292 μm in length. This paper describes the design of this apparatus and results for OFHC copper. Good agreement is shown with results from pressure shear plate impact experiments.

A Viscoplastic Theory With Anisotropic Hardening and Its Application to Pressure-Shear Plate Impact Experiments

1985 ◽  
Vol 52 (3) ◽  
pp. 629-633 ◽  
Author(s):  
A. Gilat
Keyword(s):  
Strain Hardening ◽  
Anisotropic Hardening ◽  
Plate Impact ◽  
Hardening Model ◽  
Commercially Pure ◽  
Shear Plate ◽  
Alpha Titanium ◽  
Impact Experiments ◽  
Theory And Experiment ◽  
Good Agreement

An elastic/viscoplastic theory that includes anisotropic strain hardening is presented. The theory is a combination of the elastic/viscoplastic formulation of Perzyna [4] and the anisotropic hardening model for time-independent plasticity of Mroz [6]. The theory is used in the analysis of pressure-shear plate impact experiments on commercially pure alpha titanium. Good agreement between theory and experiment is observed.

Application of Bodner Viscoplastic Theory to Pressure-Shear Plate Impact Experiment

1990 ◽  
Vol 112 (1) ◽  
pp. 52-55 ◽  
Author(s):  
A. Gilat ◽  
J. Tsai
Keyword(s):  
Bauschinger Effect ◽  
Normal Component ◽  
Uniaxial Stress ◽  
Strain Rates ◽  
Stress Tests ◽  
Plate Impact ◽  
Calculated Profile ◽  
Shear Plate ◽  
Shear Component ◽  
Impact Experiment

An application of the unified elastic-viscoplastic constitutive theory of Bodner [5] is presented. The material parameters in the theory, which includes directional hardening, are determined from results of uniaxial stress tests at constant strain rates. The constitutive equations are then used in numerical modeling of pressure-shear plate impact experiment. The results show that the measured normal component of the wave agrees well with the calculated profile. A small discrepancy, which can be accounted for by the presence of a Bauschinger effect, exists between the theoretical and the experimental shear component of the wave profiles.

Finite Deformation Analysis of Pressure-Shear Plate Impact Experiments on an Elastohydrodynamic Lubricant

1992 ◽  
Vol 59 (4) ◽  
pp. 754-761 ◽  
Author(s):  
K. T. Ramesh ◽  
R. J. Clifton
Keyword(s):  
Finite Deformation ◽  
Elastic Response ◽  
Stress Wave Propagation ◽  
Lubricant Layer ◽  
Deformation Analysis ◽  
Viscoplastic Material ◽  
Plate Impact ◽  
Transit Times ◽  
Shear Plate ◽  
Impact Experiments

Pressure-shear plate impact experiments on an elastohydrodynamio lubricant (5P4E) are interpreted by means of a full finite deformation analysis of stress wave propagation in an elastic/viscoplastic material. The elastic response is modeled as that of a neo-Hookean solid, modified to include compressibility in such a way that the shock velocity increases linearly with increasing particle velocity; the viscoplastic response is modeled by means of a thermal activation model in which the activation energy is taken to be pressure dependent. The parameters in the elasticity relation are determined from the rising part of the transmitted stress profiles, which are related to transit times for multiple reverberations through the thickness of the lubricant layer. The parameters in the viscoplastic model are determined from the shear stress transmitted after nominally homogeneous states of stress are established through the thickness of the lubricant. Good agreement between measured and computed wave profiles is obtained over the entire range of pressures used in the experiments.

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