Impact of a Nonlinear Viscoplastic Rod on a Rigid Wall

1966 ◽  
Vol 33 (3) ◽  
pp. 505-513 ◽  
Author(s):  
T. C. E. Ting
Keyword(s):  
Strain Rate ◽  
Power Law ◽  
Rigid Wall ◽  
The Other ◽  
Stress And Strain ◽  
Rigid Plastic ◽  
Residual Strains ◽  
Stress And Strain Rate ◽  
The Impact ◽  
Special Case

Barenblatt and Ishlinskii [5] considered the impact of a viscoplastic rod on a rigid wall in which the relation between stress and strain rate is linear. In this paper, their analysis is generalized to a power-law relation between stress and strain rate so that their results may be reduced as a special case. Some strikingly different behaviors are observed between linear viscoplastic materials and nonlinear viscoplastic materials. Comparisons are also made between the viscoplastic solution obtained here with the rate-independent, rigid-plastic solution by Lee and Tapper [2]. It is shown that the curves which represent the residual strains versus the axial length along the rod are concave upward for all viscoplastic rods. For the rate-independent, rigid-plastic rods, on the other hand, they are concave downward.

scholarly journals On the strain-rate sensitivity of columnar ice

1997 ◽  
Vol 43 (145) ◽  
pp. 408-410 ◽  
Author(s):  
M. E. Manley ◽  
E. M. Schulson
Keyword(s):  
Strain Rate ◽  
Power Law ◽  
Rate Sensitivity ◽  
Dislocation Climb ◽  
Stress And Strain ◽  
Displacement Curve ◽  
Power Law Exponent ◽  
Basal Dislocation ◽  
Image Position ◽  
Stress And Strain Rate

AbstractA power law relation between stress and strain rate of the formwas used to describe the response to strain rate of S1 ice loaded across the columns at –10° C. The rate exponent,n, decreased with increasing strain from about 4.6 at an observed peak on the load displacement curve to approximately 2.6 at a shortening of 2%. Analysis of these results and of the results of other authors on different forms of ice deformed at the same temperature suggests that the power law exponent,nis proportional toFc/FgThe parameterFc/Fgis the far-field basal dislocation climb force divided by the glide force.

scholarly journals On the strain-rate sensitivity of columnar ice

1997 ◽  
Vol 43 (145) ◽  
pp. 408-410
Author(s):  
M. E. Manley ◽  
E. M. Schulson
Keyword(s):  
Strain Rate ◽  
Power Law ◽  
Rate Sensitivity ◽  
Dislocation Climb ◽  
Stress And Strain ◽  
Displacement Curve ◽  
Power Law Exponent ◽  
Basal Dislocation ◽  
Image Position ◽  
Stress And Strain Rate

AbstractA power law relation between stress and strain rate of the form was used to describe the response to strain rate of S1 ice loaded across the columns at –10° C. The rate exponent, n, decreased with increasing strain from about 4.6 at an observed peak on the load displacement curve to approximately 2.6 at a shortening of 2%. Analysis of these results and of the results of other authors on different forms of ice deformed at the same temperature suggests that the power law exponent, n is proportional to Fc/Fg The parameter Fc/Fg is the far-field basal dislocation climb force divided by the glide force.

106 Power Law Relations between Stress and Strain-Rate Observed with Glassy Polymer under Uniaxial Strain conditions

2001 ◽  
Vol 2001 (0) ◽  
pp. 11-12
Author(s):  
Yasuhisa SATO ◽  
Takeshi SUZUKI ◽  
Wataru KIKUCHI ◽  
Masazumi KOMORI ◽  
Takuya ABE
Keyword(s):  
Strain Rate ◽  
Power Law ◽  
Glassy Polymer ◽  
Uniaxial Strain ◽  
Stress And Strain ◽  
Stress And Strain Rate

Implication of Mismatch Between Stress and Strain-Rate in Turbulence Subjected to Rapid Straining and Destraining on Dynamic LES Models

2005 ◽  
Vol 127 (5) ◽  
pp. 840-850 ◽  
Author(s):  
Jun Chen ◽  
Joseph Katz ◽  
Charles Meneveau
Keyword(s):  
Strain Rate ◽  
Momentum Flux ◽  
Stress And Strain ◽  
Time Lags ◽  
Water Tank ◽  
Subgrid Scale ◽  
Smagorinsky Model ◽  
Mean Velocity ◽  
Stress And Strain Rate ◽  
The Impact

Planar straining and destraining of turbulence is an idealized form of turbulence-meanflow interaction that is representative of many complex engineering applications. This paper studies experimentally the response of turbulence subjected to a process involving planar straining, a brief relaxation and destraining. Subsequent analysis quantifies the impact of the applied distortions on model coefficients of various eddy viscosity subgrid-scale models. The data are obtained using planar particle image velocimetry (PIV) in a water tank, in which high Reynolds number turbulence with very low mean velocity is generated by an array of spinning grids. Planar straining and destraining mean flows are produced by pushing and pulling a rectangular piston towards and away from the bottom wall of the tank. The velocity distributions are processed to yield the time evolution of mean subgrid dissipation rate, the Smagorinsky and dynamic model coefficients, as well as the mean subgrid-scale momentum flux during the entire process. It is found that the Smagorinsky coefficient is strongly scale dependent during periods of straining and destraining. The standard dynamic approach overpredicts the dissipation based Smagorinsky coefficient, with the model coefficient at scale Δ in the standard dynamic Smagorinsky model being close to the dissipation based Smagorinsky coefficient at scale 2Δ. The scale-dependent Smagorinsky model, which is designed to compensate for such discrepancies, yields unsatisfactory results due to subtle phase lags between the responses of the subgrid-scale stress and strain-rate tensors to the applied strains. Time lags are also observed for the SGS momentum flux at the larger filter scales considered. The dynamic and scale-dependent dynamic nonlinear mixed models do not show a significant improvement. These potential problems of SGS models suggest that more research is needed to further improve and validate SGS models in highly unsteady flows.

scholarly journals Measurements and Characterization of Turbulence in the Tip Region of an Axial Compressor Rotor

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Yuanchao Li ◽  
Huang Chen ◽  
Joseph Katz
Keyword(s):  
Strain Rate ◽  
Shear Layer ◽  
Turbulent Flows ◽  
Reynolds Stress ◽  
Suction Side ◽  
Stress And Strain ◽  
Spatial And Temporal Variability ◽  
Mean Flow ◽  
The Mean ◽  
Stress And Strain Rate

Modeling of turbulent flows in axial turbomachines is challenging due to the high spatial and temporal variability in the distribution of the strain rate components, especially in the tip region of rotor blades. High-resolution stereo-particle image velocimetry (SPIV) measurements performed in a refractive index-matched facility in a series of closely spaced planes provide a comprehensive database for determining all the terms in the Reynolds stress and strain rate tensors. Results are also used for calculating the turbulent kinetic energy (TKE) production rate and transport terms by mean flow and turbulence. They elucidate some but not all of the observed phenomena, such as the high anisotropy, high turbulence levels in the vicinity of the tip leakage vortex (TLV) center, and in the shear layer connecting it to the blade suction side (SS) tip corner. The applicability of popular Reynolds stress models based on eddy viscosity is also evaluated by calculating it from the ratio between stress and strain rate components. Results vary substantially, depending on which components are involved, ranging from very large positive to negative values. In some areas, e.g., in the tip gap and around the TLV, the local stresses and strain rates do not appear to be correlated at all. In terms of effect on the mean flow, for most of the tip region, the mean advection terms are much higher than the Reynolds stress spatial gradients, i.e., the flow dynamics is dominated by pressure-driven transport. However, they are of similar magnitude in the shear layer, where modeling would be particularly challenging.

Some Implications of a Nonlinear Viscoelastic Constitutive Theory Regarding Interrelationships Between Creep and Strength Behavior of Ice at Failure

1989 ◽  
Vol 111 (2) ◽  
pp. 144-148 ◽  
Author(s):  
B. D. Harper
Keyword(s):  
Strain Rate ◽  
Constant Strain Rate ◽  
Nonlinear Viscoelastic ◽  
Uniaxial Creep ◽  
Strength Behavior ◽  
Minimum Strain Rate ◽  
Strength Constant ◽  
Viscoelastic Constitutive Model ◽  
Stress And Strain Rate ◽  
Special Case

This study explores several possibilities for a correspondence in the behavior of ice at failure during uniaxial creep (constant stress) and strength (constant strain rate) experiments. The usual notion of failure in ice is employed (i.e., the occurrence of a minimum strain rate during a creep test and a peak or maximum stress during a strength test), and the behavior at failure is discussed in terms of a recently proposed nonlinear viscoelastic constitutive model for ice. It is demonstrated that no correspondence between creep and strength data can be expected in general; however, several approximate interrelationships do occur for the experimentally motivated special case of a constant (independent of stress and strain rate) failure strain.

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