What is plastic flow in the earth?

What is plastic flow in the earth?

Plastic flow is a rheological phenomenon in which flowing behavior of the material occurs after the applied stress reaches a critical value (yield). This slope and the weight of the ice induce a shear stress throughout the mass.

How does plastic flow work?

In addition to basal sliding, which slowly moves the glacier downslope as a unit, plastic flow causes glacial ice buried underneath more than about 50 meters to move like a slow‐moving, plastic stream. In general, the rate of plastic flow is greater than the rate of basal sliding.

What causes plastic flow?

Plastic deformation is the permanent distortion that occurs when a material is subjected to tensile, compressive, bending, or torsion stresses that exceed its yield strength and cause it to elongate, compress, buckle, bend, or twist.

What is plastic flow in glaciers?

Glaciers are basically ice mountains that move. Their movement is typically a combination of processes, but the most common process is internal plastic deformation, or internal flow, which involves the slippage of ice layers within the glacier.

What is the flow rule?

The flow rule describes the interconnection between the next plastic strain increment at a stress state for a deformed material point. The direction of the plastic strain increment is always normal to the potential surface at the present stress state. (Normality condition).

What causes thixotropy?

Thixotropy arises because particles or structured solutes require time to organize. Some fluids are anti-thixotropic: constant shear stress for a time causes an increase in viscosity or even solidification. Fluids which exhibit this property are sometimes called rheopectic.

Where does plastic flow occur?

(b) Plastic flow: Occurs in the middle part of the glacier where the ice crystals deform plastically under the combined influence of the overlying ice and the downslope gravitational pull (Fig. 3).

What is the difference between basal slip and plastic flow?

Plastic flow involves the entire ice mass slipping along the ground, whereas basal slip involves movement within the ice. Plastic flow occurs in the deeper parts of the ice mass, whereas basal slip occurs at the base of the glacier only.

What causes glaciers to move?

Glaciers move by a combination of (1) deformation of the ice itself and (2) motion at the glacier base. This means a glacier can flow up hills beneath the ice as long as the ice surface is still sloping downward. Because of this, glaciers are able to flow out of bowl-like cirques and overdeepenings in the landscape.

What are the flow rules in plasticity?

The flow rule describes the interconnection between the next plastic strain increment at a stress state for a deformed material point. This relation reminds us of the stress‐strain relation for a viscos fluid and uses the principle of a plastic potential surface g.

What is a hardening law?

The hardening law, also known as hardening rules, describes how the yield surface changes under the plastic deformation. The hardening rule governs the change in material strength as the plastic material deformation. If the stress is constantly held at B, no further plastic deformation will be occurred.

What do u mean by thixotropy?

Freebase. Thixotropy. Thixotropy is shear thinning property. Certain gels or fluids that are thick under static conditions will flow over time when shaken, agitated, or otherwise stressed. They then take a fixed time to return to a more viscous state.

What is the meaning of the word plastic flow?

The word “caprine” refers to … Also called plastic deformation. But the jokes flow at such a torrential pace that duds are soon forgotten; the best are even Spamalot-worthy. He was also a charismatic, telegenic speaker with a face improved by plastic surgery several years earlier.

How is plastic flow related to Newtonian fluid?

deformation of a material that remains rigid under stresses of less than a certain intensity but that behaves under severer stresses approximately as a Newtonian fluid.

When does the flow of a material occur?

Rheological phenomenon in which flowing behavior of the material occurs after the applied stress reaches a critical (yield) value, such as with putty. McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

What happens when plastic is deformation beyond the point of recovery?

The deformation of a plastic material beyond the point of recovery, accompanied by continuing deformation with no further increase in stress; results in a permanent change in shape. McGraw-Hill Dictionary of Architecture and Construction.