What is the nature of creep?

Concrete creep is defined as: deformation of structure under sustained load. Basically as long term pressure or stress on concrete can make it change shape. This deformation usually occurs in the direction the force is being applied. Like a concrete column getting more compressed, or a beam bending.

What is creep plastic?

Creep is the tendency of a polymeric material to deform permanently under the influence of constant stress, as applied through tensile, compressive, shear, or flexural loading. It occurs as a function of time through extended exposure to levels of stress that are below the yield strength of the material.

What is creep material?

Creep refers to a material science concept that describes the likelihood of a material to deform under an applied force of mechanical stress. Creep may also be known as material creep or cold flow.

Do all plastics creep?

One of the key properties of plastics that results from viscoelasticity is creep. If a polymeric material is under constant stress, a continual change in strain will be observed. Simply stated, the stressed object will continue to deform over time.

Is creep harmful or beneficial?

The effects of creep may thus be harmful. On the whole, however, creep unlike shrinkage is beneficial in relieving stress concentrations and has contributed to the success of concrete as a structural material.

What is the nature of the curve of a viscous creep?

Explanation: The nature of the curve for a viscous creep is a straight line passing through the origin while it is a horizontal line for sudden creep. 10. Diffusion creep is a type of creep. The slope of a strain-time graph increases with the increase in temperature.

What is creep and its types?

Creep is a type of metal deformation that occurs at stresses below the yield strength of a metal, generally at elevated temperatures. One of the most important attributes of any metal is its yield strength because it defines the stress at which metal begins to plastically deform.

What are creep resistant materials?

Creep-resistant materials are used in machines and facilities operated at high temperatures e.g. power engineering equipment. They must be able to withstand the highest possible operating loads at elevated temperatures and also be sufficiently resistant to high-temperature corrosion.

What is the mechanism of creep?

Creep takes place as a result of dislocation motion in a crystalline specimen by movement known as ‘slip’ (glide). As a result of such dislocation motion through a crystal, one part of the dislocation moves one lattice point along a plane known as the ‘slip plane’, relative to the rest of the crystal.

Is thermoplastic material?

A thermoplastic is a type of plastic made up of polymer resins that becomes a soft material when it is heated and becomes hard when it is cooled. These materials are easily recycled and do not show any chemical property changes when they are heated or cooled multiple times.

What is creep in viscoelasticity?

One of the key properties of plastics that results from viscoelasticity is creep. If a polymeric material is under constant stress, a continual change in strain will be observed. Simply stated, the stressed object will continue to deform over time. This change in dimension is known as creep.

How does plastic strain increase over time?

There are two physical mechanisms by which the amount of plastic strain increases over time, 1) Stress relaxation and 2) Creep. Creep is an increase in plastic strain under constant force, while in the case of Stress relaxation, it is a steady decrease in force under constant applied deformation or strain.

What is the difference between primary creep and strain rate?

1) Primary Creep: The process starts at a rapid rate and slows with time. Typically it settles down within a few minutes or hours depending upon the nature of material. Strain rate decreases as strain increases. At this state the process has a relatively uniform rate and is known as steady state creep. Strain rate is minimum and constant.

What is the stress strain curve of thermoplastic materials?

Figure 1 shows typical stress-strain curves from a polymer thermoplastic material and thermoset rubber material. Both the materials have plastic strain properties where when the material is stretched beyond the elastic limit there is some permanent deformation and the material does not fully return to its original undeformed condition.