What are the 2 main deformation processes for polymers?
The two main processes, which occur during the plastic deformation of organic polymers, are plastic deformation under the action of shear stresses and plastic deformation induced by tensile stresses.
What is polymer deformation?
At a microscopic level, deformation in polymers involves stretching and rotating of molecular bonds. More commonly, one distinguishes the deformation mechanisms in polymers as brittle, ductile (with or without necking), and elastomeric.
What are the different types of plastic deformation?
Plastic Deformation
- Elastic Deformation – The deformation caused is reversible, and the deformation disappears after the removal of applied forces.
- Plastic Deformation – The deformation is irreversible and it stays even after the removal of the applied forces.
What are the modes of deformation?
Five modes of deformation were identified: inextensional bending, equi-area shear, elastic stretching, processive intussusception, and chemorheological growth.
What is plastic and elastic deformation?
When energy goes into changing the shape of some material and it stays changed, that is said to be plastic deformation. When the material goes back to its original form, that’s elastic deformation. If more force or pressure is applied, then they have plastic deformation.
What are two types of forming processes?
Some of example of forming processes are: Forging. Extrusion. Rolling.
What is ductile deformation?
Ductile deformation indicates shape change of a material through bending or flowing during which chemical bonds may become broken but subsequently reformed into new bonds.
What are the three basic modes of deformation?
When a rock is subjected to increasing stress it passes through 3 successive stages of deformation. Elastic Deformation — wherein the strain is reversible. Ductile Deformation — wherein the strain is irreversible. Fracture – irreversible strain wherein the material breaks.
What are the three types of deformation?
Strain is produced by stress and produces three types of deformation: elastic, ductile, and brittle.
What are the mechanisms of deformation in polymers?
At a microscopic level, deformation in polymers involves stretching and rotating of molecular bonds. More commonly, one distinguishes the deformation mechanisms in polymers as brittle, ductile (with or without necking), and elastomeric. Figure 3.18 shows schematically the curves that correspond to these mechanisms.
Is there rotation of sample during plastic deformation?
This alteration imposes an intense plastic strain on the sample, and the process can be carried out as many times as necessary to obtain the desired plastic deformation, which is one of the main requirements of SPD techniques. It is important to emphasize that there is no sample rotation during the process.
What are the different types of deformation processes?
Deformation processes can be conveniently classified into bulk-forming processes (e.g., rolling, extrusion, and forging) and sheet-forming processes (e.g., stretching, flanging, drawing, and contouring). In both cases, the surfaces of the deforming material and of the tools are usually in contact, and friction between them has a major influence.
How does energy transfer occur in plastic deformation?
Energy transfer occurs within the plastic deformation zones as heat and external forces are transferred to the workpiece material by forming equipment through the tooling and the interfaces between the tooling and workpiece. In forging, the entire workpiece may undergo plastic deformation nearly simultaneously.