Sage-Tips

How do you calculate elastic recovery?

Elastic Recovery After a load is released from a stress-strain test, some of the total deformation is recovered as elastic deformation. The recovered strain is calculated as the strain at unloading minus the strain after the load is totally released.

Why is elastic strain recoverable?

The elastic deformation is temporary and is fully recovered when the load is removed. The plastic deformation is permanent and is not recovered when the load is removed, even though a small portion of elasitic part in the deformation is recovered. The recovered portion is called the elastic recovery.

Why is elastic recovery important?

Elastic Recovery (ER) is used by many highway agencies for modified bitumen grading specifications. The current ASTM/AASHTO standards for ER testing utilize the ductility bath as the measurement apparatus. The results show a good correlation between the ER-DSR and ER measured in the ductility bath (ER-DB).

What is elastic recovery in textiles?

Elastic recovery: elastic recovery of a fabric is the ability to return in its original size and shape when the fabric comes under breaking load condition.

What is elastic recovery of bitumen?

The elastic recovery of a bitumen is expressed as a percentage of the distance between the ends of the half-threads, which has developed 30 min after the division relative to the elongation length of 200 mm.

What is the function of elastic recovery in bending?

Springback or elastic recovery refers to the shape discrepancy between the fully loaded and unloaded configurations. Springback causes changes in shape and dimensions that can create major problems in the assembly.

What is recovery strain?

When a piece of rock is removed from the in situ state of stress, it tends to relax and thereby deform. The relaxation consists of an instantaneous elastic component and a timedependent (anelastic) recovery. This relatively recent stress measurement method is called the ‘anelastic strain recovery’ (ASR) method.

What is recovery in plastic deformation?

Recovery is a process by which deformed grains can reduce their stored energy by the removal or rearrangement of defects in their crystal structure. These defects, primarily dislocations, are introduced by plastic deformation of the material and act to increase the yield strength of a material.

What is elastic recovery after plastic deformation?

Introduction; Upon release of the load during the course of a stress-strain test, some fraction of the total deformation is recovered as elastic strain.

What is elastic recovery test of bitumen?

The elastic recovery is measured by the percentage to which the asphalt cement residue will recover its original length after it has been elongated to a specific distance at a specified rate of speed and then cut in half.

What is the difference between stretch forming and bending?

Stretch Forming involves placing an extrusion along a rounded, fixed bending die which is secured with clamps on each end. The machine will then rotate the clamped ends together, bending the extrusion to angles up to 180°. The extrusion takes its shape when it is bent around the bending die to reach its desired angle.

How does elastic strain recovery work?

For materials that display elastic strain recovery, the load causes permanent deformation in less elastic parts of the material and only temporary deformation in the more elastic parts of the material.

How to reduce the elastic recovery of rubber?

Depending on the type of rubber, elastic recovery can be reduced by a suitable degree of mastication as measured by mooney viscosity values or plasticity retention index]

What is the difference between elastic stress and shape recovery stress?

When SMPs are heated and deformed, elastic stress is generated, and the elastic stress is stored when SMPs are cooled down below Ttrans. If deformed and fixed SMPs are reheated above Ttrans the stress stored in them is released as shape recovery stress.

Is the elastic strain curve a straight line?

The elastic strain region of the curve is a straight line. The plastic or ductile part of the curve is not straight. In the diagram you show, the elastic strain recovery is given. So I assume you’re having a hard time understanding the diagram. Elastic strain recovery is just the metal springing back, elastically, when the load is released.