WHAT ARE BACK stresses?
Back stress is long-range stress caused by the pileup of geometrically necessary dislocations (GNDs). A simple equation and a procedure are developed to calculate back stress basing on its formation physics from the tensile unloading–reloading hysteresis loop.
What is strain rate effect?
Strain rate effect is the basic property of solid materials while strain rate effect of nonuniform materials is more obvious than that of uniform materials. Concrete strength is highly sensitive to the process of loading.
What is yield point phenomenon?
Yield point phenomenon is understood to occur when stress drops down drastically because the locked in dislocations are set free. The dislocations are locked in due to presence of carbon in case of low carbon steels or mild steels.
What is the effect of strain hardening?
Explanation: Strain hardening improves metals’ hardness. It also improves UTS and yield strength. Ductility on other hand deteriorates due to dislocation forest.
What causes the bauschinger effect?
The Bauschinger effect refers to a property of materials where the material’s stress/strain characteristics change as a result of the microscopic stress distribution of the material. For example, an increase in tensile yield strength occurs at the expense of compressive yield strength.
What is strain hardening in stress strain curve?
Once the material yields, it begins to strain harden which increases the strength of the material. In the stress-strain curves below, the strength of the material can be seen to increase between the yield point Y and the ultimate strength at point U. This increase in strength is the result of strain hardening.
What is strain explain?
Strain is the amount of deformation experienced by the body in the direction of force applied, divided by the initial dimensions of the body.
What are the effects of yield point phenomenon?
Abstract. Materials in which the yield point phenomenon occurs exhibit a characteristic drop in the stress–strain curve at the end of the elastic (or mainly elastic) region. In most cases the subsequent plastic deformation takes place locally in deformation bands, often termed Lüders bands.
What are upper and lower yield points?
A point at which Maximum load or stress required to initiate the plastic deformation of material such point is called as Upper yield point. And a point at which minimum load or stress required to maintain the plastic behavior of material such a point is called as Lower yield point.
Why is it called strain hardening?
This implies that the metal is becoming stronger as the strain increases. Hence, it is called “Strain Hardening”. The plastic portion of the true stress-strain curve (or flow stress curve) plotted on a log-log scale gives the n value as the slope and the K value as the value of true stress at true strain of one.
What is meant by strain hardening?
Strain hardening is one of the most commonly used means of adding strength to an alloy. It is simply the use of permanent deformation to increase the strength of the metal. Other names for strain hardening are cold work and work hardening.
What is Bauschinger effect in chemistry?
Bauschinger effect. noun. Bau·sching·er effect | ˈbȯ-(ˌ)shiŋ-ər-. : the phenomenon by which plastic deformation of a metal increases the yield strength in the direction of plastic flow and decreases the yield strength in the opposite direction.
What is the Bauer effect?
Bau·sching·er effect | \\ ˈbȯ-(ˌ)shiŋ-ər-\\. : the phenomenon by which plastic deformation of a metal increases the yield strength in the direction of plastic flow and decreases the yield strength in the opposite direction.
What is the Bauschinger effect in steel?
High strength steels exhibit a significant Bauschinger Effect. Thus the material near the inner bore does not behave elastically during unloading, but actually reverse yields in compression., which in turn greatly reduces the tangential stress near the surface on the outside of the vessel.
What is the Bauschinger effect in cyclic plasticity?
In cyclic loading, an isotropic hardening model provides a poor representation of the stress-strain response for many metals. For example, Fig. 2.2 (A) illustrates a phenomenon observed in cyclic plasticity known as the Bauschinger effect, in which the yield strength in compression is reduced after an initial yield in tension.