What affects strain rate?

What affects strain rate?

As the strain rate increases we measure a higher yield stress and tensile modulus. In this case the strain rate was held constant and the temperature was varied. As expected, as the temperature increases the strength and modulus of the material decline, mimicking the effects of changing strain rate.

Which properties are sensitive to strain rate?

The yield strength is found to be more sensitive to strain rate than the ultimate strength was.

Does strain rate increase with temperature?

In general, it is observed that the stress increases with increasing strain rate, but decreases with increasing temperature.

How strain rate affects stress strain curve?

The curves of the strain hardening rate as a function of the true strain are shown in Figure 3c. It is observed that the yield strength and the flow stress increase with increasing strain rate, while the uniform elongation decreases with increasing strain rate.

What is high strain rate?

A higher strain rate requires a higher acceleration and velocity of dislocations nucleated in the specimen to accommodate quick deformation.

What is the strain rate sensitivity?

Strain-rate sensitivity (SRS) of flow stress is an important parameter for deformation mechanism of materials. Definition of SRS is based on incremental changes in strain rate during tests performed at a fixed temperature and fixed microstructure, to determine corresponding changes in flow stress.

How does temperature affect strain rate?

It is found that elevated temperature tends to decrease the strength in tensile and cyclic tests, whereas increasing strain rate appears to improve the strength, and in strain-controlled isothermal fatigue tests, higher temperature results in shorter fatigue life for a given stress amplitude.

What is strain rate material?

Strain rate is the change in strain (deformation) of a material with respect to time. The strain rate at some point within the material measures the rate at which the distances of adjacent parcels of the material change with time in the neighborhood of that point.

What is meant by strain rate?

Strain rate is the rate of deformation caused by strain in a material within a corresponding time. This gauges the rate where distances of materials change within a respective period of time.

How are strain rates related to time and temperature?

Strain rate is the reciprocal of time. Longer times are related to lower strain rates while shorter times are related to higher strain rates. Therefore, lower strain rates mimic the behavior observed at higher temperatures while higher strain rates reflect the behavior at lower temperatures. Figure 1 shows an example of this principle.

What are the effects of high strain rates?

High strain rates—events that occur over a short period of time—tend to favor the elastic properties of materials. Elasticity is associated with load-bearing performance as embodied in properties such as strength and stiffness.

How does strain rate affect the yield strength of metal?

At higher rates of strain the flow stress of material increases leading to higher loads on the equipment. The effect of strain rate on yield strength for an alloy is illustrated in Fig. 1.11. The factors described above influence the forming processes to varying degrees depending upon the temperatures at which the processes are carried out.

How is the strain rate of plastic determined?

The plastic strain rate is often determined by the material constants D and q of the Cowper–Symonds equation (see Section 3.2.3 in Chapter 3 ).