How a triaxial stress state can arise at the root of a notch?

How a triaxial stress state can arise at the root of a notch?

In brief, the triaxial stress state occurs because the plastic deformation of the material closer to the notch is constrained by the surrounding material (away from the notch) that are experiencing a lower stress level.

What is notch effect?

A notch is basically each change of the cross-section of a component. It may come from drill holes, grooves or cross-sectional variations. Notches result in uneven stress distribution, leading to stress peaks – known as the notch effect.

What is a triaxial stress state?

Triaxial stress refers to a condition where only normal stresses act on an element and all shear stresses (txy, txz, and tyz) are zero. An example of a triaxial stress state is hydrostatic pressure acting on a small element submerged in a liquid.

What are the factors that affect the energy of impact?

Temperature and Strain Rate Most of the impact energy is absorbed by means of plastic deformation during the yielding of the specimen. Therefore, factors that affect the yield behaviour and hence ductility of the material such as temperature and strain rate will affect the impact energy.

What are the factors that affect notch sensitivity?

The notch sensitivity of a material is a measure of how sensitive a material is to notches or geometric discontinuities. Notch sensitivity is influenced by many parameters such as notch geometry. Three types of notch geometries, V-shape, U-shape and -shape notches of various sizes are considered in this investigation.

What are the two most common types of bending impact tests?

There are two standard kinds of impact test: Charpy and IZOD.

Which is type of impact test?

There are two main forms of impact test, the Izod and the Charpy test. Both involve striking a standard specimen with a controlled weight pendulum travelling at a set speed. The amount of energy absorbed in fracturing the test piece is measured and this gives an indication of the notch toughness of the test material.

What kind of stress test is a notched bar?

Notched-bar tension tests are performed on notched specimens of either rectangular cross-section, with varying thicknesses, or circular cross-section, with varying radii. For either type of specimen, the stress state will vary with the notch depth and notch root radius.

What happens to ductility in a triaxial state?

Furthermore, stress triaxiality effects, such as the progressive reduction of material ductility with increasing stress triaxiality factor (i.e., TF = σm / σeq) are accurately predicted ( Bonora, 1998 ).

How does multiaxial state of stress affect damage evolution?

In real components, multiaxial state of stress loading condition, induced both by geometry changes and external loading, represents the rule rather than the exception. Consequently damage evolution and model performance should be directly validated in these loading configurations and not only limited to the uniaxial test case.

When did rice and Tracy study ductile damage?

Rice and Tracy (1969) analytically studied the evolution of spherical voids in an elastic-perfectly plastic matrix.