Question

1. Where are stress concentration produced and what design and manufacturing procedures reduce stress concentrations?

2. How do ductile and brittle materials differ in their response to tensile loads when a stress concentration is present?

Answer 1

1. Stress concentration is the location where stress is concentrated. These stress concetration occur at geometric discontinuities such as cracks, sharp corners, holes, and change in cross sectional area. To reduce the stress concentration, create fillets at sharp edges. Another moethod adopted is to drill a large hole near the crack.

2. In ductile materials, when a material changes from elastic to plastic zone, longer chains of molecules disparse the load from one place to another which prevents stress concentration under static loading.

In brittle materials, even a small increase in stress concentartion leads to fracture. Thus, in case of brittle materials stress concentration is important criteria under any type of loading.