Creep & Fatigue

Creep : sometimes called ‘cold flow’, occurs when a material under stress deforms gradually over time. It is more severe in materials that are subjected to heat for long periods.

Made worse by heat

Fatigue : the embrittlement and failure of a material due to stress applied and relaxed repeatedly over many cycles.

Stress and relax = strain

—> a gas turbine engine can become a serious safety concern when operated of not sufficiently maintained.

—> the engine works by a spinning turbine made of many blades spinning at high speeds which eject hot gases propelling the engine forward.

By considering creep and fatigue, explain how the turbines of the engine can become a safety hazard.

• for creep, the movement is made worse by heat and is a slow process overtime.
• for fatigue, it’s continuous stress and relax which causes strain on the material which caused it to be brittle