Material Fatigue

Material fatigue is a phenomenon where structures fail when subjected to cyclic load. This type of structural damage occurs even when the experienced stress range is far below the static material strength.

               Fatigue may be produced by different kinds of stresses, such as thermal, bending, torsion, etc. where intermitted cycles of tension and compression are produced.

             Two most important characteristics of fatigue failure are ―

            (I) It is caused by dress level which would be safe if applied once , i.e. not subjected to repeated stress cycle.

           (II) Failure occurs without any warning which means there is no plastic deformation, even in ductile materials such as structural steel.