Vibration Analysis of Simply supported beam

“Cracks are found in all machine components at micro or macro level”. Fatigue crack propagation depends on many factors that have a random character e.g. load changes the component geometry or material properties. In such circumstances it appears purposeful to use probabilistic models of crack propagation.Crack may be classified in categories such as: (a) Micro-structurally short cracks where the crack size is close to the grain size (b) mechanically short crack with a plastic area at crack tip of the same size or larger than the size of the crack and (c) physically short crack that propagates faster than long crack with the same stress intensity factor.