Acoustic emissions generated by a structure under stressed condition provide an insight in to the dynamic behaviour of flaws in the structure for characterization of failure modes. Fiber failure mechanism in T-700 carbon epoxy composites is characterized by testing unidirectional specimens in longitudinal mode. Acoustic emission parameters like amplitude, energy, duration, and signal strength have been recorded and studied with respect to the applied load to assess the fiber failure characteristics.
For more informations : http://www.ijesi.org/papers/Vol%202(4)/Version-6/D241926.pdf
This paper deals with fracture investigations of low pressure (L P) steam turbine blade of a 110 MW thermal power plant in Punjab in India. These blades were made from chrome alloy steel X20Cr13 (Tempered martensitic stainless steel). The main focus of the paper is the fracture analysis, which took place at the airfoil region at 203 mm from the root of the blade. One of the fractured blades was retrieved to identify the cause of failure. The investigations included the visual examination, SEM fractography, chemical analysis, hardness measurement, and micro-structural characterization. While preparing the test specimen, silicon rich phases were detected on the blade along with oxide scale present inside the corrosion pits and fractured region. Transgranular cleavage fractures along with beach marks are observed. The cause of failure is possibly the corrosion-fatigue. These causes of failure are also underlined in this paper.
viaScienceDirect.com – Case Studies in Engineering Failure Analysis – Fractographic investigations of the failure of L-1 low pressure steam turbine blade.
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Via Sciencedirect.com : A failure analysis was performed on the shaft of a conveyor belt drive pulley. The shaft failed after seven days in service. Failure mechanism was high cycle fatigue. Failure occurred due to improper reconditioning of the shaft.