Application of vibration measurement to detect damage in casting

Modal testing has become commonplace in many industries today as a research and development tool. In this capacity, it is used primarily during product prototype development and for vibration problem in general . Many types of structural or parts faults will cause changes in the measured dynamic response of a structure. These changes will, in turn , cause change in the structure’s modal parameter . The purpose of the present work is to propose an improved damage detection and location based on the measurement of modal parameter (natural frequency and mode shape ) before and after faults , which they have varying extents, for three different sizes of Aluminum casing plates. This local damage can be translated into or characterization as a reduction of the local stiffness which , simulated in the presented numerical models using software package. After measured natural frequency , if a change is detected a statistical method is used to make the best match between the measured changes in frequencies and the family of the theoretical predictions. This predicts the most likely defect location . Analytical results are also used to check numerical results , which showed a good agreement with it , standard Aluminum plates were also investigated in this work . It results were compared with casting results for two boundary conditions . Also , the defect location charts that plotted with the support of deriving stiffness sensitivity equation showed a good agreement between the predicted defect site and the actual defect location for most of the study cases .