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Damage Identification in Structural Components Using Vibration and Wave Propagation Data. 1915

S. BANERJEE, F. RICCI, E. MONACO, A. MAL

Abstract


Two general approaches are being considered in an effort to develop an effective structural health monitoring system for composite structural components with relatively complex geometries. One is the global approach, which measures and analyzes frequency response functions (FRF) for damage-induced changes in the vibrational properties. The other is a local approach whereby changes in the characteristics of ultrasonic guided waves propagating across existing defects or created by emerging defects are measured and analyzed. Improved ultrasonic and vibration test setups, consisting of either distributed high-fidelity piezoelectric sensor arrays or laser vibrometer, data acquisition boards, signal conditioning and dedicated software have been implemented. A damage index is used to calculate the changes in fundamental physical parameters from the measured signals at a number of control points from two different states of the structure. In the global approach, either changes in FRF amplitude or curvature is used to define DI due to its sensitivity to the appearance of damage, whereas, in the local approach the changes in the energy content of the transient signals is used to calculate DI. Examples of low velocity impact damage are considered in composite structural components with relatively complex geometries. It is found that the damage indices are pronounced at the control points closer to the damage locations and that the DI increases with the severity of damage. A baseline free damage detection technique using wave propagation data is also developed as a potential alternative.

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