A novel damage detection technique using scanning laser vibrometry and a strain energy distribution method

Combining scanning laser vibrometry and a strain energy distribution method , a novel vibration based nondestructive testing (NDT) technique has been d eveloped for detecting damage in structural components. In contrast to cont act sensors, scanning laser vibrometry is capable of noncontact full field sensing with significant spatial resolution, thus providing detailed vibrat ion deflection shapes. A derivative of vibration deflection shapes, strain energy distribution is shown to be a move sensitive parameter than fundamen tal vibration parameters for detecting damage such as cracking in the membe rs. Since the strain energy distribution method requires significantly more spatial data points than typical vibration tests, a scanning laser vibrome ter capable of providing adequate spatial density is used. This nonintrusiv e technique can provide quick and accurate test results for detecting hidde n damage. We present 1D and 2D damage detection results on simple structura l elements such as beams and plates. With further development, veal time st rain energy distribution computation and damage detection can be achieved.