Experimental dynamic analysis of cracked free-free beams

The use of modal-analysis techniques as nondestructive methods for the detection of cracks in beams is a current field of interest for various researchers. However, an extensive search of the published literature shows that there is very little information on experimental results, thus making it almost impossible for theoretical researchers to use published experimental data to validate their models.The authors, who are currently working in the field of crack detection through modal analysis, performed an extensive experimental dynamic analysis of free-free beams with the objective of validating theoretical techniques, under development, for the prediction of the location and depth of cracks in straight beams. This paper describes the first part of the authors' work. The experimental techniques used are described and results obtained for various locations and depths of cracks in a straight free-free beam are presented.