Study Of The Sheet Metal Crack Detection

Structural damage detection is a recent development field, and meets the engineering needs of the formation and multidisciplinary research field. Significant structural damage will cause major destruction of casualties and economic losses, which requires people to detect damage and proposed maintenance program. Clamped on both ends of the beam and the four sides fixed plate of the structural damage diagnosis is still relatively small. Beam and plate structures are often used in engineering structures, so the structure of both theory and method of damage detection is important.Through the basic theory of structural dynamics and finite element simulation analysis, we get a theoretical analysis and finite element simulation of the structure of fixed beam and clamped plate vibration characteristics, and also do the finite element simulation of the structure with the crack. The natural frequencies and mode shapes of cracked and uncracked are got. We research the two structures impacted by cracks, and build an experimental model.Carried out the experimental modal analysis on both ends of the fixed beam with or without crack that location and depth of change with the mode. Analysis of the crack parameters impact on both ends of the fixed beam modal parameters, obtained the natural frequencies and modes with two sensitive parameters changes as the cracks and the deeper. Discuss the relationship of the sensitive parameters and the cracks location, depth.For the first time Carried out the experimental modal analysis on the clamped plate with or without crack and the crack location and depth of change in the mode. Analysis of the crack parameters impact on the clamped plate modal parameter, and obtained the form of higher mode changes as the initiation and enhance of cracks. Discuss the relationship of the sensitive parameters and the cracks location, depth.