Development of a condensation scheme for transverse rotational degrees of freedom elimination in identification of beam crack parameters

摘要

An identification algorithm has been developed with main objective to estimate transverse crack flexibility coefficients and as a by-product the equivalent crack depth, based on the force-response information. The algorithm requires eliminating some of the transverse degrees of freedom (dofs) of the system especially all the rotational dofs because of practical difficulty of measuring them. Conventional condensation schemes (e.g. static and dynamic) fail to eliminate these rotational dofs especially at crack element nodes. For eliminating the rotational dofs at crack element nodes a condensation scheme has been proposed in the present paper based on the physical consideration of the problem. The present condensation scheme has been illustrated through numerical examples for different transverse crack depths and at various crack locations. The scheme has been tested with incorporating random measurement noise in the response.