Detection of spring support locations in elastic structures using a gradient-based finite element model updating technique

A methodology is presented for detection of the location of simple translational spring supports in elastic structures by non-destructive and non-intrusive means, based on measured natural frequencies of the structure. A gradient-based finite element (FE) model updating technique has been used for such detection. Measured modal data along with an initially correlated FE model are used. The present study is a new application of an existing FE model updating technique. The proposed method involves the detection of spring support locations by updating the position parameters of the support in the FE model through the optimization of an error criterion based on the difference between measured and computed natural frequencies of the structural system. The location of the support appears explicitly as an updating parameter in the formulation of the problem. Three different numerical schemes for computation of the gradient of the eigenvalue derivative with respect to the support location have been evaluated. The results and various limitations observed while developing the current method have been presented through numerical examples and a simple experimental example.