A simplified error estimator for the CB method and its application to error control

•We propose a simplified error estimator for the Craig–Bampton method.•Computational cost is significantly reduced with negligible accuracy loss.•The contribution of a specific substructure to an eigenvalue error can be estimated.•The computational efficiency and an error control strategy are demonstrated. In this paper, we simplify the error estimation technique developed for the Craig–Bampton (CB) method (Kim et al., 2014). The original formulation is simplified by neglecting insignificant terms, a new error estimator is obtained, and thus computational cost is significantly reduced with negligible accuracy loss. In addition, the contribution of a specific substructure to a relative eigenvalue error can be estimated using the new formulation, in which the estimated relative eigenvalue error is represented by a simple summation of the substructural errors estimated. Therefore, the new formulation can be employed for error control by using the detailed errors estimated for a certain substructure. Through various numerical examples, we verify the accuracy and computational efficiency of the new formulation, and demonstrate an error control strategy.