The purpose of this paper is to propose an improved modal method for element MSE sensitivity analysis which could improve the computational efficiency significantly. A Lagrange functional of element MSE with the constraints of eigenproblem and normalization condition firstly, and then the Lagrange functional is differential so that the Lagrange multipliers can be calculated by the modal method. After that, the derivative of element MSE can be calculated directly without the regardless of design parameters. The efficiency of the proposed improved modal method is demonstrated by the numerical example of a truss structure. The results show that the proposed modal method is efficient without losing accuracy. And the proposed method can be used in engineering application such as model updating of bolt in machine tools. The proposed method presents great advantage for engineering application in structural dynamics area such as model updating and structural damage detection, as sensitivity analysis is almost the most time consuming step in these applications.
 

Elemental modal strain energy; Modal method; Modal strain energy; Eigensensitivity; Structure sensitivity analysis.