The Theory and Simulation on the Access to the Strain Mode

Abstract

Usually the theoretical approach to obtain the strain modal are based on the traditional parameter identification methods; however, due to Complexity and low-precision of the traditional identification methods, it is obviously not practical for the large tower structure; based on the own characteristics of tower structures and combined with the modal analysis theory, feasibility of the strain modal obtaining approach under the different incentives is explored. Keywords-strain mode; access; accuracy I. INTRODUCTION As a very sensitive parameter to the local damage, the strain modal reflecting the structural inherent characteristics has been widely applied in the field of health monitoring and damage detection (1). Apparently obtaining the strain modal is critical step in terms of engineering applications. The approach should be based on traditional identification methods, and the Chinese scholar Li De-bao has carried out very systematic study in this direction, Literature (2)(3)(4) made clear the basic idea of the strain mode that the strain field of the vibration system may be the superposition of the specific characteristics of strain field with certain percentage, which is corresponding with the structural displacement modal (2), and systematically analyzed the physical meaning of strain modal as well as the specific ways to obtain it,which has laid a theoretical basis for the follow-up study. Literature (5) put forward the single-point incentive and more-points incentive experimental strain modal analysis method in theory. Literature (6) derived the detection approach of the structural strain modal based on the stochastic subspace, established the stochastic subspace method of the experimental strain modal analysis, and verified its correction by simulation. Literature (7) proposed the characteristic system method of the structural strain modal identification which further deepened theoretical knowledge of the strain mode; Literature (8) put forward the strain modal approach to obtain based on the fiber-grating sensing technology, and applied the advanced sensing technology in the strain mode measurement which enhanced the application value of the strain modal. In this paper, taking account into the complexity of traditional modal identification all above, feasibility of the strain modal obtaining approach under the different incentives is explored.