Omnidirectional Full-Field Displacement Reconstruction Method for Complex Three-Dimensional Structures

Abstract

On the basis of advanced functional structures such as aeronautics and astronautics, it is common to arrange strain measurements at finite points on the structure and then reconstruct the displacement field of the structure to predict the health situation of the structure. Unlike the previous methods of predicting one- and two-dimensional structures displacements using simplified conditions, this paper presents a set of technical schemes and operational procedures for measuring strains in any direction on complex three-dimensional structure to reconstruct three-dimensional displacement field. First, a general strain–displacement transformation equation is derived and proposed for a complex three-dimensional structure in any direction. Second, an extended order method and a point selection strategy are proposed in order to make better use of measurement information and improve accuracy. We construct an optimization model and determine the optimal number of measurement points and modal order by using high-performance simulated annealing (HP-SA) algorithm. Next, we build an experimental system and select a specific complex three-dimensional structure to verify our work. Finally, we validate and discuss the theory proposed in this Paper with experimental data, and verify the reconstruction accuracy. After eliminating the factors of the system error, the relative error can be controlled in an ideal range of 2–5%.