Health structure monitoring for aircraft and rotorcraft through inverse finite element method (IFEM)

Abstract

Structural health monitoring (SHM) is an important task in system health management applications for aeronautic and space transportation vehicles, manned and unmanned. The rotorcraft are also extremely needed in various fields of interest, from military to civilian (search and rescue, environmental surveillance and monitoring, entertainment). This work presents an innovative structure design and control through an inverse finite element method-based, which compute the full-field displacements reconstruction of a three-dimensional shell/plate deformations from experimentally measured surface strains. The full-field displacements are useful for the preliminary design and inspections of the rotorcraft loads, caused by maneuvers or gusts. Goal of this paper was to validate the high accuracy predictions of deformations afforded due to the inverse finite element method (iFEM). Overall formulation was based on the minimization of a least-squares functional that uses and compares the strains extracted due to embedded sensors with the strains of linear, first order shear-deformation theory. The test article was a thin plate equipped with embedded sensors (strain gauge sensors) which permit to extract surface strains in real-time, used as input data for shape sensing. The plate was used to approximate a rotorcraft fuselage skin, in further work analyzed.