Identification of Axial Forces on Statically Indeterminate Pin-Jointed Trusses by a Nondestructive Mechanical Test

This work concerns the stress-state identification, produced by loads or dislocations, of statically indeterminate structures. In particular, this paper deals with the case of pin-jointed trusses, since they are a combination of simplicity of the structural model with very interesting technical applications. We present an approach that follows the main guidelines of the flexibility method to relate an additional load and the consequent nodal displacements. When a sufficient number of nodal displacements are measured, they produce a system of equations that when solved furnishes a complete reconstruction of the stress-state to identify. In order to highlight the potentialities and the limits of the proposed approach and also to delineate its main characteristics, some simple tests are discussed and analyzed.