“…In particular, modal expansion techniques have been used in mechanical and aerospace systems for shape and/or strain reconstruction using sparse displacement and/or strain measurements [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ] or fusing acceleration and strain measurements [ 30 ]. The aforementioned studies cover a number of applications, including components of mechanical structures [ 1 , 2 ], components of civil structures such as railway bridges [ 20 ], wind turbine jacket substructures [ 11 ], truss structures [ 12 ], wind turbine towers [ 7 , 8 , 9 , 10 , 16 , 25 ], wind turbine blades [ 27 , 28 ], offshore structures [ 11 ], components of industrial structures [ 17 , 21 ], roller coaster [ 18 ], rotating [ 26 ] and underwater structures [ 13 ], as well as biologicaly inspired wing structures for robotic applications [ 29 ]. Recently, it is suggested to use virtual sensing in isolated linear components of linear and nonlinear models of structures [ 31 , 32 , 33 , 34 ] considering the forces at the interface between the analyzed linear component and the rest of the structure as unknown forces.…”