A Time Domain Approach for Identifying Dynamic Forces Applied on Structures

A time domain approach based on the structural response is presented for identifying dynamic excitation forces applied on three-dimensional steel trusses. Sub-structure finite element model with a short length of measurement from only four or five accelerometers is required, and an iterative least-squares algorithm is used to identify the dynamic forces applied on the structure. The location of the input force is assumed to be known in the identification. Validity of the method is demonstrated by means of numerical examples using noise-free and noise-contaminated structural response. Both harmonic and impulsive forces are studied. The results show that the proposed approach can identify unknown excitations within very limited iterations with high accuracy and show its robustness even when noise-polluted dynamic response measurements are utilized.