Motion Transmissibility for Load Identification Based on Optimum Sensor Placement

Abstract

Knowledge on loads acting on a structure is important for analysis and design. There are many applications in which it is difficult to measure directly the dynamic loads acting on a component. In such situations, it may be possible to estimate the imposed loads through a measurement of the system output response. Load identification through output response measurement is an inverse problem that is not only ill-conditioned but, in general, leads to multiple solutions. Therefore, additional information such as the number and locations of the imposed loads must be provided ahead of time in order to allow for a unique solution. This paper focuses on cases where such information is not readily available and uses the concept of motion transmissibility for the identification of loads applied to a structure. The identification of loads through measurement of structural response at a finite number of optimally selected sensor locations is investigated. Optimum sensor locations are identified using the D-optimal design algorithm to provide the most precise load estimates based on acceleration measurements using accelerometers. Simulation results for multi-degree-of-freedom (MDOF) discrete and continuous systems are presented to illustrate the proposed technique. It is seen that the proposed approach is effective in determining not only the number of applied loads as well as their locations but also the magnitude of applied loads.