SENSOR PLACEMENT AND STRUCTURAL DAMAGE IDENTIFICATION FROM MINIMAL SENSOR INFORMATION

A method of prioritizing sensor locations on a flexible structure for the purpose of determining damaged structural elements from measured m odal data is presented. This method is useful in applications where pr acticality dictates only a small subset of the total structural degree s of freedom can be instrumented. In such cases, it is desirable to pl ace sensors in locations yielding the most information about the damag ed structure. No a priori knowledge of the damage location is assumed. The prioritization is based on an eigenvector sensitivity analysis of a finite element model of the structure. In addition, the dual proble m Is presented and solved, which determines the observability of chang e in the measured eigenstructure from the instrumented degrees of free dom. This analysis is used to determine the extent to which damage can be localized. An analytical example is presented that illustrates the relationship between the number of measured modes, the number of inst rumented degrees of freedom, and the extent to which damage can be loc alized, Additionally, an analysis of an experimental cant levered eigh t-bay truss assembly consisting of 104 elements instrumented with eigh t single-axis accelerometers is presented. The extent to which structu ral damage can be localized from the measurement data is limited by th e number of measured modes.