DAMAGE DIAGNOSIS USING STATISTICAL PROCESS CONTROL

Structural health monitoring is described in the context of a statistical process control paradigm. This paper demonstrates the application of various statistical process control techniques such as the Shewhart, the exponentially weighted moving average, and the cumulative sum control charts to vibration-based damage diagnosis. The control limits are first constructed based on the measurements obtained from the initial intact structure. Then, new data are monitored against the control limits. A statistically significant number of outliers outside the control limits indicate a system transition from a healthy state to a damage state. Environmental and operation conditions, such as temperature change and the magnitude variation of the input forces, are also incorporated into the monitoring process. Blind tests of various damage cases are conducted without prior knowledge of the actual damage scenarios to evaluate the performance of the presented control chart techniques.