An in situ ensemble impact monitoring and identification technique for fiber composite structures under multiple disturbances

Abstract

An investigation is conducted to develop a real-time automatic structural health monitoring technique for the identification and prediction of the locations and force magnitudes induced by foreign objects impacting on composite structures. Accordingly, an in situ ensemble impact monitoring and identification technique is proposed and designed with the usage of distributed sensor networks. Then, the entire impact monitoring and identification mainly consists of four sequential procedures, which are the sensor signal preprocessing, the forward model generator, the impact positioning, and the inverse model operator. In order to achieve good engineering applicability, several uncertainty factors were considered for the composite structures, which are diverse structure configurations, various carbon fiber prepreg layups in the carbon fiber–reinforced polymer specimen panels, and impact conditions. In addition, random interfering noises resulting from structural vibrations were also taken into account as the essential disturbances. Under the different technical conditions and disturbances arising from practical structure vibration environments, the accuracy of the predictions of impact forces and locations using the ensemble impact monitoring and identification technique is validated through a series of impact tests. The errors between estimated and actually measured quantities all fall well within the satisfactory limited range. It is concluded that the ensemble impact monitoring and identification technique is qualified to reconstruct the input forces in sufficient precision due to unforeseen impact events under changeable conditions; it is also able to effectively estimate unknown impact locations in complex adverse environments.