In recent years, aerospace structures, such as a space antenna and aircrafts tend to be larger and more flexible, and these structures are prone to vibrate easily. Generally, the vibration problem of structures is dealt with a projection of structural vibration into a modal coordinate system. Therefore, it is important to measure modal displacement with high precision. Many researches have been performed on the modal sensors which pick up only the specified modal displacements. In constructing the modal sensors, sensors such as a PVDF film are attached on the whole surface of structures or a large number of sensors are attached on the structure.
In the first part, the present paper shows a design method to construct highly precise modal sensors using a small number of sensors. In order to measure the modal displacement precisely, the sensor location is optimized to avoid the observation spillover.
In the second part of the present paper, the modal sensors are applied to the impact force identification problem to identify force location and history acting on structures. The technique to identify the location and history of the impact force from dynamic response of a structure is proposed.
edited by Akihiko YAMAMOTO