Dynamic Strain Sensors and Accelerometers for Structural Testing: Cases of Measurements on a Civil Structure and on the GVT of an F-16 Aircraft

Ground Vibration Testing (GVT) of aircraft is a measurement campaign performed in the development process of an aircraft, with the objective of obtaining experimental data of the aircraft to validate and update the structural dynamic models, which can in turn be used to predict important behavior, such as flutter. These measurements are usually carried out using standard accelerometers, which lead to the identification of the displacement mode shapes. However, the use of strain sensors in vibration and modal related applications has recently gained popularity, due to some advantages, such as sensor size and the fact that strain relates directly to stress. This quartz strain sensor has very unique features: is reusable, so very cost effective, and easy to mount with cyanoacrylate, just like an accelerometer. And just like an accelerometer can be used with a direct connection with measurement system thanks to ICP® ™ technology. Furthermore this type of sensor is available in different versions offering wide frequency range, high sensitivity, range and resolution. In this paper, the main results of a GVT campaign on an F-16 aircraft will be shown, where the full aircraft was instrumented with accelerometers and one of the wings was also fully instrumented with piezo strain sensors. The main results of the test campaign will be shown, where both strain sensor and accelerometer measurements are processed simultaneously, resulting in the strain and displacement mode shapes, respectively, and some characteristics and advantages of carrying out the tests this way will be presented.