With the increase in electric-powered transportation, and to prove that an aircraft could be electrically powered, NASA developed the X-57 Maxwell, its first all-electric X-plane, with the goal of lowering energy consumption, reducing emissions and lowering the noise during flight. In addition to making sure that the design was energy efficient, they also had to ensure that the aircraft was safe to fly.
NASA, therefore, built an analytical model of the aircraft structure to simulate and analyze the stresses that the aircraft would experience during a real flight using ground vibration testing (GVT). By doing this, they can uncover weaknesses in their designs and fix them before making expensive prototypes.
During a ground vibration test – performed before the first test flight – engineers subject the aircraft to a number of different vibration profiles, representing the envelope of normal flight manoeuvres, while measuring the response at hundreds of points around the airframe. The data was gathered using HBK’s LAN-XI data acquisition system and analyzer platform. HBK’s BK Connect® software was then able to test and analyze data from 191 test runs with 14 different test configurations.
The GVT results gave NASA a much better understanding of the modal characteristics of the X-57 configuration, and showed that the pre-test airplane analytical model did not capture all the modes that were observed during the test. Updating the model to show these modes is going to be a challenge for the project team, but the main result of the test is that they will have the necessary modal data to do it.
HBK provided support both before and during the GVT as one of the keys for success on this project. NASA engineers consulted with HBK before the test and throughout the duration of testing when an HBK application engineer was on-site to provide support.
You can read more here: Ground vibration tests | NASA’s X-57 Maxwell | Brüel & Kjær (bksv.com)