Vibrations within the structure of a helicopter are unavoidable. If normal modes overlap and resonate in the worst case, this can result in total loss of the helicopter within a very short time. During take-off and landing, contact with the ground is crucial. Either the vibrations are limited or components of the helicopter are deformed by impacts. This results in minimal structural changes that cause imbalances in the overall system.
Such vibrations can be prevented or at least reduced by means of design rules. However, ground resonance can never be fully precluded. That is why extensive tests of the entire frequency response range are carried out during the helicopter’s development phase.
Ideal sensors for this application are the triaxial capacitive accelerometers ASC 5421MF, which are designed for the medium frequency range starting at 0 Hz as well as the triaxial piezoelectric accelerometers of type ASC P203, which are optimally suited for vibration analysis up to 9 kHz.