Due to their flexible and lightweight structure planes are particularly exposed to vibrations – even in steady state. Vibration testing at the ground and in flight is therefore indispensable for safe operation of any aircraft. Kistler provides a great variety of accelerometers (IEPE, MEMS, DC-response) to fulfill many different requirements.
Ground vibration testing (GVT), modal and structural analysis
Modal analysis is performed regularly on aircraft and their subcomponents to detect structural changes and potential damage. It includes experimental and analytical vibration investigations of acoustic, fatigue and functional aspects during the development phase of equipment and products.
One of the primary goals for design engineers is to determine the modal characteristics of the mechanical structure by testing and identifying the natural vibration modes. Ground vibration testing (GVT) typically calls for a large number of high-performance accelerometers at reasonable cost. Modal accelerometers from Kistler are available for three measurement ranges, including 5 g, 10 g and 50 g, offering an accurate frequency and phase response within the specified frequency range.
High channel count systems of this type must offer the required technical properties, but easy handling during installation is also of the utmost importance. Short installation times, low error rates and reliability over a 10-year timeframe are the key criteria. There are two key parameters to reduce error rates and time needed for installation: TEDS capability (Transducer Electronic Datasheet) and the sensitive axis alignment in relation to the overall coordinate system.
Easy handlingFor fast and easy installation: special clips or housings enable flexible orientation of the sensitive axis.
Flat frequency responseModal sensors from Kistler are characterized by a flat and repeatable frequency response, especially towards low frequencies. We also provide specific low-frequency calibration certificates and phase response characterizations on demand.
Low noiseThe low-noise performance of ceramic-based acceleration sensor families allows measurement of very small signals with no need for heavier seismic masses that could modify the behavior of the unit under test (UUT).
TEDS capabilityThe IEEE 1451.4 TEDS automatically transfers sensor parameters to TEDS-capable signal conditioning, to minimize transcription errors and record-keeping tasks.
Flight vibration testing (FVT) – we design the right accelerometers for each scenario
During flight testing, engineers validate the aircraft design by performing operational structural vibration testing. Many flight test scenarios are then applied to the aircraft in order to validate the shock and vibration performance of all aspects of the aircraft, including the control surfaces.
With regard to flight vibration testings (FVT), the flutter and buffeting tests are essential stages in the procedure for a new design qualification. In buffeting tests, flight load data is acquired so that real condition inputs can be defined for future structural testing requirements. These tests involve higher frequencies, so they need IEPE accelerometers to measure the vibration-induced load inputs into the structure and components.
As opposed to buffeting tests, flutter testing is typically performed with DC-response accelerometers; in this case, the aim is to study the aircraft's aeroelastic stability so that safe flight conditions are ensured.