For the certification of a new glider outer wing Akaflieg Darmstadt has to perform load tests to verify the performed strain simulations of the finite element model.
As part of a span enlargement project of the Akaflieg Darmstadt D-43 glider, new outer wings based on a fibre-plastic composite structure must be manufactured. To receive the certification of the new outer wings by the German Federal Aviation Authority (LBA), load tests were carried out to verify the previously performed strain simulations of the finite element model.
Due to the span increase from 18 m to 20 m, the length of the new outer wings increased to 1.5 m. For the load tests of the fibre-plastic composite structure, the temperature is at least 54°C. The load will correspond to 172.5% of the maximum loads occurring during operation.
Top view of the outer wing with highlighted strain gauge positions.
HBK's M series strain gauges for high alternating loads (1-LM16-6/350GE) are used to determine the strain on the component surface. Installed at different positions on the outer wing, the strain gauges are aligned in the fibre direction of the unidirectional (UD) bands of the fibre-plastic composite beam:
The load on the outer wing is applied by a crane and distributed via the load harness to four points on the underside of the wing. The lever arms of the load harness are adjusted in such a way that the bending moment, shear force and torsion moment curves occurring in flight are realistically represented.
The crane force is introduced at the upper beam and measured with a HBK miniature load cell U9C (1-U9C/20KN). To set the temperature of 54 °C, the outer wing is located in a heat cabin made of Styrofoam with fan heater.
Strain gauges positioned on the wing shell.
Test setup with load harness.
The load cell from HBK determines the crane force.
The results of the load test (strains and deformations) are used to validate the existing finite element model simulation of the outer wing. During the simulation, two strain curves were calculated on the upper side of the wing for Limit Load (100% maximum load - blue graph) and Ultimate Load (172.5% maximum load - orange graph).
The strain curves of the finite element model simulation provide very realistic results. The determined deformations deviate by a maximum of 4 %, strains by a maximum of 5 %. Reasons for the deviations are uncertainties in:
Comparison of strains from finite element model simulation and physical testing.
Under the motto "Research, Build, Fly", new types of gliders have been created at the Akaflieg Darmstadt since 1920. The Akademische Fliegergruppe Darmstadt (short Akaflieg) is a university group of the TU Darmstadt. They pursue the goal of researching motorless flying using thermals, building gliders and trying out innovative concepts.
Strain gauges (often also referred to as strain gages) are the key asset for measuring fatigue and testing materials for better and safer products. Whether it is in structural durability testing, structural health monitoring, or the production of OEM transducers, HBK's optical and electrical strain gauges are the first choice.
M series strain gauges are foil strain gauges for stress analysis of materials with high fatigue strength such as fiber composites. They can also be used in product development, for example in the aerospace or sporting goods industries.
Tension and compression load cells from HBK are especially suitable for use in tank weighing, plant engineering and process weighing.
Compression load cells from HBM are especially suitable for use in tank weighing, plant engineering and process weighing.
The QuantumX data acquisition system (DAQ) is the perfect tool for all of your test and measurement needs. For reliable data acquisition of different physical quantities and sensor technologies, QuantumX is the preferred choice. It has the unique capability to acquire any signal and sensor information.
HBK’s Engineering Solutions embarked on the challenge of developing a common Failure Reporting, Analysis, and Corrective Action System (C-FRACAS+) for NAVAIR Command’s 33 programmes, each comprising diverse aircraft and systems with unique data requirements.
HBK's Advanced Material Characterisation & Testing facility in the UK, has helped accelerate NIO's fatigue simulation capabilities through a unique combination of bespoke testing solutions to provide high quality material fatigue data and the power of nCode software.
Once a year in the Lost Village revellers gather to immerse themselves in four days of live music and festivities. HBK, in agreement with the local authority and with the help of Noisy’s noise monitoring platform connected to B&K 2245 sound level meters, reduced the sound levels, resulting in very few noise complaints over the weekend.
With a wide range of sound measurement tasks, VM Acoustics needed a measuring instrument, that could serve all their needs reliably.
The challenge car makers face every day is designing cars to withstand all possible use cases during their entire product lifecycle. To support these investigations, Stellantis uses nCode DesignLife software within their development processes for fatigue analysis.
To minimize errors and reduce setup time, automotive seating manufacturer, Faurecia, uses the Transducer Smart Setup app for modal measurements.
To ensure high quality and increase production yield, Volkswagen contacted Brüel & Kjær to equip DISCOM Production Testing System to pinpoint the root causes.
Collaboration with Airbus Defence & Space will model sound for low-noise flight plans
Aerospace leader Lockheed Martin has expanded its vibration measurement capabilities for testing satellite systems, with a 450-channel PULSE™ vibro-acoustic data acquisition system.
Brüel & Kjær has been selected by Dassault Aviation to provide high-pressure surface microphones for the development of the nEUROn experimental Unmanned Combat Air Vehicle (UCAV).
Airbus Defence and Space and Brüel & Kjær have successfully completed noise measurements on the Eurofighter jet, to calculate its on-ground noise exposure under different thrust and flight configurations.
Brüel & Kjær recently delivered their HVME (Hull Vibration Monitoring Equipment) solution to BAE Systems Submarine Solutions.
Brüel & Kjær is to supply Pratt & Whitney with a Static Engine Certification Test (SECT) System.
Engineering consultancy company ATA Engineering, Inc (ATA) has strengthened its ties with instrument and solution provider, Brüel & Kjær, with the procurement of a PULSE Data Acquisition and Analysis system.
Airbus has acquired a 250-channel Brüel & Kjær PULSE™ data acquisition system for multi-purpose noise and vibration testing.
Dassault Aviation has performed noise certification tests on their new Falcon 8X business jet, using an acoustic data acquisition and analysis system from Brüel & Kjær.
Aircraft manufacturers have been approved to use PULSE for aircraft noise certification according to international standards.
The French aerospace research centre, ONERA, has acquired a 200-channel Brüel & Kjær PULSE™ acoustic data acquisition system for wind tunnel testing.
After Airbus modified the A330 to create the military version, they needed to update the aircraft’s noise certification so it could still use civilian airports.
Gorenje wanted to increase their R&D efficiency with a faster acoustic characterization system. And they turned to us
Case Study featuring Lockheed Martin and how Brüel & Kjær helped test different variants of the F-35 jet with the aim of protecting ground crews from noise exposure and increasing the durability of the jets.
Ground Vibration Tests Prove to be a Key Milestone for NASA’s X-57 Maxwell
Acciona Infrastructure needed to increase competences and offerings for building acoustics and sound insulation, Brüel & Kjær provided the solution.
To decrease the hours spent driving between fields during harvest time, New Holland reduced the pass-by noise of machines, gaining a higher road speed rating.
Air France Case Study highlighting how Air France - a major player in engine MRO - optimized their Zephyr test bench using B&K Tescia Repetitive Testing System.
Crown Equipment Corporation explored how improving the sound of their forklift trucks could create a better product and a more satisfying user experience
BATZ uses HBK equipment for testing according to its customers’ requirements
The Novares Group looks beyond the current crisis to a future with a V8900 HBT1220 shaker from HBK.
Controlling noise and vibration in the railway sector is key for the well-being of residents and passengers alike
The technical complexity and regulations relating to noise and vibration of machinery and ships demand the latest technology
New ChovACUSTIC systems leverage all the benefits of state-of-the-art sound level meters
Noise control: When it comes to environmental noise, Gießen Regional Council and HBK are listening very carefully
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.