Instead of commonly used representation of the system dynamics by a linear transfer matrix a physical, non-linear model of test rig and specimen is created and inverted. This invers model computes the required drive-files directly using the required specimen loads as input.
De-icing the wing leading edge in the wind tunnel
Fraunhofer LBF developed, manufactured and tested an innovative ice protection system for airplanes, based on Carbon Nano Tubes (CNT). The tests were conducted in a climatic wind tunnel at temperatures as low as -18° C. In total, three leading edge segments of the wing were examined. Two were equipped with the non-metallic heating system in different configurations, one segment, which served for reference purposes, did not have a heating system. These tests crowned several years of development and improvement and were based on, among other factors, the simulation of thermal, electrical and aerodynamic conditions. The wind tunnel tests showed a promising performance, both in the de-icing mode (with an artificially iced wing) and in the anti-icing mode (which prevents icing during a simulated flight through clouds at low temperatures).
Ultrasonic sensors for parallel characterization of coatings in a device for simulated weathering
Like other materials, polymers undergo aging processes. For this reason, the prediction of the service life of plastics in outdoor applications is of particular significance. Anti-corrosion coatings, resin-based composites for wind power stations, and, not least, components for use in cars, railways or aircraft demand high long-term stability. Given that long testing cycles result in high cost and extended development cycles, industry has always been looking to reduce testing times. One way of accelerating the testing procedure is through simulated weathering in the laboratory. However, in many cases, reproducing the results of outdoor weathering in the laboratory has proven to be difficult. New customized weathering cycles and validated methods of early damage detection are expected to remedy this situation.
Fully integrated, multiaxial isolation platform
Apart from the negative effect they have on human health, vibrations and noise may also be the cause of mechanical damage, functional degradation or diminished performance of machines and equipment. One specific area of application, in which even extremely small vibrations may have a substantial effect is the operation of high-precision analysis or production equipment such as scanning electron microscopes.
The production of aluminium castings depends on material-efficient, low-cost design strategies. Being able to reliably ensure the mechanical properties of aluminium castings is a necessity in order to get a real edge over competitors. This is possible by monitoring the strength properties from product development through to volume production.
Adaptive vibration absorber with travelling-wave motor
Fraunhofer LBF has developed an adjustable stiffness element, which is based on a very simple design and permits a wide range of adjustment.
Production of fiber reinforced composite components
Leading-edge products offering increased durability and safety are central to our activities – safety meaning not only a trouble-free service life, but also the reliable early recognition of potential damage, which, amongst other benefits, also results in a reduction of maintenance cost. The team at Fraunhofer LBF is committed to the development of new technologies and concepts for enhancing product safety. In addition to the traditional Woehler and Gassner lines, which have for several decades constituted the key element when it comes to characterizing materials and component properties, the Institute is developing new concepts and strategies to respond to operative safety and reliability issues.
Typical sensor design variants and dimensions
To detect vibration of motors, machines, facilities or the structures connected to them, two different types of sensors are often used: piezoelectric sensors and microelectromechanical sensors (MEMS). Due to their high cost, piezoelectric sensors are mainly found in laboratory and test operation, whereas MEMS, thanks to their low manufacturing costs, are now installed in very many system boards.
Active mount
Amongst other factors, the interior acoustics of a vehicle is influenced by excitations originating from the road surface. The tire rolling noise is transmitted essentially through tires and chassis components to the vehicle body work. Reduction of the sound pressure level in the car interior can be expected, if chassis components are decoupled from the bodywork by means of active mountings.
In technical systems exposed to high levels of vibration, large movements have to be compensated and dampened. This is typically achieved with the help of elastomer components.
What if elastic components were intelligent and capable of actively deforming? What if they were able to lift masses and generate vibrations? If this were the case, these components would be able to control unwanted vibrations much more efficiently by introducing opposing vibrations, and even produce electrical energy from the vibrations they dampen.
Scientists at Fraunhofer LBF have developed a stack actuator, which makes use of the specific properties of electroactive elastomers, and unlocks a huge potential of entirely new applications.
Tested MultiTester (internal pressure)
From injection-molding simulation to component testing: Fraunhofer LBF's Department of Lightweight Structures has designed the "MultiTester", a new type of specimen for internal pressure testing. Using the MultiTester, the entire processing chain can be investigated. This includes the rheological balancing of the component, injection molding, material characterization and component testing. For designing durable lightweight structures with integrated functions, knowledge about system-influencing factors on durability and reliability is indispensable.
Battery housing in detail.
When it comes to developing electric cars that will be fit for the market, the integration of the energy storage systems is a big challenge for the car designers. First of all, the battery housing should make optimum use of the available installation space, in addition, lightweight design and function integration are important features, and on top of it all, the individual battery cells must be protected. The solutions should be geared to structural durability and negative effects on the driving dynamics must be avoided.
Pump demonstration with piezoelectric actuator
In recent years, AdBlue® has been used for exhaust gas aftertreatment in SCR catalysts in order to reduce nitrogen oxide emissions from diesel-powered engines. Currently, pumps which inject the AdBlue® at 5 - 10 bar are employed for this purpose.
Carbon fiber-reinforced polymer wheel (CFRP) - motor adapter flange and wheel hub motor section
If a vehicle has less weight, less propulsion power is required to achieve comparable driving performance. This means that less pollutants are emitted, which makes lightweight construction a key technology in the automotive sector. In addition, lightweight structures are the only answer to the high weight of the battery in hybrid and electric cars.
Fraunhofer Institute for Structural Durability and System Reliability LBF
