Baumgartl R.,IABG mbH
European Space Agency, (Special Publication) ESA SP | Year: 2012
For more than 25 years IABG is operating its 320kN vibration system in testing of space and non-space applications. The vibration system is a multi shaker system, using four electrodynamic shakers, driving a 3×3m 2 head expander and a 3×3m2 slip table. During the recent years a modernisation program of the shaker system has been implemented. The purpose of this program was to exchange system components, which have reached their expected duration of life, as well as to exchange components which did no longer fulfil the state-of-the-art requirements in testing and thus to adapt the vibration system to future challenges. Two major components of the shaker system, which have been covered during the modernisation program, are the shaker tables (the head expander and the slip table). Being the direct interface of a vibration test facility to a specimen, the shaker tables are crucial regarding the shaker system overall performance. And this fact applies even more for shaker systems with large tables, because there are no off-the-shelf solutions in this area. During the recent 5 years IABG specified, designed and procured a new head expander and a new slip table for the 320kN shaker system. This paper describes the overall process investigating on the following listed aspects: - general requirements for the tables - definition of boundary conditions and guidance principles - specific areas of interest - definition of the table material and the manufacturing method - design solutions - challenges during manufacturing - results - table properties.
Albersdorfer K.,IABG mbH
European Space Agency, (Special Publication) ESA SP | Year: 2012
The knowledge of the actual interface forces and moments between test article and shaker is of great value for the performance of a vibration test on any space hardware. For this reason, IABG developed a new Force Measurement Device (FMD) to be used for dynamic spacecraft testing on their large shaker systems. A state-of-the-art hardware and software provide extremely accurate on-line signals of the resulting forces and moments, which can be directly applied in the real-time vibration control process. The basic FMD configuration consists of two plates, which are connected by sixteen tri-axial load cells as the force link, the corresponding measurement amplifiers and an electronic unit, the so-called FPU (force processing unit). The FPU is responsible for A/D conversion, application of mathematical operations and finally D/A conversion of the resulting variables. Standard outputs are six analogue signals for the sum forces and overall moments. However, any other kind of signal processing (e.g. group-wise summation) is possible, because the system bears up to twenty analogue output channels. Of course, the individual force signals as well as offline processing of the time histories are available, too. The FMD has successfully been used during the dynamic qualification of the LISA Pathfinder Launch Composite Module (LCM) on IABG's 320kN Multi Shaker System in April 2011. During this test campaign, the following important properties could be demonstrated: High mechanical stiffness, good linearity and low cross-talk, high accuracy and signal quality, reliable analogue signals for automatic notching. These key properties - with or without additional features - make the FMD a desirable tool for primary notching during S/C testing with its inherent contribution to test safety. This paper describes the design and functionality of the FMD, and gives a short review on its first use during a spacecraft testing.
Moroncini A.,BMW AG |
Cremers L.,BMW AG |
Kroiss M.,IABG mbH
Proceedings of ISMA 2010 - International Conference on Noise and Vibration Engineering, including USD 2010 | Year: 2010
Car body development and optimization in early concept phases using beams and shells FE models is a well-established process at the BMW NVH department. The goal for these concept investigations consists of providing mainly qualitative answers for the full vehicle concept regarding prescribed functional targets, in particular for vibrations and acoustic comfort. Weight reduction and construction space potential is to be revealed and various concept variation investigations are to be performed. When using beams and shells FE models the vehicle model is not defined in an exact geometrical way, but based on functional topological aspects divided into beams and plate structures. Using full shell FE models only plate thicknesses are parameterized and therefore available for optimization, whereby the use of 1D beam elements allows a parametric description of the complete beam cross section, using beam width, height and the respective wall thicknesses as design variables. Different standard load cases for car body design and optimization have been defined based on detailed analysis of a series of customer relevant full vehicle functional performance targets with respect to vibration and acoustic comfort. The optimization model is completed by the definition of a target function, seeking an optimal car body structure within the feasible design space, satisfying all requirements and constraints of all specified load cases for minimal total car body weight. The paper provides an overview of the current process, illustrated by an application case, and an insight in future methods development in the EC VECOM Marie-Curie Training Network context.
Trafford M.,AmSafe |
Klein S.,IABG mbH |
SAE International Journal of Aerospace | Year: 2011
AmSafe®, Airbus and IABG were the first in decades to undertake an ultimate forward load Full-Scale Test (FST) of a 9g1 Barrier Net. Barrier Nets are safety critical products used during an emergency landing (FAR25.561/CS25.561) to protect passengers and crew. When Airbus Military required an A400M Barrier Net they identified requirements well beyond the "normal" and demanded that payloads from a rigid structure to a frangible be restrained. AmSafe uses non-liner Finite Element Analysis (FEA) technology to analyse their nets and proposed an innovative solution for a new Barrier Net to satisfy these very demanding requirements. Given these new requirements, it was decided to also carry out a Full-Scale Test (FST). This test required the expertise of IABG, a testing facility based in Germany. The rig requirements - the capability of asymmetric loading, with a rigid and frangible payload and the unusual behaviour of a textile test object - made predicting the resultant load performance on the test set-up and the rig design very challenging. IABG developed a unique test set-up to perform the FST up to a maximum design load of 4.2MN. The Barrier Net was able to achieve the demanding requirements and better due to the innovative use of "Tear Webbing" (AmSafe patent pending). The Tear Webbing technology was able to share the load evenly with the aircraft attachment points. Seven tests were performed with the test-rig performing perfectly each time. The associated monitoring system provided load data for all Barrier Net attachment fittings to the aircraft, as well as total load application and distension data for the Barrier Net. The testing confirmed that the Barrier Net could achieve all the attributes that the FEA predicted. It also confirmed that the limitations stipulated by Airbus for the airframe were met. This first-of-a-kind test - undoubtedly a step forward for safety - is a testament to all three partners that this technically challenging project was a success. © 2011 SAE International.
Boker D.,IABG mbH |
Bruggemann D.,University of Bayreuth
International Journal of Hydrogen Energy | Year: 2011
We investigate how ignition through laser-induced plasma can improve the application of lean combustion, in particular in environmental conditions relevant to hydrogen internal combustion engines (ICE). Major design goals when developing combustion engines are increasing thermal efficiency and decreasing combustion emissions. High compression ratios, lean combustion and precise ignition timings are contributing factors in ICE optimization. In our studies, several gains from laser spark ignition are investigated. The high energy content of laser-induced ignition kernels are shown to speed up the development of the early flame kernels. These extended ignition kernels transfer into self propagating flames even in lean mixtures. Leaner mixtures are ignited in our experiments using laser spark ignition in comparison to conventional electrical spark plugs. Precise ignition timing is realized. Multi-point ignitions are synchronized on the timescale of microseconds to enhance the progress of combustion. We modified the locus of ignition in a mixture flow to decrease the temporal extent of flame contact with the wall. Therefore, burning duration and heat loss can be reduced. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.