Tolk A.,Old Dominion University |
Davis P.K.,RAND Corporation |
Huiskamp W.,TNO |
Klein G.L.,Mitre Corporation |
And 3 more authors.
Proceedings - Winter Simulation Conference | Year: 2010
The international developments of the recent years resulted in a radical change of tasks the armed forces are conducting. Supporting M&S methods and tools can no longer focus on attrition, movement, and warfighting operations, but need to address reconstruction, crisis prevention, police tasks, and related efforts that are conducted in collaboration with or in support of civil agencies and organizations. A "whole of society" approach is needed, focusing on human, social, cultural, and behavioral (HSCB) modeling. This paper summarizes the position papers of a group of international experts in this emerging domain looking a methodological support to define a body of knowledge, establish communities of interests, integrate operationally relevant data, and work towards a supporting framework, and was prepared in preparation of a panel discussion during the Winter Simulation Conference 2010. ©2010 IEEE.
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.
Decker M.,IABG MbH |
Eiber M.,IABG MbH |
Rodling S.,IABG MbH
Procedia Engineering | Year: 2015
Hydroelectric, thermal or wind power plants contain large power transmitting components which are often produced from forged or cast iron. These components set high requirements to efficient and reliable methods for design, validation and quality assurance. Due to their large dimensions and the high forces and moments acting during operation, full scale fatigue tests with the actual components are usually not possible with the number of specimen required for a reliable verification of safety against failure. Hence, usually a theoretical fatigue assessment based on the results of finite element calculations and material parameters is performed. The great uncertainties about material parameters are covered by safety factors that reduce the allowable stresses. Since this reduction is normally applied for the whole component, the material tends to be over specified for regions that are not highly stressed. In this paper, important aspects will be shown that have to be taken into account when dealing with large cast or forged power transmitting components. A method for obtaining a set of valuable and reliable local material parameters for a safe fatigue assessment is presented that facilitates a better material utilization and also takes into account the need for precise criteria for quality assurance in series production. A special focus is set on the importance of metallographic investigations along the process of specimen testing and quality control. © 2015 Published by Elsevier Ltd.
Wagner M.,IABG MbH |
Decker M.,IABG MbH
Procedia Engineering | Year: 2015
The thermo-mechanical deformation behavior of the Nickel-base alloy 602 CA is simulated by a viscoplastic material model by Chaboche. This model contains elastic properties, nonlinear isotropic and kinematic hardening and time-dependent material behavior. All material parameters for the complex superposition of simultaneously varying mechanical and thermal loadings are identified by isothermal complex low cycle fatigue (CLCF) tests at specific temperatures. These tests contain different strain amplitudes, strain rates and hold times. The parameters are obtained by computational optimization using a deterministic optimization technique (Levenberg-Marquardt algorithm). As a result, thermo-mechanical deformation behavior under various operating conditions can be predicted in terms of the generated stresses. The accuracy of the modeling is verified by corresponding experimental TMF testing. Furthermore, the lifetime of the Nickel-base alloy 602 CA is determined by using a mechanism-based model. The parameters of the model are identified by low cycle fatigue (LCF) tests. © 2015 Published by Elsevier Ltd.
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.
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.
Berger U.,IABG MbH |
Hayo T.,IABG MbH
7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society | Year: 2014
Structural Health Monitoring (SHM) is often understood as the monitoring of the structure's fatigue. The fatigue consumption of an aeronautic structure is performed either by load or respectively strain monitoring and the analysis of the strain spectra or by identifying the fatigue crack initiation in-service. The fatigue life estimation in such cases is only possible with respect to the macroscopic crack growth. This paper is split in two parts. On one hand, it will give an overview about the IABG activities regarding the development and aeronautic application of SHM systems. Therein, it is demonstrated that a combined usage of fibre optical sensors as well as Lamb wave analysis on the fatigue test of an aircraft structural component allows precise conclusion regarding fatigue life consumption. It further allows to benchmark both technologies. Therefore, a specific concept and development of an on-board SHM System for the in-service use on an aircraft is presented. On the other hand, the requirements in order to technically qualify a generic SHM-system are illustrated and how IABG can support the SHM developer in this process, especially when higher requirements of Technology Readiness Levels are to be validated by the developer. Copyright © Inria (2014).
Kliche D.,IABG mbH |
Mundt C.,University of Federal Defense Munich |
Hirschel E.H.,University of Stuttgart
Shock Waves | Year: 2011
The hypersonic Mach number independence principle of Oswatitsch is important for hypersonic vehicle design. It explains why, above a certain flight Mach number (M∞ ≈ 4-6, depending on the body shape), some aerodynamic properties become independent of the flight Mach number. For ground test facilities this means that it is sufficient for the Mach number in the test section to be high enough, that Mach number independence exists. However, the principle was derived for calorically perfect gas and inviscid flow only. In this paper a theoretical study for blunt bodies in the case of viscous flow is presented. We provide numerical results which give insight into how attached viscous flow behaves at high Mach numbers. The flow past an axisymmetric configuration is analysed by applying a coupled Euler/second-order boundary-layer method. Wall boundaries are treated by assuming an adiabatic or radiation-adiabatic wall for laminar flow. Calorically perfect or equilibrium air is accounted for. Lift, drag, and moment coefficients, and lift-to-drag ratios are given for several combinations of flight Mach number and altitude, i. e. Reynolds number. For blunt bodies considered here, which are pressure dominated, Mach number independence occurs for the adiabatic wall, but not for the radiation-adiabatic wall assumption. © 2011 Springer-Verlag.
Kugler H.,IABG mbH
Proceedings of the 2012 ESA Workshop on Aerospace EMC 2012 | Year: 2012
Within the AIT-process the verification of magnetic cleanliness requirements is an essential pre-requisite to ensure mission success, especially for satellites with dedicated magnetic mission requirements i.e. SOLAR ORBITER. Magnetic cleanliness verification usually comprises a combination of analytical and experimental methods. Based on magnetic measurements performed on equipment level, the magnetic behaviour on system level may be assessed by applying analytical and numerical methods and models and then verified during a magnetic system test as a highly recommended end to end check. The experience from many space projects such as CLUSTER, HUYGENS, ODIN, CHAMP and LISA PATHFINDER, SWARM has proven that the MFSA allows to obtain high-precision magnetic measurements. By the measurements of the projects during the last years, it became obvious that the size and weight of scientific satellites is increasing dramatically. In addition the shape of some satellites has changed from a compact cylinder or cube form to a quite elongated one. From this fact it can derived that several methods typically applied during testing have to be adapted to take the bigger size and different forms of the test objects into account. © 2012 ESA.