Dynamic Analysis with Varying Parameter using the Factorial Design Method
- Paper number
IAC-06-C2.3.08
- Author
Dr. Andreas Rittweger, EADS Astrium Space Transportation, Germany
- Coauthor
Dr. Stefan Dieker, Germany
- Coauthor
Dr. Jochen Albus, EADS Astrium GmbH, Germany
- Year
2006
- Abstract
Dynamic responses are depending sensitively on the knowledge of the model parameter (masses, stiffness, damping). These parameter can vary or change due to different reasons, eg.: • Various payload models have to be considered in the launcher/payload coupled analysis leading to different responses • A model parameter is non-stationary, it changes over the time (eg. propellant loading or a compensator stiffness due to different pressurization) • There are uncertainties in a model parameter and a range around the estimated parameter shall be considered • Due to the customer requirement a design parameter shall be kept variable in a certain range and the design verification shall consider this flexibility (e.g. a tank family with different cylindrical length) Presently the above mentioned problems are dealt by a huge amount of parametric investigations, usually using large FE models and resulting in a time consuming effort. An efficient way to deal with these problems is the Factorial Design Method. This method allows a systematically approach applying only a minimum of time consuming FE analyses with large models. The method is derived from the well known method of Design of Experiments, but the experiments are here substituted by FE-analyses. The basic idea is to establish a simulation model containing the interaction of different design parameter which is described by their factorials. The coefficients of the simulation model are determined by using orthogonal fields which is possible due to normalized design parameter (varying between -1 and +1). The Factorial Design Method has been applied on different examples to predict dynamic responses for varying parameter: • Payload variation for launcher/payload coupled analysis for Ariane 5. A payload class covering a range of effective mass, residual mass, axial and lateral frequencies, etc has been built and a simulation model has been established. Different worst case responses (e.g. interface load to payload or different equipment responses) were found systematically. • Variation of damping parameter (due to dependence on temperature and load level) at the Vehicle Equipment Bay of Ariane 5. The simulation model allows efficiently to determine the responses parametrically. The paper describes the method and the results achieved within Ariane 5 investigations. It highlights the benefit of this approach and discus also the limitations.
- Abstract document
- Manuscript document
IAC-06-C2.3.08.pdf (🔒 authorized access only).
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