Samenvatting

This report contains the preliminary study for the concept design of EPC-BME ARIANE 2010. The EPC-BME (BME) is primary load carrying structure, also called lower engine frame, of ARIANE launcher. The project EPC-BME ARIANE 2010 is part of ARIANE 2010 launcher program. The ARIANE 2010 project main goal is to reduce the recurring cost drastically in order to become competitive in the future aerospace business. In addition, the launcher's performance wil1 need to be increased to accomrnodate higher payload for future needs.

From preliminary study (Internal technica1 notes; Ref. 12) a referred concept which is the 'load carrying' skirt concept has been selected. This new cylindrical skirt concept has been chosen primary to reduce costs of the current complicated high cost structure. On the contrary, the concept is vulnerable to buckling. The design has now been made of a cone / box concept. It has been envisaged that all equipment is installed inside the cone and therefore requires a considerable integration effort. In this study, the new design concept to be studied is the so called: Cone-Skirt concept. The major primary load carrying structures are to be kept and maintained in this concept.

Within the design process, there are 2 considerable problems, i.e.:
- Buffeting problem
- Out-of-date finite element model

In this study a new detailed finite element model of the BME Box structure is made using MSC PATRAN and analyzed using MSC NASTRAN. The result is verified with respect to the old model (version A5-v6A) and hand calculation.

This study also elaborates the additional skirt design concept inorder to overcome the buffeting problem. After the design concepts being generated, trade-off matrices are used to single out thepreferred concept. The dimension of the skirt is optimized in order to minimize the mass of the skirt. This wil1 influence the total mass of the BME.

The last part of this study is the analysis of the impact of the skirt to the existing BME on stiffness parameters. This analysis is done using the finite element model.